mrchipster, here is an example of an improvement made to your room dimensions simply by lowering your ceiling and bringing inward one of the walls.  You don't have to actually move a wall. Just build another wall section inset of the original and utilize that airspace as a huge bass absorber which you will need all that you can get. That cavity is perfect for becoming the "hidden" bass absorber flush within the wall.   You can also consider this type of modification around each wall proportionally to obtain the same room dimensions.  This way there would be no bass absorption units visible within the room. Just something that may interest you.

So let's get back to some more interesting eye candy...enough graphs for now.

So back to the in-wall system. These are the crossover networks which I designed on XSIM using measured driver data and running the simulator. Changes were made in real time so that I could see the results as values were changed, or circuits modified.  You saw the final outcome on the frequency graph within a range of 30 Hz to 20 kHz. Can't get much flatter than that! These have impedance stabilization circuits built in as well.

Components that make the most difference are premium grade.

red pill,

Thanks for the info and your time to give some feedback on my room.
I had used amroc a while back to see how bad (or good) my room was. I had not played with different dimensions at the time since I had no way of modifying the room dimensions as it stands but thanks for digging deeper and providing insight with what may work.

At that time, I realized the room needed a lot of work (I pretty much knew it based on the sound I was getting but was good to confirm). I added quite a bit of treatment (absorption, diffusion, corner traps, etc.) and it helped, but I'll probably add a little more. The saving grace for now is the fact that I've gone with relatively low power/high efficiency equipment and so long as I don't overload the room, I get great full and satisfying music and sound. (and of course Decware is what makes that all possible in my opinion)

I do wish I could crank it more when the mood strikes but that will only be possible with a reasonable room. I'm following this with great interest since I hope one day in the future I can actually create a room from scratch and build it on knowledge and insight from folks like you who are willing to share their ideas and results in a meaningful way.

Looking forward to your continuing documentary.

As another evening rolls by, I will continue where I left off and touch upon some pertinent information that explains my thought process about this project, why I chose to do what I did, and why that is relevant.

So in the beginning before the original walls were torn down, I thought very carefully about the amount of work that was going into the transformation of this room ( which I did myself 100%), and the projected cost of the materials, let alone what my time is worth in labor value. I considered the major factors for which I hoped to achieve in the end, and what it would take to bring those factors into reality for my room. Hey, nobody said this would be easy..

Here were my set of design objectives. First, I needed to make this room as soundproof to the rest of the house as much as I possibly could. Second, I needed to move a wall inward to satisfy the need for better room response which would give this small room a better chance of being successful. Third, I needed total isolation from the outside world so that there was no interference entering the room from the windows. Fourth, the windows would need to be completely eliminated as a very big problem, that being the fact that glass has no place in a serious audio room for obvious reasons. I would have to create sealed heavy duty covers that could easily be removable when needed, but yet make the windows airtight against outside noise. This also keeps the sound level of my music from being heard outside of the windows to where it was nothing above a low level sound at most.

Fifth, I needed to create a double leaf wall for soundproofing the barrier between this room and the adjoining room. I also had to create a way to install double doors with airtight seals in which to keep high SPL levels from being heard through the door. This in itself was a major feat to pull off.  I had to build a thick, heavy, solid door worthy enough of making this happen. No holes could be allowed in the door for locks or door knobs. That would immediately create a path for airborne noise to penetrate, therefore resulting in failure. A new type of lock would have to be designed to prevent this. and still be able to keep the door shut tightly against the frame seals.

Sixth, I wanted to build a stable full scale baffle wall that would be free of resonance, or any source of vibration resulting from the required isolation of the housing for the flush mounted speaker arrays.  I had to consider placement of these speakers within the wall to avoid null areas within the exact line of placement. A null area would create a condition where the output of low frequencies would be severely hampered, causing bass response to suffer. I was taking a huge gamble here, as there was no  real way of being sure the end result because it would have to be tested installed to actually know the results. By placing external speakers into the room along various positions of the wall would tell me nothing, because that would be like comparing apples to oranges. There would not be enough conclusive evidence to formulate a confident decision.

I knew that I wanted close proximity of the speakers as the array aligned directly with my left and right ears. (this has to be done in order to reduce the degree of inter-aural cross-talk. The main reason for flush wall(baffle) mounting of the drivers is to eliminate S.B.I.R.

So those were the main factors for which I had to implement within the design of this room.  And of course, I knew that a huge degree of bass absorption was an absolute requirement in order to give this room a chance.  That being done without creating a dead room from over absorption. I needed to retain a live sounding room, so this balance of interplay was going to be a challenge. Hey, that shouldn't be too difficult should it?  

Just like the way they rebuilt Steve Austin AKA "The Six Million Dollar Man", they could rebuild him, better, stronger, faster!   I guess I will just proceed and see what happens. 

So now this brings up another point which I need to convey about this room.  One of the great benefits I have with this room location within the house is that #1: It is an upstairs corner room with two of the walls being brick on the outside. #2: Above the ceiling is the attic. The joists in the attic above the room are filled with heavy layers of insulation. Both fiberglass and blown in cellulose types. So this does indeed help to provide some degree of sound reduction and bass absorption. Those heavy duty joists also become strong anchor points for which to hang my massive ceiling diffuser/absorption devices. #3: This room sits directly over the garage...no problems there. #4: I conveniently have dual closets, isolated by a center dividing wall which will be utilized as sealed air spaces behind the speaker baffle wall. This acts to provide the appropriate airspace needed for the rear waves of the driver arrays to flow without restriction. And most importantly, remain isolated from the main listening area forward of the baffle wall.  The fact that these twin closets existed was what gave me the idea of building a baffle wall. I saw this as a perfect opportunity.

Now one thing did occur to me that would have made a major sacrifice to the house layout. I knew that the unused bedroom on the backside of the closet space was beckoning me to expand this entire space into one large listening room. That would have been a major step in resolving my acoustic problems.  But I knew this would not be a wise thing to do, and besides, NO way in hell was my wife going to allow me to do such a thing!  I am lucky she went along with this dedicated audio room. She understands where I am coming from, and remains very understanding of that, but to eliminate a bedroom from a four bedroom house was not acceptable. It goes without question. The concept of it sounded so great, but then faltered quickly as logic set in.  

Closure of the dual leaf wall advances.








Detailed view (turned sideways) of sealed light switch housing shown mounted to the frame.







Looking down at the sealed isolation box housing the light switch.

The 1/2 inch OSB being installed with each seam being centered on a stud every time.  Each and every joint must be centered over a stud to insure a positive tight seal along with a solid connection. Acoustic sealant must be applied to the edges during installation. This paneling must be airtight.

You may note that all contact surfaces have felt attached to create an isolation barrier between the layers. This helps to minimize the transference of low frequency resonance.













Just about done closing up this wall with OSB. The next layer is Coroplast, which is a polypropylene corrugated material designed with rows of air pockets which is encased airtight.

This Coroplast provides an additional layer within the wall structure composition. The idea is to become a buffer between the layer of OSB, and the drywall so that the two hard surfaces do not contact each other. In my view, this layer acts like a spring, providing resistance to the flow of sound or resonance as it passes through.

Again, another attempt to further reduce the transmission of resonance through the wall. This will also add to the effectiveness of this wall to act like a very large bass absorber. This does create a full scale degree of airtight pockets which logically make sense to use for this purpose.

Here we start with the bare bone facts. This is what I envisioned in my mind as I sat and thought about my room execution for better acoustics. You are viewing the twin closets with a center dividing section to keep them isolated. That closet is associated with the bedroom on the other side of these closet spaces. The space next to the entry door has the access hatch for the attic. That is another project I had to deal with. That attic hatch needed rebuilt into an airtight heavy duty upgrade.

I totally rebuilt that framework to provide the symmetrical configuration required to serve my purpose. Of course this is nowhere near what it looked like when I removed the old drywall.



Now you can see how tempting it was for me to just remove this entire section and open the space up all the way to integrate both rooms.  Of course that was never really an option. This would have really been a great listening room if I had acquired all of that volume at my disposal.

Hey, I at least tried to convince my wife that if I could just push back the wall to where I could use the closet space, expanding my current audio room a few more feet in length, then build a double leaf wall for soundproofing, that I would be very pleased, and there would still be the other bedroom.  I already knew what that answer was going to be, and I definitely was not surprised! Life is always about compromise, and this was no exception.

 

Hey Donnie, Glad you asked.

I will try an attempt to convince you as to why this is so important. I think it will make sense to you.  If you disagree, then not a problem. But at least you asked.

I shall reiterate in another form of explanation in order to make sense of this to all in question.  Again, this is a very in-depth experiment for which I knew from the beginning would either be hit or miss in the outcome.

However, in a nut shell, the main reason for sealing everything air-tight is to reduce sound from leaking past the structure.  The sealant helps to avoid failure points for which any chance of sound reduction becomes null and void.  Now listen, I know very well that sound reduction is a very difficult thing to achieve, and there is a limit as to what one can do to enforce it.  That is acoustics 101.

It is a matter of design, and the materials used that will determine the level of sound reduction one achieves in a room.

The absolute best way, is to build a "room within a room", with full and absolute isolation from the surrounding structure. The second best method is to use dual leaf walls. But when you don't have that, it is vital to do everything possible to reduce the problem within a common structure. Using acoustic sealant is absolutely vital to this objective.

If I were to task you with building a metal container to hold water, using separate pieces of metal, with only the method of seam riveting used, how well do you think it will hold up without a leak as a result of omitting sealant? Not only along the structure seams, but the rivets themselves?  So does that not make sense when it comes to house structures which by the way, are not exactly built with tight tolerances?  At least not the older homes.  But I am referring to structure tolerances, not how airtight a house is against air leaks in general.

It is almost impossible to stop bass frequencies, but they can be greatly reduced with extreme measures.  The point of using sealant is secondary, but just as critical in order to prevent this transfer of noise/energy. If there is any crack or opening, no matter how tiny, sound will travel through that area, and so much for sound reduction.

You may ask yourself, why place vibration resistant feet under sensitive electronic equipment? Why place resonant free platforms under tube amplifiers to reduce the chance of negative influence upon the transformers and tubes?  If you understand those reasons, then understanding the use of acoustic sealant at every turn should be clear and relevant to the end result.

One of my primary concerns in building this room this way is to attempt a strong reduction in resonance from traveling through the walls, through the cracks, through any opening what-so-ever, all of which would make all of this pointless in the end. So yes,  these sealed spaces actually do pressurize by the back waves from the speaker array....40 inches of bass drivers per side. This is a bit like if they were mounted inside a speaker cabinet. The rear waves are prevented from exiting forward of the baffle wall. It is extremely important that this baffle wall remains stable and resonate free as much as possible. I don't need the structure to become excited by the lower frequencies and therefore begin resonating. Once that happens, this system has failed. The sealant between all joints acts like a resilient buffer in which to help block that transfer of energy.

I am subjecting a great deal of pressure behind this baffle wall from the the bass drivers at higher SPL input.  Just think about a new dodge demon with a supercharged hemi, pushing upwards of 1200 HP , and just running straight pipes.  Hit that throttle for a second and see what that does to the windows in the house.  Put the regular exhaust back on and everything is okay.  Perhaps a bit extreme as an example, but relative to get the point across.

 The main point of this no matter what, is to insure the best chance of soundproofing through isolation of the room boundaries. When I close the door and turn up the system, I don't want the house complaining about how loud my music is.  Look, this room was finished several years ago, I am just revealing the story of how it developed and why I did it that way.  I do intend to explain everything as much as possible. There is a reason for everything I do here, again, much of it is experimental. Whether right or wrong, I can at least say that I actually tried it and know the outcome from experience.

Now I am not ready to divulge the results of this experiment yet, but this whole story is leading to that conclusion. I am not going to disclose that result yet.  Let's just say that this system was put to the test for over 6 months. So I would imagine for something to remain as a daily system without rearing a multitude of problems, it would make sense to me anyway that something must have worked out alright with this baffle wall.

 However, it is nothing for me to reinstate the baffle wall back to it's original solid form. When the experiment is over, and if I decide not to retain the speaker array in the baffles, then not a problem. I prepared for the quick conversion back to a solid wall when I designed this system, knowing full well that there was a strong chance I will eventually do so. No two rooms are the same, No two rooms can have the same results. What works in one situation may very well fail in another. That is common knowledge.  

I am just going to leave you with this fact. I know from experience and everyday use of this room, that this works very well.  Regardless of the influence for which the sealant played upon all of this, the point is, my end result is spectacular! Far better than I anticipated. It is not perfect, nor is it by any means 100 percent soundproof. Then again, how many rooms really are?  Probably not very many.

My objective was to achieve a respectable degree of sound reduction to the point where I was not disturbing the house with resonating bass frequencies traveling throughout which would limit my use of higher output from the amplifier. This is one of the greatest problems with audio...disturbance from low frequencies. Seems to be a root cause for many types of problems in audio.  However, I can now play the system at some very intense levels without upsetting members of the family, or entertaining the neighbors. I can do this without walls shaking or having some crazy rattle constantly taxi my nerves.

As a before and after comparison, this room before was absolutely awful. There was always a major problem with external noise coming in, and any level of noise made within the room traveling out. I had to play my music at low levels or it became a problem in the house.  Besides, the acoustic situation was unbearable in this room to say the least.  It really was pointless to expect hearing good quality music within these boundaries.

 Now, that situation is the farthest thing from the truth. I simply could not be happier with a room this size. When I build things, I don't take shortcuts, and I don't use inferior materials! Do it right the first time or don't do it at all.  That is the difference between a novice, and a seasoned professional.  Build it right and it will last. Build it right and it will perform upon your expectations.

 I am forced to deal with a small room, but that does not mean It has to react like a small room.  It has worked out for me very, very well.  Anyway, my objective here is not to convince anybody of anything. Do it the way you want to. I am just relaying my own results.

 Thanks for the input.

Some images of the construction phase for the front baffle wall buildup.





This is a section that will become a mid-range diaphragmatic absorber module. This gets filled with rock-wool with an airspace between it and a flexible steel plate which goes onto the front flush with the wall and held in place with acoustic sealant. Frames made of MDF will get installed within these chambers.





This view is looking up at the center divider between the two closets. This will act as an isolation barrier between the two channels. Note that there is isolation between the two closet sections. The center divider is built like a dual leaf wall.





This view is inside of the closet space which sits behind the baffle wall. The attic access is seen above.

I am advancing ahead in the build since I think most people are getting bored, and this should really be seen to be understood. But hey, It is a challenge to keep the masses interested in acoustics, even though great interest should be strong for anyone wanting to know why their small audio room sounds so bad. Hey, after all, what have I gained from all of this?

 Reminder: THIS BUILD WAS FINISHED FOUR YEARS AGO. Since then, I have moved on with changes which have synchronized almost perfectly into what I have today.

Look, I want so badly to just jump ahead, and reveal everything I have experienced to date. (and as exciting as my current room acoustics are, not to mention what this does for my music), this will have to wait. Have patience, there is plenty of time here. After all, this story is all about my experience, and what these changes have done for me. I think many of you can relate to that.

I know many people today live in a "microwave processed world". But guess what, if you are really interested in something that will completely change your perspective on what a professional grade standard of excellence is like within a properly built audio room, this is something you really must experience to understand where I am coming from.

The end result is DRAMATIC, and SO realistic, that it would only take less than five minutes of your time to experience this room, and know exactly what I am talking about. You know, that is really the only way this can ever be truly conveyed. How can I possibly be expected to express what I have achieved today, when it only takes a few minutes of listening, to completely understand how huge this really is. This absolutely can NOT be conveyed over the internet. All of the audio graphs in the world are certainly never going to make the truth clear to you. This simply can only be perceived in an actual listening session.

 When I listen to well made studio recordings with my current configuration, I am stunned into just how deep the rabbit hole goes once the "Holy Grail" of music perception is experienced. Not just heard, that would be way too simple. But to be connected at a high level of bliss with every sense of perception possible to the maximum degree. I am now connected to the music, in a very physical manner to where my emotions are radically to the point where I feel as if I am "inside" of the music, free from boundaries. It is now automatic to completely forget that I am listening to speakers in a room. I have finally after all of these years(decades actually) been granted the experience I have always yearned after. If it were anything less, then this whole thing is pointless for me. Anything else falls short of what I am expecting.

In case you can't tell, I am very excited about what I experience now. I have never come close to hearing, feeling, or connecting to the music as I do now. It is a deep emotional connection that I have with the music as a result of all this. Something that I never experienced on this level of satisfaction before. This is as close to being in a live audience, listening to a huge symphony orchestra on stage, within an abundant spatial environment as I could ever get without actually being there. The pinpoint accuracy and crystal clear detail which seems to just float around your head is something that takes you to a completely advanced perception of what your recordings actually have to reveal. That did not happen overnight. It took a great deal of disciplined engineering on my part to make this happen. I can only say that I wish all that enjoy audio could experience this. It really takes things up several levels. That is why I stated, "My Audio Journey Evolution is in the final stage". I really have no reason to look any farther other than a degree of curiosity which we all have been influenced by.. That is how satisfied I am with my current room and system. But this does not mean I won't try other things or perhaps add a few more acoustic devices just to see if there actually can be something else extracted from the music.

*Spoiler alert: I am planning on enhancing the front wall, and the forward sections of the side walls with custom six feet tall poly-cylindrical diffusers based upon the advanced Ternary concept. I may even introduce some changes to that design in order to make it a "Quaternary" level of diffusion. I have an exact vision of that model standing directly between the speakers in alignment for which to immediately dissolve those nasty diffractions that ruin natural perception as would be well focused in a real world event. You know, that "ear-brain" perception to what is real, and what is "not real"? I have been wanting to experiment with this concept for a long time. I am now ready to see where this may take me. I plan to build this design concept at the end of this year. Expect to hear more about this around January 2025.

In addition, I have the plans laid out for a reduced scale (80%) version of the "lil headwrecker" design. I am only using that model as a starting base. I read about so much joy expressed from Steve about these speaker designs, (pretty much conveys the way I feel about my current audio room), that the curiosity factor took control of my thoughts and I knew I had to build a take on these.

This reduced version is built to accommodate a 8-inch full range driver. The major change is that I am going to alter this design with a 5 degree slope within the entire cabinet where everything is as if someone "warped" the entire speaker to where it leans backward proportionally.  Nothing changes internally to screw up the folded horn. I know from experience that a speaker raked backward anywhere from 3 to 7 degrees is usually something that takes the perception of the speaker to a higher level. I prefer not to build speakers with standard box shapes. Even though I am completely satisfied, I still want to build this design to make that "what if" comparison. Anything over an 8 inch driver design in my audio room would be overkill.

So, I expect to be testing that set of speakers sometime in January of next year as well. It is really all about challenge. I just want to see how far this project can go. And of course, if I do order the latest Torii amplifier design, then this will also be factored in on future results. I am seriously considering it.  I would like an additional amp for another room anyway.  Of course that is not about to happen for at least a couple of years with the current rate of production on amplifiers.

Yes, I am curious about the latest generation of Torii amps. And I just may treat myself to the current model, but I really don't feel the need to do so. That will have to be one of those comparisons that I have to "experience" in my well balanced audio room, as a direct challenge to my current amp.

As I said before, I am always up for a good challenge, and I do want to know if I am really going to gain anything worthwhile enough to justify the huge cost. That remains to be heard, and I will tell you if I am taken to another level. I can assure you of one thing, if that gain is to be solidified within my mind, then this room is the ideal setting to make that happen.

Forget about the common factors of size ratios. I have gone way past that, making huge discoveries as to how great a small room can be when executed properly. It can be done, and I have proven that all too well. So much for what the "Audio Experts" would have you believe!

 And one more thing, I didn't have to remortgage my house in order to stuff my walls with activated carbon to achieve my goal. I do understand the theoretical approach to how that product works, and apparently, it works very well.  I just can't justify spending that much money for something of this purpose. And argue if you will, but I don't need it. I achieved my goal without it.  If the cost factor would have been more reasonable on bulk activated carbon, I actually did want to go this route. Looking back, I do not regret in any way making the choice I use now.

  I have not disclosed what my current system is and what it took to get me where I am at now in 2024. That will be in due time.  That is if enough interest is expressed within this thread. Hint: It is so great now that I am doubting the need for the Zrock3 for well produced recordings. I do have enough mediocre recordings that lack the depth, definition, spatial information, and especially dynamic range to justify the need for the unit. This in contrast to my properly mastered recordings which simply do not need reinforcement in my situation. But I am hoping that something special actually does transpire, even from these high quality selections. I can tell you that dynamic range with a deep bottom end is not something I would need help with on A list recordings. My current speakers produce an Fs of 27 Hz. and they are extremely efficient. I only require 30 percent of the volume control using the ToriiMk3 to bring these speakers at full levels of dynamic bliss!

When it feels like the drummer and bassist are on stage in front of you, that is when the system has my full attention.

Those dull recordings are the reason why I have this unit on order.  If all recordings did everything right like the ones in my A list, then there would simply be nothing to gain from the Zrock3, at least not that I could possibly imagine. But hey, I am up for the challenge. If there is any possible improvement on my A list recordings, then I am simply going to be so excited that I just may feel euphoric enough to remain in the audio room with the exception of necessary bathroom visits and the need for a meal and a cold drink.. There are some nights that everything sounds so fantastic, where I am almost to that point now. If I get punched any harder than what the dynamics of my system are doing to me now, then I may start developing bruises.....well, you know.....just a silly expression, but it certainly does come to mind.

 The only way to be sure is through listening.  I am very interested to find out what may be in store for me.

Again, the entire point of this whole experiment is to actually know the difference of how extreme measures can finally place me within a state of mind that I have nothing else to gain, and be completely confident with that acknowledgement.  I have made it to that advanced level of perception....finally!

I was not going to mention anything about all of this until later, but I think there needs to be some stimulation injected here before people go to sleep on me...LOL  

Hey there mrchipster, thanks for the very nice reply!

At least you didn't place any pressure upon me

Anyway, let me place a bit of input here regarding your inquiry made with some well respected questions.

Now as far as my skill and craftsmanship are concerned, I am very disciplined in my endeavors. I always place as much of my self into my projects as one could ever imagine. I like taking things to extreme measures. I also like to try things outside of the proverbial "box".  I have always been a believer in doing things as well as one can do, and if that fails, keep learning and keep pushing forward. That just seems to be a good strong relationship with life, and it always seems to work well for me.

I am sure that my upbringing had something to do with that. I came from a generation of those that have the passion to seek knowledge concerning things of great interest. When I was a kid, (the 60's), I remember being on our land out in the countryside. It was common for Air Force fighter aircraft to do low level passes across our farm. I now know that these included 107 Star-fighters, F-102 Delta Dagger's, and later on, A7 Corsair II. This observation ignited a passion within me to one day become a fighter pilot, something I desired more than anything as a result of those exhilarating flyovers.  The incredible shock waves as these jets streaked through the skies was something I could have never imagined without actually experiencing it.

That was a glorious decade with the developing space missions unfolding.  Experience transcends our knowledge straightforward into an admirable level of execution within our future. The Mercury missions leading up to the Apollo program became an extreme inspiration to Americans of that time period. I was always fascinated by technology and what was possible in the future.

Long story short, I was never allowed that opportunity to reach for the goal of being in control of those fascinating aircraft as my eyesight was below standards with strict denial of corrective lenses at that time. So that ended my dream as it became very clear this was not going to happen. I would have at least liked the opportunity to try. The washout rate is high, and many can't hack it. Very demanding both physically and mentally, not to mention the skills which must be acquired. A bachelor's degree is required just to get into OTS, (have to graduate as an officer first) then flight school....damn if that isn't a journey within itself!  

I remember being offered a chance to transfer into the army as a warrant officer if I passed combat helicopter training. The Army was needing to fill a shortage of chopper pilots, therefore scouting for candidates. Again, washout rate high, very difficult program to succeed in, and of course, flying a military helicopter is no easy task. The downside, if washed out of flight training, I am stuck in the army, and not for what I was hoping to achieve.  NO WAY was I going to risk that. I recall being stationed in Korea back in the early 80's, we were located very close to the DMZ. The army would occasionally land on our base with swarms of Bell attack Cobra's. That was a sight to behold and get swept up in. With the newly advanced Boeing AH-64 Apache, how could one not entertain the idea of being in control of that firepower!  Sure, it sounded like an interesting offer, but the stakes were high and I had to say no.

Anyway, my proud heritage as an American and to the country I served to protect, led me to the choice of serving the USAF because my family served, and it was my duty to do the same. Going back to my fascination with military fighter jets, I knew that I wanted to be involved with them technically since I was never going to have the chance of flight status, at least not as a pilot. I continued for almost nine years of active duty service learning and experiencing as much as I possibly could about aviation. It was a thrilling experience to be part of that. With a very specialized background and a high level security clearance, this provided a very interesting path into my civilian future. I will always have that state of mind. That is not something which can be erased after years of disciplined dedication to service. To have experienced first hand and up close highly sensitive projects such as the SR71 blackbird during the early 80's, and where this led up to future technology, very much summed up an achievement for which I am very honored to have been part of. This would have never happened had I never followed my dream as a young kid.

Even though I did not take the exact path of my childhood dream, I found a way to live that experience in an alternative way that was close enough to feel connected.

I suppose in some sense of the way, this seems to be a completely elaborate tangent off the path to relevance here, but I think it does form a pattern of what makes me think the way I do, and what force guides me with the inspiration to make something of interest happen. Why talk about it when I can actually make a difference. We all can if we take the initiative to follow through with what we desire.

Man, did I really just put you through all of that!  Sorry, this is what happens when I get to thinking, and memories flash back as if they just occurred.  I do think it helps for you to relate to who I am, and what drives me within endeavors such as acoustics.

Okay, enough of life history, let's move forward with what motivated me to take interest in acoustics.

 


Alright, back on track to your inquiry. I can look back to my journey involving the science of acoustics and why this field intrigued me into an inspirational lesson of the world around me. Actually, I had my first bizarre audio experience back in 1986 when I was stationed in Iceland (The 57 F.I.S. fighter interceptor squadron, the Black Knights), was that ever a fun time!

So imagine this, we have small rooms that are shared by two individuals. Not much space there, bunk beds, side closets, and some space for sitting inside of the room. That sounds horrific for a space that one would want to enjoy listening to a stereo. This is why there is actual significance to this situation.  I had my studio grade Akai 747 DBX type 1 reel to reel, my dual carver M-1.0t amps bridged mono, the carver 4000t Sonic Holography Auto-Correllation Preamplifier, and the Carver CD player all in this room. Believe it or not, I had double stacked Acoustic Research AR 98-LS speakers sitting up from the floor with stands against the back wall between the bunk beds and the closets. I also had the DBX RTA (real time analysis)10/20 computerized graphic equalizer and room analyzer with a pink noise generator and calibrated microphone to set the rooms best response curve. That was quite the system for the day!

So after setting the response curve to as "optimal as possible" with the pink noise generator, and utilizing the Sonic Holographic Setting on the 4000t, I recall something that simply stunned me as I had never experienced anything like what was about to happen, ( I can assure you that this was the result of these two units creating this magic). Some recordings have special effects placed into them from the mastering process which can have strange phasing upon playback as intended by the technician, this creating a three dimensional illusion. The soundtrack I am about to play I have heard many times on other systems. I can assure you that this track never sounded anything like this. I played The Eurythmics track : Like A Ball And Chain. During this song, a huge trail of wind surges through the air as an imaginary "ball" going in complete circles around my head, with a distance which seemed to extend way beyond the limits of the room.  This really took my senses and shook them up a bit. I just could not believe what I just heard. It really seemed as if this ball was going completely around my head. I think I even looked around as if I expected the ball to be real. The three dimensional illusion was very real!

Now mind you, this took place in a very small room which should sound like total garbage acoustically. Normally, that would have been the case, but the RTA saved the day with real time monitoring and response calibration.

Hint, that alone should relate to some sort of significance as to why room size is not always the deciding factor in acoustic perception of a larger space.

A couple of other prime examples which many audiophiles relate to are two recordings by Pink Floyd. The Dark Side Of The Moon, and my favorite, Wish You Were Here.  Oh, it gets really good here! As a prelude to "Time", there are two rows of various clocks set within the soundtrack. Any fan knows what I am referring to. Usually, this sounds just like a direct two dimensional spread in front of the listener. What I experience is much different, and far more interesting.

I am sure that the recording engineer ( I believe that was Alan Parsons), intended for this spacey floating effect of the clocks ticking, and alarms going off throughout the listening space to be realized within a wide dimensional aspect, but most systems  do not actually convey this special effect. For the system I was hearing this on now, things were about to change radically for me in how this was about to unfold in a whole new dimension. With my eyes closed as to not allow my perception of sight to influence my perception of time and space, I let this illusion unfold around me as if I had just discovered something completely beyond comprehension.

These were no longer two direct rows of clocks spaced in close proximity. Now, these clocks with pinpoint accuracy and sense of complete reality just began to float around me, as if some were stationary in high corners of the room, others as if in the middle, and then those that seemed to drift all in between, and also beyond to what seemed to the far rear sides of my head. The sound of the gears turning, the ticking of time, and the mesmerizing chime of the alarms going off in unison.  Yeah, it really did take me to a much higher level of audio experience. I certainly was baffled as to how this was possible in such a small room, regardless of the electronic enhancements being utilized. Then came that fantastic intro of "Welcome To The Machine" on the Wish You Were Here album. An EMS VCS3 synthesizer was used to create these effects which just lure you into the image of being there on this imaginary journey. The corridors of air lock doors as you would be lured through from one corridor to another is very convincing if you hear it the way it was intended to be heard. You definitely need a system capable of very low frequency response and a healthy supply of power to appreciate this title.

So into the future, back in the USA around 1989, I separated from the military and was now a civilian again. I decided to sell some of my gear for some extra cash to start over again. Unfortunately that decision included the DBX RTA and my superb Akai 747 reel to reel which I still regret today. I did purchase a new set of Carver "Amazing Loudspeakers" in the late 80's.

(A two-way hybrid with a ribbon operating full-range above about 100Hz, and a dipole bass system featuring four 12" woofers in a finite baffle loading. Nominal impedance: 6 ohms. Sensitivity: 88dB/1W/1m. Maximum SPL: 113dB symphonic music, 110dB rock music.)

I continued to drive these with the twin M-1.0t amps bridged mono, and the 4000t holographic pre-amp.  These giant dipole speakers laid back at a 5 degree rake, sounded very open and detailed. Even though I had sold the very piece of equipment which really made the three dimensional perception the most revealing, I was still getting a robust three dimensional spread from these large baffle speakers. As you can imagine from the low sensitivity rating, these demanded very large reserves of power to drive. When that power was delivered, these really hit hard with the low frequency content. Of course the huge array of ribbon elements is what made these speakers sound very good. With this new system, I still brought out some very interesting information from the music in three dimensional space, but never like I experienced with the real time analyzer.

So I accepted things as they were at that time and let it be. I was now building up a decent home theater system so there were some new toys being introduced for that purpose. I had a set of small NHT speakers on pedestals used for the front mains.

Now one day, I decided to experiment in a larger open room. I wanted to utilize the old solid barrier technique with the speakers placed directly on each side of this solid barrier (3/4 inch plywood or MDF). This technique was used to reveal how ambio-phonics worked and sounded in binaural fashion. This separates and removes the unwanted binaural cross-talk from the speakers, therefore eliminating the ear-brain confusion one gets with this detrimental flaw in a normal stereo configuration of the loudspeakers. Now this is only intended as an experiment to provide the listener with what happens when this binaural cross-talk is removed from the speakers. I certainly would not take to listening like this all of the time, as nobody would. Due to the fact that you must have your nose directly at the edge of the barrier to be able to perceive this effect in full form is the only reason necessary to know that this form of listening is not practical or even remotely warranted as a sane thing to do. I could just imagine my wife walking in and seeing me do that.  Pretty sure she would be convinced that I have lost it!  


But what happens as a result is simply mesmerizing, the truth reveals itself, and for the first time, you actually experience what has been suppressed within the music on normal stereo playback. The audio truth had set me free, and I knew this was a newer level of standard that I must achieve if I am ever going to be satisfied with my listening experience using a stereo set of speakers again.

So in this experiment, I simply had the speakers, the barrier, and for amplification, I used my Sunfire Signature Grand 5.1 surround amp in stereo mode.  During this time period, I had a set of Decware SET mono-blocks with the radial speakers, a Teres turntable, and a ARCAM Alpha 9 CD player with the Ring DAC.  I can assure you that even though that combination sounded very nice, it simply was not producing the effect I required from a system. I knew that huge tailoring of room acoustics was the only hope of doing so.  

This story continues on...I shall have to post again to proceed. Sorry for going off the deep end...very typical of my story telling.
 

Hello Gilf, thank you. That was certainly an interesting time in my life.

So yes, I completely get your point concerning the separation of work and play. This is like a full time chef who slaves to keep his restaurant profitable as he spends countless hours doing so.  I can imagine the desire for making his own meal became a burden after awhile.  probably had a great deal of ready made dinners...or someone else prepared his meals.



Funny you should mention the studio within your home. I realized that my audio room could very well be used for making high quality recordings as if it were a studio built for that purpose. There are very close parallels between the two room requirements. Although a room built just for listening does not have to be soundproof like a studio, but it sure does help. The one common thread between the two rooms is acoustics. That remains a constant for great music, whether recording or playback.

You did start off with a very solid platform for which a dedicated listening room can shine it's brightest. I am sure most people have not gone that far. Sounds like the studio you built would sound very good with the proper treatment of course. I am sure that you had that covered very well being a professional working environment.

I would like to mention one thing that stands out about my room when you walk in for the first time.  I have a feeling that your studio gave the same vibe.  After sitting down with the airtight door locked, I remember the first time I actually did this and just sat there marveling at how peaceful and serene the feeling of this space was.  I found it immediately relaxing and soooo very, very quiet!  I actually thought I could hear the blood flowing in my ears...so the level of blackness within the room paid off with all of the treatment and acoustic sealant.  I just knew that music was going to sound great in here.  You know, I may have been on to something.

I do thank you for chiming in here and conveying your story. I think that the scenario you provided helps to formulate just how influential these types of changes make to a good listening room/studio within the minds of those just learning about acoustics.

I am glad that you found solace within your music after such a long departure with music as a sense of enjoyment.  Kind of reminds me of a call girl's lifestyle....just can't take her work home with her..  

The only thing that really matters is that you are satisfied and completely content with your situation now. If we could all be like that, there might be some extra cash in the bank.

Of course I will be going in-depth on the principle of design factors within the basis for a binary diffuser/absorber. Yes, out of all the enhancements that I have ever introduced into an audio room concerning frequency tailoring through diffusion, I can easily say without reservation that this concept gives a far greater return on investment than any other "quadratic" system that I have used in a medium to small room. Now as far as large spaces go (3500 cu feet ), and larger, I would begin the  optimal choice of prime number quadratic diffusers. A room smaller than this proves to be advantageous by using the binary methods. The smaller the room, the more this becomes fact. And that is quite the standard to compare against. I have built many large scale custom prime number sequence quadratic diffusers based upon Schroeder's concepts which were refined by RPG when they were still around with D'Antonio being the lead designer.  Dr. Peter D'Antonio is a diffraction physicist, who lead the way for the sound diffusion industry at RPG. Everything that I learned about acoustics derived from the work of Dr. D'Antonio and Trevor Cox who is a Professor of Acoustic Engineering at the University of Salford.

The real core of acoustic engineering goes back to Manfred Schroeder, a famous German physicist who contributed greatly to the world of acoustic engineering and number theory relating to this complex science. Much of what you read within the Master Handbook Of Acoustics is based upon Schroeder's work. The very core of what my binary and ternary diffuser concepts stem from derives from the actual retail models developed at RPG by Dr. D'Antonio as the primary physicist. These huge panels are well known for what they do for acoustics in a music room and are very respected as such. What is really needed is the base model showing the starting number sequence as refined by extremely complex computer programs specializing in number theory.  That complex sequence is a highly refined code which forms the basis of the large scale EXPO panels.  This design goes way beyond the simplicity of the original BAD panel, being far more advanced. If you notice, there are so many small so called acoustic companies which are merely cloning these designs and selling them as their own products. So much for patent protection! I wonder how many of these copycat sellers are paying  the actual inventors of these concepts which should be getting royalties out of their work. Perhaps they are, but I really doubt it.  I am thinking that most of these small companies in reality, most likely do not even understand the actual design theory that went into this complex engineering. You can't put anything out these days without someone copying the design, and making money from it. At least I keep this design for educational and personal use only. I have never tried to mass produce this technology, or even make a single dime from it. That would be wrong to do so and I respect the intellectual property that belongs to the designer  who patented it.  I could share the technology revealing the design pattern, along with variations for which to expand and build even greater models that actually work. But that is the extent of that sharing.  This information is widely available on the internet, so I am not revealing anything that has not been already revealed by the contents of the patent to the public.

One more thing that I have noticed about these sellers on the internet, I don't see them producing and selling copycat cloned models based upon Ternary and Quaternary number theory. I am sure that if there were an abundance of design blueprints available for them to copy, those models too would be replicated and sold wide-scale.  So far as I can tell, this is mainly being done with the binary systems, but give it time, the next generation will follow. I was experimenting with binary panels long before these "fly by night" companies began selling them online. When I had my YouTube channel for acoustics, I had thousands upon thousands of hits for videos based upon the design and build of these units. They would not support my channel as subscribers, just too lazy to even click a button for free material! However, I gave away a goldmine of information that never gave me a return on my investment. I absolutely despise that whole YouTube concept. They have become so greedy and controlling of the studio contributors that it is senseless to keep allowing them to profit from our hard work while we get nothing back from it. Very few contributors actually make a good living based upon YouTube profits. It takes a huge degree of subscribers and viewing hours to qualify for compensation. In the mean time, YouTube plasters garbage advertisements all over the video which really distracts from the content. I quickly had enough of that unfair practice. I soon pulled the plug on that scam operation and removed all of my videos from public viewing.

I actually had some guy with the nerve to ask me if I could tell him a certain measurement for building the EXPO panel clone. This was after I removed the video from public eye. He actually stated that he needed this to put these plans into mass scale production of the work I provided.  How much do you think I was going to profit from that!  Needless to say, he never got what he was seeking. I made it very clear in my videos that these designs were legally patented, and were not allowed for reproduction in a profitable way without the consent of the designer. As you may surmise, nobody seems to care about that, and I know the Chinese manufacturers are not concerned with this. Unless the designer is willing to take these people to court, then they simply get away with it.

On a good note, I received compliments from many who actually built this design as I instructed, and it was obvious the level of interest involved within this design. I had a response from one guy who had built the binary modules as I instructed. He was very excited about what he gained from this concept and stated that he never thought it could be possible for something like this to make such a huge difference in overall music perception. According to him, he had tried many variations of diffusers and absorbers within his room prior to trying my models.

I forget the exact quote, but he stated something along the lines of "whoever is responsible for this design is an absolute genius! The ambience and spatial properties of this room have unfolded ten times over, revealing things within the music I never knew existed."  

Well, what can one say to that?  At least this guy took the time to let me know how these improved his audio room.  He was specifically referring to the suspended full scale modules which covered his ceiling the same way mine is done. Just suspending them from the ceiling alone made that much of a difference.  He informed me that there were to be many more modules built and installed along his entire room.  So you see, there is hope for a small room with this concept. It works, and many have proved it.


When you realize what one of these panels are worth retail, you quickly see why it is advantageous to construct your own. Once the pattern is established, it is best to let a CNC shop produce these quickly and with great accuracy. These need to be constructed out of high mass material with substantial thickness. I would never use anything less than 1/2 inch plywood or MDF. It is also about the type of acoustic material which layers behind this panel which signifies it's acoustic signature. This design works by an even balance of diffusion and absorption. If the absorptive factors fail to perform correctly, then the entire module fails to reach it's potential. The design parameters are extremely critical, with a level of deviation not allowable if guidelines are not held within strict tolerance.

What I did to make my EXPO based panels unique, and still adhere to the strict code within the number sequence, was to employ a variation of inversion and rotation tactics with the base sequence. I continued to expand this concept until the dimensions of my panel were filled. If you look at the pattern closely, you can see just how uniform the spread of this sequence becomes while maintaining a constant degree of variations with strict adherence to the primary number sequence. This expansion can go on infinitely as long as the proper implementation of rotation and inversion is adhered to.

I will be going in depth about the construction of these binary difuser/absorber modules which are 4 ft x 8 ft panel size. That will come once I get into the diffusion tactics of my audio room build.  As a bonus, you may even learn what a Ternary diffuser is and how to build one!

Evidently my previous post never got 'posted' earlier when I wrote it. Must not have hit 'post' hard enough I guess ... lol... that was in response to your post #73.

Re-reading your latest post now.

Speaking of DSOTM, I recall hearing that album for the first time on a truly hifi system. That introduction heartbeat begins in the systole phase and emerges from the front center, passes through your body, and hits the back wall, and diastole phase returns from the back wall through your body again and returns to the front center, at which point the reverb washes both left and right all around you until the next beat. It is truly a reference for room treatment, imaging, and room pressurization.

That introduction heartbeat begins in the systole phase and emerges from the front center, passes through your body, and hits the back wall, and diastole phase returns from the back wall through your body again and returns to the front center, at which point the reverb washes both left and right all around you until the next beat.

Now we are on the same sheet of music playing in harmony.  This is exactly what I am referring to. You get what I am trying to achieve. I need to bring out those effects the way the engineer created it for me to experience. When I listened to this album many years ago with the sonic holographic circuit engaged, and the speakers almost completely together with a panel in between them to act as a barrier centered directly in front of me (the experiment to eliminate cross talk), there were a few more things of interest that came out of this set up.

As the man in that segment is running from whatever is chasing him, the sound stage has him coming around from a far distance on one side, then swing around wide to the other side, running in a circle behind me, back to the other side until he fades away in the distance. The sound chasing him then passes over and behind me  with a very realistic sense of passing overhead. Then it is heard crashing in the background behind me as if it were a mile away.

From that point on, I knew this was an audiophile reference soundtrack to gauge the worth of a sound system. Anything that can accurately produce these effects is the exact thing that spells 100 % success for me. If a system and room fails to produce what is on this album as I know it should be, then this audio room is simply not up to the standard I desire.  Now that we understand each other as to what my goals and expectations are with my current room, it is much easier to convey what I am doing this all for, and what I hope to achieve.

Gilf,

I've heard that tune many times and always thought it sounded good. But your description made me realize what it should actually sound like. Red pill is trying to get us closer to that realization.
Fantastic description of that sound sequence.

As close as headphones can come to conveying the music/space/realism, being able to be surrounded by it in a physical room in space is where it's at for me.

After college I hired on with IBM and spent 31 years there as part of a team designing integrated circuits

So I see that things really did work out for you.  I can't imagine a better success story than that for someone getting back on the track they desire.  Congrats on that!

I now see what you were talking about concerning the modified F-5 trainer.  That makes much more sense to me. Now as far as a Boeing 747 modified with weapons systems...hmmm, do you think the AF ever considered that? Hey, a cheaper alternative to the B1-B  bomber!  

My final duty station was Grand Forks, ND after returning from Iceland. Strategic Air Command finally got their claws into me and would not let go.  Because of my rank and skill level at the time, I was prime for the brand new B1-B's replacing the old B-52's. Because of the $billion price tag on each bomber, they wanted only people that were best qualified to work on that aircraft. They required a minimum rank of Master Sergeant just to be a lead crew chief. Usually, the assistant crew leader was a Technical Sergeant or higher. I also had to pass a very high level security clearance to be accepted.  We had continually changing security pass-codes that had to be learned each week. If you did not give the proper response, A lesson about paying attention quickly unraveled as a  reminder of how important this is. The security police would quickly get you on the ground under arrest. They had no problem putting a bullet in your head if you gave them a reason to.  They did not play games here. Live nukes loaded on the ready line aircraft were a very serious thing, and they don't take chances.  Nothing like the feeling of several cold rifle barrels at the back of your neck if you screw up! Luckily, I never screwed up. It made a person quite tense, and a bit nervous to go through that gate.

Let me tell you, living in that baron desolate place made Iceland look like the Bahamas by comparison. We always claimed how many winters we survived there as opposed to years. Those winter's were brutal and long!  I was locked in to this program permanently and was told it would be until I retire. Another 10 years in that hell hole was not in my future, so I knew I had to terminate and get out of there as soon as I could.  Because I was now part of a very sensitive nuclear strike force with the sole purpose of counter striking the Soviet Union during the cold war, this location would have been permanent.

You would have had a fun time loading those nukes into the huge dispensers in the bomb bays.  Those pilots knew they were on a one way mission if ever on the way to deliver a nuclear payload.  After all, what was there to come back to?  And of course there is that flight capacity with limited fuel on the return. Without being greeted by a KC-135 (airborne fuel station) to top off, that would have been impossible. The cockpits had heavy lead-lined curtains and protective enhancements to help shield the initial blast of the nukes  after delivery. I can assure you, mutual destruction would have been met ten fold.  That is the very sense of logical reasoning that kept us out of a nuclear war.  Peace through mutual power.

Most civilians have NO idea how many times that threat came close to reality.

So anyway, back to the future.  I have to get off of that track, and focus upon the reason for being here now..that is acoustics.  We could chat about that past all day, but that derails the main content. We could really conjure up some memories dealing with that era.

One more thing concerning concerts. I had experienced a great deal of them in the 70's and 80's, but I tell you this, nothing compared to the live Pink Floyd shows, as these completely stood out from the rest. Only someone who has actually experienced these shows realizes what I am talking about. If you were a fan of their music, then you HAD to see them live to get the total experience. I will never forget those times. They are as vivid as the night they happened.  Just look at the grand scale which Roger Waters put on a special concert event at the Berlin Wall location celebrating its tear down.  That was the most incredible event one could imagine. The expertise, the cost, and the work that went into making that event happen was quite the challenge. Waters did not fail to relive "The Wall" tours during that night, and at a much larger scale. Seeing it on DVD is one thing, but being there brings a whole new dimension to it.

Now THAT was an example of GREAT acoustics!        


 As for small clubs, there is something to be said about that intimate type of atmosphere.  When I lived in Austin, TX., going down to Sixth Street on the weekends was very special. You could just jump from one club to another to see various comedy routines or to see many up and coming musicians, or already popular musicians playing in these small clubs.  This reminds me of my time on the Florida Gulf Coast where I spent some good times partying on the beach. It was common for major groups such as 38 Special, Foreigner, etc... to play at the beach clubs during the early 90's. Such great times! Things were so much better then.  And did I mention Stevie Ray Vaughn, Robin Trower and the likes? Yes, they were a big part of that time. I still remember hearing the news live detailing the loss of SRV when Eric Clapton's helicopter went down. Eric was not aboard, but Stevie was unfortunately.  That was the end of a VERY promising musician. He was heading into superstardom at supersonic speed. I loved his style of playing. He was truly a naturally talented guitar player who inspired so many to follow. I can imagine SRV and Hendrix playing together as the great gig in the sky!  One day, "slowhand" Eric will reunite with them and play into eternity.

And in memory of two greats who will never be matched for what they accomplished, we shall not forget Eddie Van Halen and Neil Peart for what these legends contributed to the world of music.  Seeing Neil play drums is mind boggling. I saw him play several times. All I can say is that Rush was very lucky to have had him as a drummer. As for Eddie, he was a rock legend, what more needs to be said. And to the final departure of the original Lynyrd Skynyrd, you guys did it the right way, playing the likes of "Freebird" into eternity. It was a bit sad to see Gary Rossington being the last member to finally pass on. So much success, so much tragic! Sometimes the price is just a bit too high.

I just may request "freebird" be played at my funeral to send me on the great journey into the unknown.  "TURN IT UP"    



Now, it is time to get a bit closer to the music within our control. Please stay tuned, there is much more to follow.

Totally agree with you when it comes to live shows, especially Pink Floyd. I was lucky to see them twice. I'll never forget those live performances, for many reasons.

If I need to go to a larger venue (civic center, etc.) to see a band I really, really like I will, but so far I have been seeking out the smaller venues, mainly for the reasons we're discussing here: Acoustics!
Living here on the southwest Florida coast not too far from Tampa and St. Pete there are many options.
I get to see great bands in theater-like settings, where the music and acoustics are paramount to me. Just like you're showing us here, the room can potentially make or break a great performance.

Nice pics from your latest post. Really starting to come together and it really gives us a sense of how much work and effort went into this. Not that I couldn't tell from the beginning but man o' man this is all out.

I have a few more pics of the framing assembly stage prior to stuffing with rock-wool and installing the wall layers.




A look at the doors installed while in rough form. You can see that everything is close tolerance with airtight design factors always being the major concern.  Remember, if air can pass through, so will sound.



A view of the second layer of rock-wool in the center divider between the closet spaces. The next step here is to install the first wall layer which is 1/2 inch OSB.






At this stage, you see the MDF framework within each wall module. These modules will become the diaphragmatic absorbers with metal face plates.



The blank speaker array panels are temporarily installed to check fit prior to taking them back out for machining.



The space for the floating speaker array within this cradle gets a layer of Quiet Walk flooring underlay as a gasket prior to installing the MDF frame.




The speaker array panel being test fitted within the floating cradle prior to machining.




This view shows the cardboard retainers installed within the modules which support the rock wool in order to maintain a proper airspace between the metal panel and the rock wool.













































































I will be back next time to show the installation of these speaker array panels within the baffle wall. Following that, the next step is to install the rock-wool and then the metal face plates.

RockWool has the ideal density and absorption rating for this particular requirement. It is easy to work with, cuts cleanly, and is much safer for exposure than using pink fiberglass. I still suggest wearing a face mask and gloves when handling.





Review this chart and you can compare the airflow resistivity of RockWool, and fiberglass insulation. As you can see, there is a substantial difference in airflow resistivity between the two.  Fiberglass has its place in certain applications, but here, the Roxul is favored for better absorption and resistance overall.






Now it is just a simple task of inserting the Roxul behind the support straps to hold it in place.




























You will notice that I have set the distance of the Roxul backward enough to allow a degree of airspace between the insulation and the metal face plate. This is absolutely critical for the effectiveness of the diaphragmatic action to function properly. The thicker the insulation ( along with the properties of the insulation used), along with the degree of airspace, actually determines the level of absorption and airflow resistivity attained in the end result.  This particular application is very useful for midrange to lower midrange absorption. Unfortunately, this is not deep enough to absorb energy within the low frequency registers.  That task is left up to the huge bass absorbers which are built for that purpose.





Take a look at the detail and you will notice that there must be a provision for the sheet metal face plate to be attached and still maintain a flush setting within the baffle wall. The goal is to have the metal face and the surrounding wall be seamless after the finish is applied.  The metal gets attached to the MDF frame using only sealant as an adhesive. If these panels leak air around the perimeter, the diaphragmatic action will fail. This unit acts like a spring, slowing down the energy passing through it, while absorbing much of this by heat and dissipation.





The effectiveness of this wall assembly is very beneficial in it's ability to slow down energy hitting it from the return bounce of the room itself. The reflections are reduced in amplitude as the sound waves hit the metal plates of the diaphragmatic absorber modules which are working at different levels of sound reduction by the size of each unit. The return rate of energy back into the room is greatly retarded in size and speed. That difference in time and space is the very thing that helps to create a more spacious and less restrictive room. The end goal of any audio room is to (remove the boundaries of the room to the point where the room itself is no longer a noticeable part of the equation).  This is how we make a small room sound like a much larger space while maintaining a live and natural purity to its final form.































It is necessary to install additional support straps with the larger sections of Roxul to keep it securely in place. We absolutely do NOT want this insulation to become relaxed and bow in the center. If that happens, it leans against the metal face-plate and thus resulting in failure of the unit to be effective. Heavy duty cardboard works great and it is free.  I used a heavy duty stapler to attach them to the MDF.










This full scale baffle wall is now ready for the metal face-plates to be installed.