So today is a no go for roofing. The rain has been relentless and is expected to continue through tonight.  So I shall post some more images here now while I have the time.


We left off with the window modifications. I shall pick up with that now.


Here is the backside of a window cover showing the airtight seal which goes against the full frame. Because of the size and weight of these panels, I had to do this in two sections to make them manageable.

























































That pretty much "covers" up the side window. As you can see, it is very easy and quick to remove these covers. Whether it be just needing some fresh air, or an emergency egress, this system allows for both when needed. If ever reverted back to a normal window frame, just remove the threaded posts and install regular window curtains. This window however, is far better sealed and airtight than it was before.  A great deal of external sound came through these original window frames. Now, only the loudest of sounds can be heard, but at such a reduced level, it is easy to ignore. I don't get that much noise around here anyway, so not really a problem. At night, it is really quiet around here.  Just after midnight when the Amazon fleet of 767's fly overhead to unload cargo at the airport does that noise level pick up. Even that is low enough that even normal listening levels are not hampered.


I will go over the modification detail with the front window facing the street next.

The floor is carefully examined for any remaining staples after the carpet and padding was removed.  All nails must be flush before the underlayment is laid down.  The seams are sealed, and covered with heavy duty tape.








The laminate flooring is very thick at 12 mm. Along with the Quiet Walk under-layment, this flooring provides a nice sound barrier while providing a hard reflective surface which is ideal for this room. The goal is to not over-saturate the room with carpet which is more detrimental to the sound of the room than having a reflective surface.  Carpet only destroys higher frequencies which we absolutely want to preserve. If you want to maintain a live vibrant space, this is the way to do it. The focus needs to be on the ceiling and all four walls to combat against reflections, and standing waves.

We know that standing waves are created by the buildup of nodes and anti nodes dispersed around the room. Destructive interference creates nodes, while Constructive interference is responsible for the buildup of anti-nodes. When two waves traveling in opposite directions collide, the result is anti-phase cancellation.  This is why low frequency absorption is so critical to bring this problem under control. The lower the frequency, the more difficult to control. As the frequency gets lower, so does the length of the sound wave.  These problematic waves require bass absorbers that are either extremely deep and large in size, or by means of mechanical function such as diaphragmatic units which reduce these waves with heat and dissipation.

So you see, that thin carpet is going to have absolutely zero effect upon the lower frequencies that need to be controlled. Let the massive bass absorbers do that job. Even the most massive units are limited in how much they reduce standing waves.  It should be clear by now as to why it is not a good idea to have carpet and padding on the floor.  The large reflective surface maintained by the flooring provides you with the ability to fine tune the rooms balance between the low end, and the high end of the frequency spectrum. If you lose that control, the room will simply be dead, and far from what you desire in an audio room.

This practice of balance is extremely delicate to deal with.  This is why binary diffusion/absorption principles work so very well within a room this size. It is really a 50/50 balancing act that keeps things in perspective. Unless you have at least ten feet between you and a quadratic diffuser, this type of diffusion is not a good choice compared to the binary and ternary alternatives. They work with distances as short as three feet from the listening position. Now you see why they are the ultimate choice for a small room. Once you listen in a room treated this way, you will quickly understand once it is experienced.

There needs to be huge amounts of absorption within the room to counter and balance this effect. The trick is to provide this degree of absorption without creating a dead environment. There already exists the possibility of using so much absorption that the end result creates a dead room which is as bad as an overly reverberate room. There has to be a certain degree of reflective surface to keep things in check. Unless the absorptive material has the ability to slow down low frequencies, it is best left out of the room.

Perhaps it's use for random spot treatment might be desirable, but then again, maybe not at all necessary. Use the floor to walk on, and take care of everything else with corrective measures. What you do to the ceiling and walls are what matters the most.

I'm telling you from firsthand experience. I can assure you that this is a good rule to go by, one that won't disappoint you. The end results I am getting with this room are far better than what anyone would imagine for a room this size. Your ears are very good detectors of this fact. I am extremely satisfied with the acoustic signature of this room, leaving nothing in question.  This of course is the same room that before any modifications were done, was a space that was unbearable to use as a music room.  This room was horrible before I transformed it. Everything sounded bad and I could not listen to music in here. Now, that is completely the opposite situation.





































This is a floating floor which has no mechanical fasteners what so ever. This is why this type of flooring requires a minimal space around the perimeter to compensate for movement.












This is the modified air return intake for the room. This leads through a hush box hidden between the dual leaf walls and sealed to the floor where the original intake was located.



















It is time to start building the acoustic control devices for this room. I shall start with the ceiling.

Hey JB,

Thanks. Yes, this system does work very effectively, and it is simple to create at a very low cost factor. The really good thing about it is that it is completely reversible for regular window dressings if desired.

Most common noise is during the daytime anyway. After 8:00 PM, it is very quiet in this area. Just the occasional freight train in the distance and Amazon flying overhead between midnight and 2:00 AM. After these Boeing 767 freighters pass over my house, they are on approach to the runway just 8 miles away from here.  I hear them flyover, but the level of noise is acceptable when they do, roughly a third of what the noise level would be without the window covers. I find that to be very good for my needs.  Actually, I think about half of what I do hear is coming through the roof above the room.

Now for studio purposes, that would still be a problem. I for one usually am going to bed by this time, so no problem at all for me.

Even so, when I am sending a good flow of juice from my ToriMK3 to my speakers, I can assure you, I am totally oblivious to any of this while listening to music anyway.

All is good.

Schroeder presented a folding technique referred to as the Chinese Remainder Theorem. This technique was applied to phase grating diffusers based on poly-phase sequences.

This same technique became the basis for a binary hybrid diffuser.  A 1d sequence is folded into a 2D array in order to provide a hemispherical dimension with the ability to preserve critical auto-covariance properties within the design.


This is a base one dimensional sequence for a binary diffuser. This sequence is then converted into a more complex two dimensional array for which my panels are based on.






This became the final result of that folding sequence which expanded the simple one dimensional model into the complex 2d model. The pattern shown is one full 2d sequence in this hybrid binary design.




According to the patent information, the following graph shows the performance curves for comparing the binary, ternary, & quadra-phase diffusers utilizing a BEM model to obtain the predicted absorption coefficients for each type of diffusive surface. These are prediction estimates.





The actual absorption material used for these diffuser models regulates the effect of absorption gained within the low frequency response for each.

The high frequency absorption coefficient is a factor determined by the open area of essentially 0.5.  This design follows the characteristics of a perforated resonant absorber. The peak absorption rate falls within the mid frequency bands.


There is similarity of the scattering produced between the unipolar binary and ternary diffusers based at even multiples. However, at odd multiples, the ternary diffuser provides improved scattering with a greater reduction of specular lobing.




Showing this three dimensional grid view of the finished layout, this provides a very good perception of how this complex code looks visually. You can see the developing pattern over the broad spectrum. The individual squares are the culmination of repetitive inversion and rotation tactics with the base sequence.      




Another view of this from a different perspective.




 

View of shop VAC routed through a dust collection system.




Don't forget the orbital sander.






View looking down over my custom d.i.y. drilling rig made from spare parts and material.





A rear view of the drilling rig.





This platform is extremely stable and solid. The drilling accuracy is dead on every time. The spring loaded glide rail system works very smoothly and with great ease.





The design of this platform which I created is very easy to use repetitively. It takes very little effort to operate this drilling rig as you don't have the weight of the drill causing fatigue in your hand. You will always drill straight perfect holes without worry.





It is paramount that you set up the accuracy of your drill very carefully. It is a good idea to occasional spot check the position of the bit and never assume anything.








You are set to get started.    HAPPY DRILLING!

A look at the required mounting hardware for suspending this full scale absorber/diffuser module from the ceiling.

There will be six attachment points with a load rating of 100 pounds for each connection point. That is a total of 600 pounds holding power. This unit when stuffed with four layers of Ultra Touch Denim insulation will weigh in at around 85 to 90 pounds. So you see, the strength of the suspension system is far greater than the actual load. The hooks are tightly embedded into the ceiling joists which go into the attic above the audio room. They are threaded deeply within hardwood. There is absolutely zero chance they will break loose or have any undue stress at all.  To top that off for extra measure, each and every connection point has a fail safe design where there is a primary and a secondary steel connector holding it very securely. Even if any did fail, there are 5 more with 5 more back-up points to keep things safe.  These have been suspended in my room now for several years.  They have not fallen on my head yet!





































































You see the clearance that I maintained under the cross support bar which is bolted directly to the binary panel to prevent bowing under weight. This allows for several layers of the denim insulation to fit snugly underneath the bar.  Once the unit is hung, there will be another layer of absorbent material placed across the top.































The chain links fit nicely around the mounting screw. They will not slip off, but they do have enough slack to swivel easily. These screws are heavy duty and they penetrate completely through the center bar.














Here you can see the mounting configuration which details the double hook safety backup. These attach points are connected to two critical anchor points and act as a backup to each other in case one fails for some very unlikely reason. The integrity of this setup is way overbuilt to withstand much higher levels of force. This will never be a safety issue.
















Now that the hardware is all installed and this unit is ready to be hung in place, the last thing to do is layer the denim insulation within the bed.

Before that is done, this unit needs sanding and paint.



Next I will show the installation of the absorbent material.