NP GS.  Loving your base thread.

Hi Steve, is there a design to follow for the internal diffusers in the Headwrecker?  Also, a newbie question: how do you secure the baffle to the speaker cabinet since you can't get to the back of the baffle. What hardware works best for that?  Thanks for a great design and for your support to us diyers.

Dave

+2

Hello everyone,
Slowly and painstakingly; relying on my rudimentary carpentry skills;   I am building speakers for P10 drivers based on Steve’s DFH Plans.
What is the best way to fix craft felt and foam to the panels inside to properly secure them?  Do I just use wood glue or nail them?

Thank you
Mamuka

I agree with 4krow!
Any time I have added compressed woven felt to the inside of an enclosure with wood glue, it absorbed too deeply into the felt and turned 1/4 inch felt into about 1/8 inch depth.
Then the glue hardens and you have almost like the wood itself where the glue absorbed too deeply into the felt, making the felt less effective.

I have used 3M Super 77 spray contact adhesive with much greater success.
Don't even need much on the felt.
I don't bother with staples or nails for this.

3M 77 Super spray adhesive is the stickiest stuff I have ever seen.  It will stick anything.  And it's cured in two minutes or less - make sure you have everything where you want it before you join the parts... because in about 60 seconds you ain't moving it without tearing something.
It's kind of like "duct tape" you never want to be without it.

**tip #1: for least stick, only spray one of the two surfaces to be joined.  If you really want them stuck - spray both surfaces, wait 30 seconds and press them together.  

**tip #2:  make sure you turn the can upside down after each use and spray a little propellent out to clear the nozzle - to avoid a clog next use.

You guys are all correct. 3M Super 77 is really a strong, dependable adhesive.
I figure if you guys are out there building Steve's latest creation, then you are in this for real and not just playing here.

I suppose I could have added a caveat, a yeah but and a what if regarding this powerful product before recommending it.
A what if might be that if you have no experience using contact cement, then get some before you try it on your carefully sawn to fit pieces.

It is the best contact cement I have used and even works as NOT a contact cement if you need. Using it as just a spray on glue, you have thirty or forty seconds to reposition things if you need - quite unlike using it as a contact cement.

3M also makes a heat activated contact cement, where you smear it on and allow it to dry. (takes a long time to dry sufficiently)
Then you can place things and reposition them until they are just right, tack them in place. It won't stick yet. This product does not bind until you use heat to activate the bond.

Sorry, I can't remember the catalog designation of that product right now, but it has proven to me to be inconvenient for internal speaker enclosure use.
It works better as an edge binding for veneer along a plywood edge or applying cork joint seals on woodwind tenons.

My Headwrecker journey has been long but it looks like they will be finished by mid February.

As a recap...I got many quotes for the cabinet builds from 18K$ to finally 2K$ each box from my Amish kitchen builders. They have a new Bessie CNC and will include paint work. The design is modified to use rabbet slots for the internal bracing, this will make the glue up easy. I also modified the diffusers to be acoustic foam I has from a studio build. The internal pillow is same as what Steve used. The paint is SkuffX midnight black satin. I almost added casters but decided against it because they would ruin  the wood floors so I'll use sliders. I am going to put the wiring terminals in the front as Steve did and probably use the wings because my room is long. Needless to say the anticipation is exciting and I'll be using the UFO amp and also try the R8. I will post some photo's when they are complete.

The wings use cabinet screws from the inside, while the baffle uses 5/16 threaded bolts with inserts.

Finally making progress...

I wish I could do that! At least it's almost glue up time. A day to paint and dry... moving...installing driver... can't wait!

DJ,
I am still thinking of building myself a pair here in a few months.

My idea at this time is to perhaps use a different driver, well, just because.

Maybe a coaxial driver because they seem to have my attention right now.

I need something to keep myself occupied!

The DFH are coming along. They are made of MFD with a (for now) plywood baffle. The MDF was cut on a new Bessie CNC machine and assembled by me and my cabinet builder. The first unit took awhile to figure out and the second unit was glued up in 3 hours. Steve's prints are very good but I will send him some suggestions to modify the prints for easier assembly.  The speaker baffle could be better if made with 1" material because the P-10 driver is pretty heavy. TIP: When installing the threaded inserts in the baffle, use a drill press to make sure they go in straight.  I think I will make another set with round stone baffles.

So, today is the final paint. We will not use the "SkufX" as planned but a fine oil base matte black.

These cabinets will be very good I think because we just tap the "tree stump pillow"  inside and hear a lovely thump emanating from the horn opening. These boxes are wooden amplifiers!
I encourage people dreaming of building these to do it, it's very satisfying and I'm almost sad that the building process is complete. We will test them with a UFO in the shop. My shop people are not permitted to listen to musical instruments, only acapella gospel singing, so I have to find some of that type of music. All in all, I'm very excited in this exercise in obsession.  

Congratulations!  They look well executed.

Steve

Steve, Thank you for noticing. I will check.
If missing, I hop I can get that "I" piece in there!

Yes, I pray it will fit without too much fuss.

Excellent work DJFreon. Nice shop too. Don't let Steve's adventures get under your skin! It just his foresight in design that leads to improvements....hopefully anyways.

To be honest, didn’t think I would be able to complete this project on my own in my small garage, but finally, I am at finish line.
Body – MDF veneered in American walnut
Baffle – Solid American walnut timber

I now have speaker envy!

Alex

Welcome to the Decware Forum. Several posters are speaker builders, but I am not one of them, unfortunately 😄. With that said I can offer some insights that might be helpful to your journey.

Let's start with your listening room of 14'x14'. Square rooms are notorious for wreaking havoc with a systems frequency response. The main problem with square rooms is that resonances across the width of the room will result in peaks & nulls at the same frequencies as resonances along the length of the room. For example: subwoofers are placed to get rid of a null at 35Hz but that null still shows up in measurements. That's because the placement might have fixed the width mode at 35Hz but it didn't fix the length mode at that same frequency. I suggest you look into this issue carefully and check out reputable companies that can help you with treatment options. Whichever way you go with your speaker build selection, you'll likely benefit from treating your room to address likely issues.

On the folded horn selection you might check with Steve to see whether a folded horn design with your amp & source equipment will work in your small room. FWIW I have a small listening room 13.5'x15.5' with a Decware ZMA amp and CSP3 preamp plus good source equipment. I have found the Caintuck Audio hardwood open baffle design with the Lii Audio F15 drivers produce the most accurate sound. I have treated my room with inexpensive hard foam diffuser panels to address the rear firing sound waves created by the open baffle design. Many forum members have built there own baffles (all sorts of materials - butcher block, plywood, etc.) with good results. Just some additional fodder for your consideration.

Best wishes for your musical journey.

HK

Alex,

I have built a speaker or two through the years and hopefully I can answer why MDF is recommended.

MDF machines better than ply, you won't have near as much problem with blow out of you cuts because MDF doesn't have grain.

Speaking of grain, you don't have the problem of lining up your grain while you cut it so that your finished piece isn't a patchwork of mismatched grain.

MDF is deader sounding, it absorbs vibrations better.
It also takes paint better and veneers better.

Also, and this is probably the biggest thing, MDF is cheaper.

Since this is your first project and you are planning on using a CNC, well you are going to make mistakes, might as well use cheap material.
I was in the CNC business for 46 years and I will guarantee mistakes will be made!

Lately I've been working more with solid wood, but that is more for the challenge.

Hopefully this helps you out.

Alex,

Here is a link to some good initial video tutorials from GIK:

https://www.gikacoustics.com/educational-videos/

HK