Stereo Integrity Dual HT18-v3 Build

I just finished my build of my stereo integrity HT18-v3's for my home so figured I'd share to give some inspiration to others.

Edited to fix picture rotations

Parts list:
4cu ft flat packs from Parts Express that are technically made for the ultimax.
SVS sound isolation feet
R-30 Fiberglass Insulation to line the interior walls
5lbs Acousti stuff from parts express (per box)
Deluxe 1/4-20 tnuts from parts express (epoxied in place)
Speaker gasket tape from parts express
Landau Foam from local dealer
White Vinyl from local dealer


Help from two friends in covering the box!



Flat Packs arrived
Attachment 16567



Laying out all of the pieces

Attachment 16517



Starting to glue them together

Attachment 16518

Getting SVS feet ready. They use the 1/4-20 tnuts as well.

Attachment 16568



More gluing

Attachment 16519

Sides being glued on
Attachment 16520


Silicone all of the seams to make sure no air leaks. Also siliconed the tnuts since the svs feet bolts were not long enough to go all the way through

Attachment 16569


Silicone Dry

Attachment 16570


I recessed some magnets in the front face on the backside in case I want to add magnetic grills in the future. I wish I would have purchased some stronger magnets for this. These are fairly weak and will require a much stronger magnet on the grill side to work properly.
Attachment 16554

Attachment 16571

Magnets epoxied in place.

Attachment 16555


I may have issues with excessive clamping...



Attachment 16573


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Attachment 16524


Boxes all glued together
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Breaking in and testing different things!

Test fitting the subs. Unfortunately the flat pack and the SI gasket do not work well together. So I won't be using it and instead just putting some of the gasket tape on the top and bottom of the sub to give it a more finished look. I could have routed out a little more of the box, but figured I would just end up messing more up and it would have required me to buy a new circle jig since I don't have one that goes up to 18.5".

Attachment 16528



Testing placement

Attachment 16574

I decided to follow the loudspeaker design cookbook and test out some different fill materials.

I tested the following:

No fill
Walmart Poly Fil 5lbs
Acousta stuf 5lbs
Sonic Barrier covering the side walls (not sticking because I didn't know if I wanted to use it or not)

All Results (colors go with individual results below)
Attachment 16536

Close up results (microphone placed 6" away in all tests from center of cone)

Attachment 16537

Sub No Fil

Attachment 16530

Sub Walmart Poly Fil

Attachment 16531

Acousta Stuff

Attachment 16532

Sonic Barrier
Attachment 16533


My results were following the Loudspeaker design cookbook very well
Attachment 16575

So I ended up doing a combination of fiberglass to line the walls and the the acousta stuff to fill in the rest of the area
Attachment 16535

I also wanted to see if anything "broke in" on these subs.

I measured them before, after 5 minutes, than after about 3 hours.

There was something that broke in within the 5 minutes, but no changes after that. You can see the impedance curve shifted to the left a little bit and it stayed this way from every measurement here on out. I bet if I would have tested after 30 seconds, 1 minute, etc, this would have been "broken in')

Attachment 16576

Finally the finishing of the box in the white vinyl

Thanks to Rick and Curt for their help in this process!


Landau Foam covering all sidesAttachment 16540
Attachment 16582Attachment 16581Attachment 16580

Vinyl Cut and my sewing marks to follow as I sewed
Attachment 16585

Sewing machine
Attachment 16583

Close up of my stitch pattern for the back. The top only has a single stitch shown to make it look cleaner.
Attachment 16584

Bottom getting stretched and stapled
Attachment 16587

One Done
Attachment 16591
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Close up of back of box
Attachment 16588
Feet on and some hide-it to hide the seem on the bottom
Attachment 16589
Both done and back in my garage
Attachment 16593Attachment 16592


Testing sub fit

Attachment 16595
final placement of one (the other is similar on the other side)

Attachment 16594

Now I just need to run some REW and SMAART to properly integrate the subs with the mains.

I have some buckeye amps that should be delivered right around Christmas coming. 6 channels of 502mp (for 5 main speakers and Voice of God speaker) and 4 channels of 252mp (for in ceiling speakers).

I also have some Philharmonic Audio BMR towers for Left and right and a BMR for center ordered and should be in sometime in January. For surround/VOG I have Philharmonic Mini Monitors that he offered for one round. I luckily got the last 2 pairs of those.

I fixed the rotation issues and the final picture issues. I don't know why they weren't showing up and just said attachment with no attachment.

Awesome build. Great job!!!

Those look awesome.
I'm actually surprised at the quality of the PE kit, those are well designed.

Good job following up not only with stuffing them, but following a perfect process to figure out which were worth a damn.
I learned that Acousta-Stuff is measurably superior to polyfill - after all these years just using polyfill because I could buy it local and "it's all just blown poly fibers anyway" [emoji38]
Are you sure you stuffed the same densities? That was interesting to see.

And AWESOME job actually doing legitimate upholstery. I've personally never used sewing (or owned a sewing machine that could do vinyl or leather), but I suppose that led me to become a master of stretching over the years [emoji38]

I seriously love the clean, professional look those have with the stitching around them.

What was it that made the sub gasket not work? Were the cutouts undersized for your sub? Not that you need a gasket with the vinyl, provided you have a good surface-to-surface mating, anyway.

Sent from my LM-G820 using Tapatalk

The gasket was just slightly too big and I didn’t feel like routing it out. It would have required a bigger circle jig and some finesse to mount a board perfectly in the center.
Attachment 16596

Quote:

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Originally Posted by geolemon

Those look awesome.


Good job following up not only with stuffing them, but following a perfect process to figure out which were worth a damn.
I learned that Acousta-Stuff is measurably superior to polyfill - after all these years just using polyfill because I could buy it local and "it's all just blown poly fibers anyway" [emoji38]
Are you sure you stuffed the same densities? That was interesting to see.

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I did not make sure about the densities but did make sure the acousta stuff was 5lbs worth and the poly fil was 5lbs worth. The acoustic foam (3/4" sonic barrier) was just enough to cover the outside walls, which was the recommendation for its use. The acoustic foam was loosely placed against the walls as I didn't know if I was going to use it or not. Sticking it on might change some things, but it isn't like I was pushing the sub super hard to cause that stuff to move a bunch. Dats sends a pretty small single and then measuring these outside of my garage with neighbors kept volumes relatively low.