SDA1B Dampening question

gilberca

After updating my SDA1B crossovers, I've noticed an increased amount of bass response to the point where the cabinets seem to be adding resonance to the sound. The poly batting was reinstalled behind the woofers and upwards in the cabinets. No fill is behind the PR.
Would adding 1 1/4" Sound Barrier behind the woofers improve dampening in the cabinets?
I'm looking at this product: https://www.parts-express.com/sonic-barrier-1-1-4-3-layer-acoustic-sound-damping-material-with-psa-18-x-24--260-535
I have not Dynamatted the speakers as yet but they are all Hurricane Nutted and have 1/16" new gaskets so the cabinet itself is reasonably air tight.

Thanks in advance
CalG

RandyCroissant

Hi CalG and welcome to the forum, I used the sonic barrier you mentioned in my 2b build. Very happy with the results and recommend it. Using this product in 3" wide strips directly behind each Mid Woofer will help minimize the back wave reflection and help clear up the mid and bass performance, be careful though if you use to much it will diminish the bass.
Randy

audioluvr

Did you reseal all your interior seams? If not, that could be a source. Also make sure you dynomat the driver and PR baskets and add the strips of sonic barrier behind the drivers. All these make for a very nice improvement.

F1nut

Do the air leak push test before doing anything else.

The original gaskets were literally paper thin. Thicker gaskets are not required and may cause air leaks.

gilberca

F1nut: pushing in on the PR yields about 3 secs before the woofers retract to rest positions. The foam tape I used compressed down to perhaps the thickness of a business card.
Randy and Audioluvr: I inspected the interior seams and they were still well-sealed when I was redoing the crossovers. I also hotmelt glued the rear binding post mounts to make sure that would not leak.
Since the consensus is dynamat and sonic barrier, I'll get both before reopening the cabinets.

Thanks for the help
Calg

F1nut

Ok, seems like you don't have an air leak. Dynamat Xtreme is to help stop any basket ringing. It does not have anything to do with bass response. Sonic Barrier helps clean up the mid-range, but I doubt it will help resolve your issue.

What caps did you use and were they exact values? What are your speakers sitting on? Are your speakers spiked? How close are they to the back wall?

gilberca

F1: Here's what I used in the Xover build:
HF:
2x .0.50 Ohm Vishay Mills MRA-5 to replace the RDE090 Safety bypasses
6x 2.7 Ohm Vishay Mills MRA-5
2x 2.0 Ohm Vishay Mills MRA-5
2x Gen I Sonicap 4.4 uF 200VDC with Precision Matching
2x Gen I Sonicap 12 uF 200VDC with Precision Matching

LF:
2x Solen Capacitor 180.0uF 400Vdc PB Series (original value was 184uf)
4x Solen Capacitor 33.0uF 400Vdc PB Series (original value was 34uf)
2x ESQ55-16-10000 10.0mH 16ga ESQ - Super Q Coil Dewound to 9.6mh

The speaker cabinets are supported on 1" diameter felt lined feet that I can height adjust.
They sit on hardwood flooring and are 7" from the back walls and at least 4' from any corners. The room is approximately 24'x16' with a sloped cedar ceiling that runs from 12' to 8' over the room width. Speakers are about 10' apart and I'm listening to them about 18' back.

After the xover update, bass is much more prominent; in some music its better defined, but in other music, it's too emphasized. I'd even go as far as saying its muddied. I can turn-down the LF on the preamp but prefer to keep all the dials set to neutral.

RobbyKY

Take a close look at the Super Q's.

The two builds I've done with the Q's have more defined bass for certain.

I have:
1.2tl Super Q Sonic Barrier
1.2tl Solen Black Hole 5
3.1tl Super Q Black Hole 5
3.1tl Solen Black Hole 5
2B tl Jansen Sonic Barrier-->(I think, been a while)

The 1.2tl with the Q has way more defined bass then the Solen-based build but was not sure if the BH5 is just that much better than the Sonic Barrier or it's really the "Q".

The 3.1tl with the Q (my latest project) is still way more defined in the bass department over the Solen-based build and both are rocking Black Hole 5.

My son uses the Q-based speakers since that's just his music taste. In fact I just bought him a 505 sub to help him shake the windows but immediately regretted that move.

My personal taste and go-to set-up is the 1.2tl with the Solen in the dimensional circuit and Black Hole 5 dampening.

Check the DCR on the Super Q's. The last two I bought (from PE) ran the same inductance but were way different in DCR. After unwinding to adjust the inductance, the DCR's were even further off. I pulled, sat on a shelf and ordered two new Super Q's directly from Erse. These measured the same DCR and remained matched after adjusting the inductance.

ThomasD

Not to hijack the thread but since the 'Sonic Barrier' dampening material (or is it damping?) has been mentioned by the OP & compared by @RobbyKY to BH5, is there any other comments about the difference between it and BH5? It's certainly less expensive. Asking because I was literally going to order the BH5 this morning from Speaker City (which seems to be the only distributor I can find) to install in my SDA 2a's, when I found this thread. Want to get an order in soon but don't want to regret not using the 'tried & true' unless the alternative is actually less expensive & equally effective. Thanks
P.S. @RobbyKY Impressive SDA's & in pairs. I can't find singles up here!

RobbyKY

Check out Sonic Craft for the Black Hole 5

http://www.soniccraft.com/product_info.php/blackhole-p-50

The only reason I went with the Sonic Barrier in the past was the inability to get my hands on the BH5.

The one source that did have BH5 available then was looked upon poorly by @F1nut as perhaps not the same quality as what had been on the market in the past.

When I started the latest 3.1 built, I just happened to check Sonic Craft while ordering my Cardas binding post and there it was again. Seems to match the tiny left-over sample of BH5 I had bought years ago. Highly recommend dropping the $75 on a sheet.

VR3

One of the best dampening products on the market is No Rez by GR Research, IMO.

Sonic barrier is less expensive and dosnt work quite as well. The best SB that I can recall is the 3/4 I believe, has 3 layers.

http://gr-research.com/norez24x27sheet.aspx

codycatalist

VR3 wrote: »

One of the best dampening products on the market is No Rez by GR Research, IMO.

Sonic barrier is less expensive and dosnt work quite as well. The best SB that I can recall is the 3/4 I believe, has 3 layers.

http://gr-research.com/norez24x27sheet.aspx

Not too pricey either when comparing to BH5.

VR3

Nope and its awesome.

audioluvr

BH5 was on backorder for quite a while so others (including me) were using the 1 1/4" Sonic Barrier. I never was able to do a comparison but the Sonic Barrier DOES work and made my SDA 1C's sound fantastic.

gilberca

Regardless of the damping material used, am I correct with installing 2 3-4inch wide strips behind the woofers? I'm assuming the length would be about 12 inches.

Thanks
Calg

RandyCroissant

Yes! I used 3" wide strips, 4" might be a little better or worse.

ddog

Would you guys recommend doing tthis to other Polk speakers, like say 3.1's?
Or only just certain moldels..?

Once again, I'm very new to all these speaker mods...

ddog

Oops...never mind I see that was a dumb question...
I haven't had my coffee yet this morning...lol

RandyCroissant

Howdy ddog, I believe most older polks should benefit from this mod.

ddog

RandyCroissant wrote: »

Howdy ddog, I believe most older polks should benefit from this mod.

Okay thanks Randy...
I started reading this thread the other day.. great thread by the way...
So this morning I zipped down to the bottom to read the last post, then asked my already awesome question...lol

I have hurricane nuts coming today but I think I may wait to install them till after the "sonic barrier" material arrives.
I'm going to order two sheets of what @VR3 suggested.

Building bass traps today...
I love the wonderful world of AV!

ThomasD

Sheeeesh..... $86 cost of 2 sheets & over $56 USPS ground shipping. Need to cut those into smaller sheet size.

ddog

No...it was $127... delivered.
It is kinda bogus how they charge twice for shipping...but.
Only was to do this once. Leftovers will be applied to other speakers.

Thanks

ThomasD

ddog wrote: »

No...it was $127... delivered.
It is kinda bogus how they charge twice for shipping...but.
Only was to do this once. Leftovers will be applied to other speakers.

Thanks

Sorry, should have clarified. That's what my cost is to get 2 sheets of it shipped here.

ddog

Either way...it is kinda steep..
Still better priced the bh5 link earlier in this thread.

F1nut

BH5 is the standard.

gilberca

Update:
I ordered and installed the 1/1/4" Sonic Barrier from Parts Express.
The install went smoothly. I cut the barrier into 3.5" strips and trimmed them to 20" length. 2 strips per cabinet were installed behind the woofers and extended into the upper portion of the cabinet. I then reinstalled the polyfill, making sure it stayed behind the woofers with no fill or dampening behind the passive radiator.

I've had a chance to test out the modification and am impressed with how the bass tightened up. It is no longer muddied and the cabinets no longer resonate/vibrate as they did prior to the Sonic Barrier install.

Thanks for all the advice.
Calling this one done for now.....

audioluvr

Good Job!