Cabinet damping vs. no damping

birminghambass · #1 09-09-2012, 05:13 PM

I regularly gig two GK Neo 15s as a stack. Yesterday I opened one up to line the walls with acoustic foam. The GK cabs, while great, are known to not have any inside.
After lining the first cab I put it back together and listened to each side by side.

The lining made a HUGE difference. It cut the boom, made it sound MUCH more even through the lows and mids. It also seemed to cut the volume some.
I'm used to the non damping tone on these cabs so i'm not done deciding which one I like better yet. I'll A-B them at my gig next week and report back.

Buzz Grim · #2 09-09-2012, 10:22 PM

I'm interested to hear your post gig report.

JimmyM · #3 09-10-2012, 01:15 AM

I don't see how it could cut volume...only standing waves that may give the illusion of more volume. And really, tone is what matters. You can always turn up if you need to.

miiitch · #4 09-10-2012, 01:41 AM

how much did you put in?

i added 2 packs of damping material (meant for a box volume of 40L) to my 115 mbx .. already made a difference

Egbert89 · #5 09-10-2012, 01:47 AM

Also where did you put the lining? Only the backside, only the sides or pretty much everywhere?

birminghambass · #6 09-10-2012, 05:24 AM

Quote:

Originally Posted by JimmyM

I don't see how it could cut volume...only standing waves that may give the illusion of more volume. And really, tone is what matters. You can always turn up if you need to.

You're probably right about the "illusion" of more volume. It's a difference but not enough to effect the performance of the cab. Like you say, I can just turn up!

birminghambass · #7 09-10-2012, 05:25 AM

Quote:

Originally Posted by Egbert89

Also where did you put the lining? Only the backside, only the sides or pretty much everywhere?

I lined pretty much everything but the front baffle. Used mattress topper foam.

Jazz Ad · #8 09-10-2012, 05:28 AM

No damping in GK cabs? Really? Is there a good reason for this? I can't think of any.

Crater · #9 09-10-2012, 05:44 AM

Quote:

Originally Posted by Jazz Ad

No damping in GK cabs? Really? Is there a good reason for this? I can't think of any.

Well, it saves time and material in the manufacturing, and we all know that time = money. There was at least one thread on this subject earlier, various speaker design experts agreed that all cabs should be lined to eliminate standing waves, resonances, ect. Bob Gallien chimed in and said his cabs are designed without damping and that they sound fine without it. The marketplace seems to agree.

kringle77 · #10 09-10-2012, 05:58 AM

I am a big fan of mattress topper. 1 layer does the trick, it's cheap, easy to find and clean to work with. I have made several cabs sound much better by replacing the thin layer of poly they had with this foam.

Egbert89 · #11 09-10-2012, 07:07 AM

I used that eggshell formed sound damping foam for a cabinet I build my self. Works great together with some bass ports (calculated the size and lengt of the port with winISD)

staindbass · #12 09-10-2012, 09:01 AM

the lining soaks up some of the sound that bounces off the interior walls and reflects back out through the paper cone making is seem a pinch quieter.

JimmyM · #13 09-10-2012, 11:11 AM

Quote:

Originally Posted by Crater

Well, it saves time and material in the manufacturing, and we all know that time = money. There was at least one thread on this subject earlier, various speaker design experts agreed that all cabs should be lined to eliminate standing waves, resonances, ect. Bob Gallien chimed in and said his cabs are designed without damping and that they sound fine without it. The marketplace seems to agree.

Do they? Or do they just expect them to be of high quality because they're GK and the people who buy them don't know any better because manufacturers do a piss poor job of educating us?

beans-on-toast · #14 09-10-2012, 11:39 AM

Some companies use a spray on damping material like Acoust-X. More expensive than a lot of classic type damping materials. Same company that sells duratex.

If you look in a cab and don't see batting of some sort, it still might have damping if there is a coating on the inside surfaces.

will33 · #15 09-10-2012, 11:48 AM

Quote:

Originally Posted by JimmyM

Do they? Or do they just expect them to be of high quality because they're GK and the people who buy them don't know any better because manufacturers do a piss poor job of educating us?

Showing some solidarity here against the marketeers dis-info campaign.

Yeah, I like my GK stuff but that does not mean they are beyond criticism. In that first MB cab bracing/damping thread, rag himself stated that they don't need it, they are designed that way, yet, now the newer production runs of the same cabs are being built with what looks to be a fair amount of bracing inside. This didn't happen until after several complaints from people's MB cabs and especially combos rattling/vibrating apart after a few months and a couple people here taking theirs apart to find nothing inside. Ya can't have it both ways. Maybe someday they'll put $3 worth of lining in there.

JonnyAngle · #16 09-10-2012, 11:54 AM

As a manufacturing estimator/ designer, I can't see that adding the batting or adding the labor to put it in would have that big of a difference on the price of the cabs on a large scale. Like Jimmy said, it's probably like $3.

$3 to add batting/ $400 cab = .0075% difference in price per cab. That's not going to put GK out of business.

JimmyM · #17 09-10-2012, 11:57 AM

Actually, Will said that

And honestly, it's probably $3 worth of batting ar our price. Bob Gallien has the buying power to buy it by the ton, and it would likely cost him pennies per cab.

will33 · #18 09-10-2012, 12:06 PM

Ya, it was just a guesstimate on the wholesale/retail price thing. Whatever it is, it's cheap and only involves about 5 minutes worth of labor during the build process.

As an example, if you use the mattress foam, you can get a piece for about $10 retail that will do one big cab or 2 small ones and have some left over. The stuff probably costs pennies to make. Wholesale/bulk will be somewhere in between there.

carl h. · #19 09-10-2012, 12:16 PM

First off I agree the lining should be done, but it isn't just the cost of the material itself. It has to be purchased - billing has do be taken care of. It has to be stored somewhere dry and away from rodents and insects. It takes time to cut it to fit and someone has to do it. You need something to cut with, and that will need to be purchased and maintained. Also if it is going to be done it should be done properly - some R&D time and money involved here too.

AstroSonic · #20 09-10-2012, 12:19 PM

Based on the image, it looks like you have some material in the vent. If that is the case you should try removing the material from the vent, and away from the vent opening inside the cab. Material in those places will strongly weaken the effectiveness of the cab/vent resonance. Just put a 1-2 inch layer of the acoustic insulation on the back, bottom and one side, being careful to keep it away from the vent. This worked well on my MB-115. I found that about 1/3 pound of 'Accoustastuff' was optimum. Much more than that and it flattened the tone. Your cab (and ears) may be different. Just try a few different amounts and pick the one that sounds the best. These cabs sound great stock, but just a little insulation does seem to improve the tone.

Bob