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-   -   Have you ever seen a pair of tops/ speakers cabs without damping material inside? (http://www.wavemusic.com/community/showthread.php?t=13931)

Reticuli 10-03-2013 12:57 PM

Have you ever seen a pair of tops/ speakers cabs without damping material inside?
 
I have a new pair of Peavey Impulse 12Ds. My first used pair (of which I have one still) had it inside. Black gauzy stuff that looks like black painted BAF. These new ones don't. I very briefly had another newish pair of them from Guitar Center that also did not have any. Long story short: one of those sounded like an incoming artillery barrage (thankfully I was behind the speaker when I powered it up for the first time), the other had a bent knob on the back. GC quickly swapped them for me. Is it possibly some computer-designed cab that doesn't need it? I noticed the first used pair's gauze inside had a slightly chemical smell that didn't bother me, which obviously was pumping out with the bass. I'm wondering if Peavey just started yanking it out due to complaints about the smell. The pair GC replaced (artillery, bent knob) literally looked like it had been installed and then yanked out. There were glue and gauze remnants inside.

Simple question...

Is there any justifiable reason not to have damping material inside?

Estacy 10-03-2013 01:46 PM

profit.


Thats it. profit.

Reticuli 10-03-2013 02:11 PM

Yeah, but wouldn't ripping the gauze out on the second pair I had (not sure about the third pair sitting here... they look clean inside) add another production step or ridiculous manpower usage at Peavey's portside warehouse? I could see remnants of the gauze and glue in the second pair.

Someone on another forum mentioned damping material in a ported top design being partly to reduce woofer distortion. These scorpion woofers are 4 conductor servo coil feedback controlled, though. Maybe that's why?

Anyway, with the Peavey warranty and the GC warranty, I have three different options for having damping material installed for me by Peavey, GC, or a local repair facility. Do you think it's worth it since it would be free of charge?

Reticuli 10-03-2013 05:02 PM

Wow, I went back and double checked the insides thoroughly with a flashlight. There is some slight evidence of the gauze having been in this pair, too. It was torn out. Maybe it’s the paint they used on the BAF that compelled Peavey to remove it. They are made in China. If it’s something toxic, though, I’d like to know so I can rip it out of the original cab. There is no reason to remove the gauze in order to get to the woofers, replace them, or do anything like that. Back tubs slide out nicely. Front woofer grill and woofer comes off. Cables all disconnect at halfway points with little white plastic couplers. Removing it is an extra step that adds cost. It doesn't make sense if it's just bean counters.

pbellsound 10-03-2013 09:55 PM

There's a kinda new speaker cabinet blanket on the market, I don't know it's name.

It's a very fluffy cottony material that must be in a gauze like net. Without it, the fluff blows all over. It "absorbs" better than the usual stuff.

Better designed cabinets don't "need" that much insulation in them. It's function is to "trick" the woofer into thinking the cabinet has a larger volume than it does. This is all done through the thermal expansion of air under pressure and the thermal absorption abilities of insulating materials.

Reticuli 10-03-2013 10:52 PM

Quote:

Originally Posted by pbellsound
There's a kinda new speaker cabinet blanket on the market, I don't know it's name.

It's a very fluffy cottony material that must be in a gauze like net. Without it, the fluff blows all over. It "absorbs" better than the usual stuff.

Better designed cabinets don't "need" that much insulation in them. It's function is to "trick" the woofer into thinking the cabinet has a larger volume than it does. This is all done through the thermal expansion of air under pressure and the thermal absorption abilities of insulating materials.


Are you saying that's what I should use, or are you saying that's what Peavey might have used and they changed their mind about needing to spoof the cab volume and thus that reducing the woofer distortion is possibly not a concern?

DSA.audio 10-04-2013 01:13 PM

old hammond " power cabinets" (40s vintage originations) for their electric organs had no stuffing....
but they had good volume....

DSA.audio 10-04-2013 01:20 PM

I do not believe cost cutting was foremost on their minds btw...
not in the early years.... their organs = bulletproof...

now, each unit is unique... which can be a source of frustration, if that's not what you expect...

pbellsound 10-04-2013 08:30 PM

I suppose the most correct answer would be to call Peavey and ask them.

They might just send you the stuff for free.

Reticuli 10-05-2013 05:48 AM

Quote:

Originally Posted by pbellsound
I suppose the most correct answer would be to call Peavey and ask them.

They might just send you the stuff for free.


Peavey said they could not tell me the reason why it was removed from the design. And they do not have the particular damping material used by the OEM on the earlier units in their own inventory. If I wanted to send them to their HQ, that would be at my expense. They are willing to pay a local service center to put damping material in, but I'm hesitant to use it after a prior experience I had. I do also have a 2yr pro warranty with Guitar Center on the cabs. Do you think it is possible from an acoustic standpoint that gauze damping is either unnecessary or even a bad idea?

Reticuli 10-15-2013 05:03 PM

Shit, now they said they won't cover it.

rs_ 10-19-2013 08:29 PM

Many vintage Klipsch speakers, for example, don't have internal damping of any kind. They were designed not to need it. I've got (6x) Heresy Industrials in the shop I'm writing from, and none of them have any damping at all. (Klipschorns were used in The Loft sound system if I remember right.)

There is an apocryphal story of someone being kicked out of Paul Klipsch's house in Arkansas because they asked if internal damping might improve the sound. As the story goes, he was outraged that they would think he hadn't considered something like that in his designs.

Furthermore, I'm about to build some cabs for some vintage full-range horns (Altec 511), but those will actually work fine mounted to a board, with maybe a little modelling clay or similar around the throat.

So, it is quite possible that it's not there by design. If you really get stuck, ask for Marty McCann at Peavey. He can help you. They're good people in my experience, despite moving their manufacturing operations from Meridian, MS to China.

rs

Reticuli 10-23-2013 03:46 PM

Quote:

Originally Posted by rs_
Many vintage Klipsch speakers, for example, don't have internal damping of any kind. They were designed not to need it. I've got (6x) Heresy Industrials in the shop I'm writing from, and none of them have any damping at all. (Klipschorns were used in The Loft sound system if I remember right.)

There is an apocryphal story of someone being kicked out of Paul Klipsch's house in Arkansas because they asked if internal damping might improve the sound. As the story goes, he was outraged that they would think he hadn't considered something like that in his designs.

Furthermore, I'm about to build some cabs for some vintage full-range horns (Altec 511), but those will actually work fine mounted to a board, with maybe a little modelling clay or similar around the throat.

So, it is quite possible that it's not there by design. If you really get stuck, ask for Marty McCann at Peavey. He can help you. They're good people in my experience, despite moving their manufacturing operations from Meridian, MS to China.

rs


It was in there originally, but it appears to have been torn out on the new ones. I'm wondering if the black paint on the BAF stuff might be toxic. If that's the case, I'd like Peavey's engineers to tell their reps that, instead of the lack of communications. If it's bad, I'll rip it out of the older one.

rs_ 10-31-2013 01:01 PM

Yeah, I just wonder if the design didn't change or evolve not to need it anymore.

It is definitely possible to have a good conversation with somebody at Peavey, but I'd frame the discussion in terms of acoustics and not in terms of environmental pollutants since I'd think that would automatically put whoever answers the phone in "C.Y.A." mode.

rs


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