SVT-210AV - polyfil

[Bob Wachunas]

Hello TB'ers

I have an SVT 210AV cabinet, I've been playing gigs with it for about a year, and I like the classic Ampeg tone, but one thing I notice with this cabinet is that it always requires some EQ tweaking because it's pretty boomy in the low-midrange. The cabinet is a bit hollow/woody sounding to my ear.

To mitigate this I stuffed the cabinet with polyfil and overall the results sound very good to me, but perhaps I have overdone it. The sound is much less boomy and doesn't seem to need any EQ at all. The resonant frequency seems much lower!

On the down side, the cabinet is heavier, and acoustically seems less efficient and less responsive, a little thuddy on the low B string.

There is plenty of room behind the drivers so nothing is touching the cones. How much is too much polyfil? Should it be loose or fairly dense. Symmetrical or leave some off one side?

I am wondering whether any others have had experience stuffing the SVT-210AV and how dense should I stuff it?

Also, can stuffing this cabinet with polyfil cause any damage to those custom Eminence drivers?

I know, I should experiment on my own and find what works best. And, I have done that, and this is not the first cabinet I have stuffed. But I wanted to get other TBers perspectives on it. I am especially curious whether any others have seen the same improvement I have seen stuffing the SVT-210AV. And, can over-stuffing damage the drivers?

Thanks in advance,
Bob W in Santa Rosa, CA

 

[AstroSonic]

While I haven't installed acoustic damping material in the SVT210av, I have done so in many other bass cabs, PA speakers and hifi speakers. The result you describe is likely the result of too much polyfill. This will not harm the drivers provided that the polyfill does not press against the speaker cones.

A method that works for me is to listen to the cab sans fill and pick up on any peaking, hollowness, etc. Then start by just lining the interior with around an inch of damping material. If the effect of the acoustic damping has gone too far, I drop back to lining only two adjacent sides and half the back. Listen again. OTOH, if th complete lining was insufficient, I tease out some fill and losely fill the cab. I almost never 'stuff' a cab.

 

[Bob Wachunas]

Thanks for the insight AstroSonic. Your method shows a lot of restraint... and patience. At 53 years young, these are lessons I still need to learn it seems. I will go back and give that a try.

PS. my avatar photo was taken in New Mexico. (you can tell by the lighting)

 

[JimmyM]

Wow, what kind of amp and bass are you using? If anything, I have to add a little bass response to mine. But since we're not all the same or looking for the same thing, hope you get the stuffing worked out!

 

[Bob Wachunas]

Hey JimmyM,

I have a Trace Elliot ELF for power and the bass is a 5-string Ibanez SDGR. Personally I don't like too much low-end thump and I no longer enjoy lugging around rigs that don't fit in my car. (The two reasons I gave up the SVT-810 years ago.)