Behringer Feedback Destroyer....anyone use one?

Ron-P

I've got the SonoSub in its final resting place and have been working on getting it calibrated. When running the LFE sweep from AVIA I have found a 10db peek between 40-45Hz. I've read that the BFD will allow me to go in and flatten out the response in this range. Has anyone or does anyone use one of these? If so, does it work.


Peace Out~:D

RuSsMaN

Ron, I'm not familar with the BFD, but a couple questions.

What are you using to calibrate? If its the rat shack, I've heard they aren't REAL accurate, esp below 80Hz. Have you put the sub smack dab in the middle of the room and gotten similar results? Does the mcm amp have a 'bass boost' at 35Hz or so?

Also, I can't remember if you went sealed, or ported, if ported, how did you calculate your port length and diameter?

Cheers,
Russ

Ron-P

Russ,

I am using the rat shack SPL meter, do you know of something better?

I have put the sub in the middle of the room and have the same results. I also put it on the other side of the room and the peeks got worse.

The plate amp does have the bass boost on it. Is there a way to remove it?

It is a sealed tube. 177L or 6.2cf.


Peace Out~:D

RuSsMaN

I use a rat shack also, and I don't know of anything better, thats affordable (cheaper than a half octave Eq anyway- which would cure it in a heartbeat).

There should be a way to bypass it, I know I have seen threads on a couple PE amps, and disabling the boost feature. Does mcm have a forum? I think it is simply bypassing a single cap in one of the amps circuits, basic soldering. I'll look around.....

Good call on the sealed design, that will rule out the port length/size nightmare. And hey, could partially be due to the room also, might need some corner basstraps with your new monster.....

Cheers,
Russ

hoosier21

There is a compensation chart for the RS SPL Meter. I will post the link here when I find it.

Check with MCM, they should have instruction on bypassing the bass boost .

vtec11

damn !!

are you serious Russman. i just bought the radio shack meter like an hour ago.

is the digital one any better ?? 33-2055 i think is the model # for the digital one.

because i think the 33-2050 is the one polk used to give out with the SRT.

RuSsMaN

Just what I've heard, thats all. Not saying its a bad meter.

Kind of like bathroom or kitchen scales. For the most part, they are pretty accurate, but they have the little disclaimer 'not legal for trade purposes' or some such.....

I still think its worth having....lets see what Russ post's regarding this chart....

Cheers,
Russ

Ron-P

Good call on the sealed design, that will rule out the port length/size nightmare.

Exactly why I did not go ported for my first D.I.Y. sub. I may, down the road, build a ported sub.

If you find that chart, that would be great. It will help in finding out my true db peeks.

Thanks for the help guys.


Peace Out~:D

Ron-P

Found the chart. http://www.svsubwoofers.com/faq_rscomp.htm


Peace out~:D

madmax

Ron,
I'm still an amatuer at this sub design stuff but it sounds like the room gain is taking place before the sub is dropping off. (not by much if you have a sharp peak around 40-45 hz). With that being the case you could tune it by removing a little area from the tube. People use phone books and such to do that. Once you get it right you can cut the tube or just leave the stuff in there. Much better solution than electronically eliminating it.
Audio Control makes a nice sub eq/setup component if you want to do it electronically
madmax

hoosier21

Yes there is the chart, not the one I have seen but it look shte same, it does not help your cause you are adding 2.5db at 40hz:(

goingganzo

i have the anilog rat shack db meter

Ron-P

Very interesting Max. I'd not heard of that. I may have to slip in a phone book or two and see what happens. Others I have talked to say as you do. Try and aviod doing it electronically. I will try the phone book theory this weekend and see what happens.


Peace Out~:D