Sealed subs, EQs and replacement amps

[Chane M&C]

In another thread, Mr. Chase posted the following:

All subwoofers from commercial sources have a built in eq curve, both sealed and ported.

The "ideal" curve for making a sealed subwoofer work in room is similar used by the Maestro from ACI and later the Submersive from MS II.

This is also nothing new - the same EQ curve has been used by sealed sub designers for decades.

The single 10 inch we are designing is going to be something pretty special, as it will have all the SQ Jack and Ray heard here last month, in a very compact package.

I love this 10 inch driver's SQ. I know, some guys will say there is no such thing. Those guys love making statements on SQ by looking at a spec sheet.

This 10 needs to be heard to be appreciated.

I own a really old M&K sub (circa 1989). It's amp has since died but the 12" driver is still in good shape. Well, actually, M&K replaced that driver several years ago so I think it still works. Anyway, as M&K is no longer in business, it seems that the only option to bring this old sub back into service is to buy some aftermarket amp for it. However, I always suspected that M&K (and other subs manufacturers) added some hard wired eq'ing to shape the response curve for the sub. And I suspect that this eq'ing is not replicated in commonly available sub amps.

Any advice on how I should go about this amp replacement? Should I just pick an amp put and buy an eq or is there a better way?

[Jason]

I would suggest pm'ing Craig and asking him....he might know of an off the shelf amp that would have a reasonably close curve built in.

Otherwise, I'd suggest looking into an outboard eq. There will be other advantages to that route, as you will be able to adjust for the room, which has far more influence than some small eq meant to make a sub perform better for ground plane.

[dvenardos]

I have asked this question before, but not gotten much of a response. It shouldn't matter if you do the eq in the amp or external. I would get an amp, measure the freq response and go from there. Or, if you can get the specs on the driver, you could model it and see what it looks like in your enclosure.

[Sandbagger]

In another thread, Mr. Chase posted the following:



I own a really old M&K sub (circa 1989). It's amp has since died but the 12" driver is still in good shape. Well, actually, M&K replaced that driver several years ago so I think it still works. Anyway, as M&K is no longer in business, it seems that the only option to bring this old sub back into service is to buy some aftermarket amp for it. However, I always suspected that M&K (and other subs manufacturers) added some hard wired eq'ing to shape the response curve for the sub. And I suspect that this eq'ing is not replicated in commonly available sub amps.

Any advice on how I should go about this amp replacement? Should I just pick an amp put and buy an eq or is there a better way?

I donat know the model of your sub, but a friend had a M&K die on him a while back, before they went under. From what I remember it was just 2 big caps in the power supply. pretty simple to replace, and based on the age of your sub, its a very big possibility that is all it is. I would open it up and see if any of the caps are leaking or bulging or even exploded and just leads sticking out of the board.

[lngbruno]

adodo,

Like others have stated, you will need to experiment and test the results. You could try a plate amp from Parts Express, Apex or Rythmik and see how they work. I have seen two applications of where an alternate plate amp was used with very great success.

Good luck,
Lou

[NekoAudio]

If you're going to use an outboard EQ (which you should anyway) then you don't need to try and find an amp that will accomplish the same. The only exception being if a limiter was placed on your sub to prevent damage. In which case you may need an EQ with a shelf filter to cut frequencies below some point.