[mikeeastman]

The driver died in my DIY sub, I ordered a new driver  but it needs 1.25 cu" and my box is 1.5 cu", can I us some high density Styrofoam covered with No-Rez to fill the space or would it be better to us MDF or the same stone I lined the box with ( see post of sub build http://www.audiocircle.com/index.php?topic=119671.0 )? What would be the down side to not reducing the volume of the box for the new driver?

[TF1216]

I had success shrinking a box with high density (pink) insulation purchased from Home Depot. Cut to size and glue into the box.

With the T/S parameters for your new driver one can determine how the two box sizes will compare. I don't have a suggestion for the best tool to use but there are many available for free.

[charmerci]

How does a big, beefy sub driver like that fail?


Inquiring minds want to know!

[S Clark]

I had success shrinking a box with high density (pink) insulation purchased from Home Depot. Cut to size and glue into the box.

With the T/S parameters for your new driver one can determine how the two box sizes will compare. I don't have a suggestion for the best tool to use but there are many available for free.

I know that it is counterintuitive, but adding fiberglass insulation effectively makes the box bigger.  It converts sound pressure to heat as the fibers are flexed.  Instead, add a block of Styrofoam equal to the volume of reduction that you need.

[TF1216]

I know that it is counterintuitive, but adding fiberglass insulation effectively makes the box bigger.  It converts sound pressure to heat as the fibers are flexed.  Instead, add a block of Styrofoam equal to the volume of reduction that you need.

I should have worded my approach better. This material was very much like styrofoam and stiff as a board of plywood.

[S Clark]

The key is that it must be "closed cell"--- meaning that air cannot penetrate it.  Closed cell foam (the type you can't blow through) reduces a box size, open cell increases it. That ought to clear it up.

[poseidonsvoice]

Mike,

If it's a sealed sub, and your new driver recommends a smaller box, why are you concerned? The larger box (1.5 cubic feet) will provide a tighter bass, lower Qtc, and deeper bass at the expense of lower spl for your deepest frequencies, with the new driver If it's a ported design, then you must model to see what will happen.

Model it anyway even if it is sealed , you'll see what I mean. I'm not even sure if it will make that much difference honestly.

Best ,
Anand.

[mikeeastman]

Thanks for the info. It is sealed and in my bed room so sounds like it won't be a problem just using box as is. Don't how I blow the drive. The diaphragm just started to buzz, can't find anything loose and the coils seam fine? and I only have about 60 hrs on driver.

   Mike

[JohnR]

You're certain it's the driver and not the amp?

[S Clark]

You're certain it's the driver and not the amp?

Good call.  The amp is the more likely suspect.

[mikeeastman]

I tried a different amp and driver still buzzed and I tried a different speaker on the amp and no buzz?

[JohnR]

Good you checked  What driver is it?

[mikeeastman]

I retested and you were right it's the amp    thanks for your post or I won't have retested the driver. IT is an old ADS duel voice coil that I had in my storage closet for years, but never used.