Reusing Old Sub Boxes?

[hawkson]

Hi,
What are the downsides to Reusing an old subwoofer box from the 90's and 2000's?

I have access to PROFESSIONAL sub boxes(not wood). My idea is to take 15" drivers and put them in the used boxes, wire them and amp them externally.

What are the downsides? Is there something I should be aware of? The alternative is building a specifically designed sub box out of wood, which takes more time and money, but it can be tuned and designed for the specific driver.

I will be making 2 and then 4 15" subs.

 

[killa12222]

As long as the internal volume is big/small enough for the driver, I guess it should be fine.

 

[hawkson]

Can someone explain how to "Tune the box" to 20Hz or 25Hz?

What do you mean by small enough?

 

[Top Shelf]

What kind (round, oval,rectangular) of ports are in the "not wood" boxes now? Can they be extended if need be to retune to the new 15" speakers T/S specs? What size are the boxes? What brand/model are the 15's and do you have measured or manufacturer T/S specs?

 

[weltersys]

Can someone explain how to "Tune the box" to 20Hz or 25Hz?

What do you mean by small enough?

You can make a box tuning (Fb) of 20 or 25 Hz or any frequency you want using the JBL nomograph below.

Any port shape may be used, though keeping the port close to circular or square will result in results closer to the nomograph predictions.

After installing the ports, it is always a good idea to check Fb using a swept sine wave, the cone movement will be at minimum at Fb. Much easier to cut ports down than to make them longer, start a little long and cut them down till Fb is where you want it.

Lower Fb in the same size box comes with a reduction in SPL level, Hoffman's Iron Law.

Art Welter

 

[johnr66]

Download a free box modeling software and learn to use it, like WinISD. You can enter the speaker parameters and find a driver that fits the box volume you have and add or mod the ports if present.

 

[epa]

if you measure internal volume ,and port dimensions,you propable could find a driver 'to fit your requirements.