Would it be worth upgrading the woofers in my subs?

[wuzzzer]

Several years ago I picked up a pair of Peavey THX subwoofers that had been used in a movie theater.  I paid $80 for them.  I know Peavey is Peavey but they actually work very well, especially for music.  I am powering them with a Crown Xti1000 amp.

I had to move them tonight since we're having our carpets cleaned tomorrow and as I was doing that the thought ran through my head about getting different woofers for them.  Right now they are stock Peavey 15" Black Widow woofers, 2 in each cabinet.  The cabinets are pretty solidly built.  The cabinets are slot ported and each woofer is in its own 'chamber' in the cabinets.

Would I see any kind of benefit at all by going to better woofers in them?  I know that you can't just toss woofers in a cabinet and expect amazing results.  I attached a picture of them for reference (with my little woofer in between them).

 

At one time I had a link to an old Peavey catalog that gave the specs as far as frequency response and sensitivity for them.  Not sure I have that anymore.  I believe each cabinet was rated at 99dB sensitivity and +- 3dB 40Hz-200Hz but I could be way off.

My ultimate goal would be to result in a lower -3dB point, mainly for home theater purposes.  Would the cabinets themselves be a limiting factor in accomplishing this?

[Khornukopia]

I once replaced a Black Widow driver with a Peavey Low Rider 18" subwoofer driver and it was a big improvement in low frequency response. 

 

[wuzzzer]

Anyone else?  What would be the best way to determine what woofers would work the best?

[RoboKlipsch]

In a ported box a woofer wants a specific size enclosure to have a smooth response.  You would want to measure the box dimensions, estimate the displacement of the slot port and drivers and subtract those in order to come up with a net cabinet volume.

 

Then search for a driver that has -- the same size cutout, a lower Fs (-3db spec) and models well in that net volume.  Since there are 2 subs per box make sure to divide the net by 2 to get the volume per driver.

 

You could have a hugely improved set of subs but as described above it will require some searching to find a suitable driver.  The tip above about a low rider may give you a nice shortcut if the specs work in those boxes.

 

What you have now is a pro style sub setup built for big volume and not a lot.of low end.  

[JohnA]

You've got a tough job.  I doubt you can lower the f3 because the box volume is set, but you should be able to find woofers that distort less and absorb more power.  You might get a little more bottom out of them, with a ripple, by lengthening the ports.  Measure your inside dimensions and port size and length and call Eminence.  They have been helpful in the past with such inquiries.