After upgrading my main HT sub to a Velodyne SPL 12 Series II, I am left with a couple of Polk subs - a PSW250 (8 inch) and a PSW450 (12 inch) to play with for a bedroom setup. I am exploring the possibility of upgrading the driver in one of these and get it to produce higher quality bass output. Any experience out there experimenting with this type of upgrade in general? Part of me tells me this is a fools errand as Polk designed the enclousure specifically for the driver they use, but on the other hand, it can't hurt to experiment with relatively inexpensive sub drivers out there like the Selenium sw2 series - worse case I can buy some wood and have fun building a new enclousure if the Polk chassis does not work out. Thoughts?

"Namikis" wrote in message
...
After upgrading my main HT sub to a Velodyne SPL 12 Series II, I am left
with a couple of Polk subs - a PSW250 (8 inch) and a PSW450 (12 inch) to
play with for a bedroom setup. I am exploring the possibility of upgrading
the driver in one of these and get it to produce higher quality bass output.
Any experience out there experimenting with this type of upgrade in general?
Part of me tells me this is a fools errand as Polk designed the enclousure
specifically for the driver they use, but on the other hand, it can't hurt
to experiment with relatively inexpensive sub drivers out there like the
Selenium sw2 series - worse case I can buy some wood and have fun building a
new enclousure if the Polk chassis does not work out. Thoughts?

Sounds like fun, but I doubt if you'll get any benefit. Are the Polks
powered? If so, you might want to play with just the amplifier, driving a
larger sub...although there are probably more flexible sub-amps to be found
from places like Parts Express. The x-over point and curve are probably
matched to the Polk driver/enclosure.

If you're hankerin' to build, sell the Polks and start from scratch.

jak

"jakdedert" wrote in message
. ..

(snip)

Sounds like fun, but I doubt if you'll get any benefit. Are the
Polks
powered? If so, you might want to play with just the amplifier,
driving a
larger sub...although there are probably more flexible sub-amps to
be found
from places like Parts Express. The x-over point and curve are
probably
matched to the Polk driver/enclosure.

If you're hankerin' to build, sell the Polks and start from scratch.

jak

Over the last 2 months I have bought two PartsExpress sub. amps. model
"300-804". I am very impressed with this model. It's a class AB
linear of some 200 watts into 4 ohms, 150 watts into 8 ohms. One of
mine drives a salvaged Infinity 12 inch passive sub (in which the
flimsy Class D amp. died noisily!) and the other is on my electronic
piano driving two Energy ESUB2's (rather small passive subs) in
parallel through a matching auto transformer to get 7 ohms impedance.
Not low enough response (the speakers, not the amp.) so the it will be
changed to a second passive 12 inch sub. or bigger when I get around
to it.

BTW, I am now gun shy of most commercial powered subs, especially the
cheap class D stuff. IMHO you get better value building your own
closed box and large driver and buying a linear power amp.

Cheers,

Roger

Engineer wrote:
"jakdedert" wrote in message
. ..

(snip)

Sounds like fun, but I doubt if you'll get any benefit. Are the
Polks
powered? If so, you might want to play with just the amplifier,
driving a
larger sub...although there are probably more flexible sub-amps to
be found
from places like Parts Express. The x-over point and curve are
probably
matched to the Polk driver/enclosure.

If you're hankerin' to build, sell the Polks and start from scratch.

jak

Over the last 2 months I have bought two PartsExpress sub. amps. model
"300-804". I am very impressed with this model. It's a class AB
linear of some 200 watts into 4 ohms, 150 watts into 8 ohms. One of
mine drives a salvaged Infinity 12 inch passive sub (in which the
flimsy Class D amp. died noisily!) and the other is on my electronic
piano driving two Energy ESUB2's (rather small passive subs) in
parallel through a matching auto transformer to get 7 ohms impedance.
Not low enough response (the speakers, not the amp.) so the it will be
changed to a second passive 12 inch sub. or bigger when I get around
to it.

BTW, I am now gun shy of most commercial powered subs, especially the
cheap class D stuff. IMHO you get better value building your own
closed box and large driver and buying a linear power amp.

I was under the impression that the Parts Express sub amps were merely
manufacturers over-runs, produced for a commercially available sub. Not
true?

Having said that, between my OP and now (yesterday, to be precise), I picked
up a functioning KLH powered 10" sub for $20. Now I'm in the same mode as
the OP. The amp has a variable x-over point, phase is reversable, low level
& speaker level ins/outs. I'm assuming it puts out around 75 watts based on
the stated a.c. draw of 130 watts.

It sounds 'okay' as-is, but I wonder what a better driver would do in the fr
ont-firing, dual ported box...or how the amp would perform with a totally
different box/driver combo. 75 watts is not much power, so I might not even
mess with it. It's currently mated to my stereo receiver and a pair of
vintage 10" HH Scott 2-ways, using the high-level ins/outs.

Question? is there normally any h-p filtering in the passive 'thru' speaker
outs? I haven't done any testing or inspection to determine so--no time.
If so, I might parallel the l/r speakers as they have a pretty robust bottom
end on their own.

jak

Cheers,

Roger