"mike vandy" wrote in message
m...
I'm confused about a certain issue. What is the best amplification
for
a DIY subwoofer. I know the official answer is "IT DEPENDS". I guess
what I'm asking is... should I buy a subwoofer amp (with phase, and
low pass filter, volume, etc.).. or should would I get better
results
with an external amp?

It seems strange to me that most subwoofer diy projects use built in
amps, which cost 150 bucks or so. On the other hand, amplifiers for
high end audio routinely cost much much more. Is a 200 dollar
subwoofer amp really as good as building a passive sub and attaching
a
1000 dollar external amp to it?

You don't need $1000 amps for this!

You can get up to about 100 watts of cheap subwoofer power from a
surplus 50 wpc vintage stereo receiver IF you have two passive subs or
a single sub that has two drivers in the same box - just wire them
independently to L and R channels and drive the amp in mono. Of
course, NEVER wire amplifier O/P's is parallel. You can get even more
power from a separate stereo amplifier (I use a Yamaha M4 to drive two
separate passive subs, up to over 300 watts total.) But here's the
rub, you will likely have to find a LP filter to put before the sub
amplifier AUX input.

If you use a stereo receiver or so-called integrated amplifier (with
pre-amp) the sub-out level from a surround sound receiver will be
about right and it is already LP filtered (but likely at a bit too
high crossover, but that's another matter.) The stereo amps alone
need an external pre-amp and a LP filter if you drive them with full
range L and R signals (I had to build a pre-amp and 90 Hz LP filter to
get the over 1 volt RMS needed by the M4 from a Yamaha receiver
sub-out channel with a 150 Hz X/O.)

Cheers,

Roger