The internal crossovers on most amps are fine, if they do the job and do
not
introduce noise then I use them. You are more likely to introduce noise
by
adding extra components like external EQs and crossovers.

There is nothing that I hate more then built-in x-overs especially when it
comes to bi-amping subwoofers.

What other solution is there, if you insist on biamping a subwoofer? Head
unit filtered outputs? Not all heads have them.

There is nothing that I hate more then trying
to tune a pair of amps with an oscilloscope and a tone generator, because
on
average it takes me a better part of a week to tune a system with just a
single amps per each sound range.

That's why I never biamp a sub. I can't think of many reasons why you would
have to, unless you're into some really exotic dB drag stuff.

With an external x-over I can run 10
amplifiers to power my subs and I know that all of them are running at the
same frequencies. I have an Audiocontrol 4xs x-over that I hold very
dear,
with this thing no matter what plain-jane amp I happen to come across has
a
2/3/4 way x-over with a selectable 18 dB/24 db roll-off.

I had to get rid of my 4xs because it didn't provide as much adjustability
as my a/d/s/ amp's xovers.

Along with an
adjustable subsonic filter, Adjustable, balanced or unbalanced inputs, and
selectable ground loop isolation (isolated, grounded or 200ohm). That's
all
the x-over that I have ever needed.

The subsonic filter is a nice touch.


Reliability, how can you tell from one amp to another? Look at the nasty
surprise PPI fans got when they upgraded from the PC line to the newer
PCX
line, who seen that coming.

If a company has consistently put out a solid product the chances are
that they
will continue to do so. Though there are instances where that is not the
case.
You also have amps that have established themselves that you can buy
used.


Price and resale value goes hand and hand, if you pay next to nothing
for an
amp you'll get next to nothing on the resale market.

Some amps hold resale value better than others, some have virtually no
resale
value. That is why you have to weigh the costs on each.

You cannot have the best in all of the catergories. Choosing an amp has
many
facets and noone needs the myth of Sound Quality mucking it up.

What are your reasons/thoughts when buying an amp?

Les

I'm not overly picky about the amps that I use to power mid/highs with,
but
when it comes to powering low end that's a different story. I like amps
that
are totally featureless in the way of x-overs, bass boost, and overload
protection. I look for amps that will run at low impedance. Amps that
have a
high fuse rating vs rated wattage. Although I wouldn't pass on a good amp
without a built in cooling fan, I definitely much rather have an amp that
has
one. I also tend to buy big sled amps not only because of the cooling
factor,
I just like the pure size of them. As for class a/b vs class d when
looking at
sub amps, I have too many mixed emotions on the issue.

Where does the airy nature of the sub amp, the high damping factor, the
warmth of the sound, and the precision of the control of the cone come into
play?