I'm not familiar with your amp at all, but when you say "mono amp" that
says to me that your amp has *one* channel ("mono" == "one"), so I'm
not sure what kind of beast you're describing with two channels. It
sounds like perhaps you're using a two-channel amplifier in a "bridged"
configuration (e.g. by using a "+" from each channel or a "+" from one
channel and a "-" from the other).
A somewhat technical explanation of what's going on here can be found
on wikipedia:

http://en.wikipedia.org/wiki/Bridged_amplifier

In essence, you combine the two channels such that the the voltage
swing across the two terminals is double that of a single channel--a
feat which can be accomplished, by the way, ONLY on amplifiers designed
for this mode of operation. These days, almost all car audio amps are
bridgeable, but I say this to be thorough.

*toke* *toke* *toke* "The colors, man....the COLORS!" Either your
recollection of what "someone at Best Buy" (was this a customer???)
said, or the individual you spoke with is seriously confused. It sounds
like someone's been reading too much Car Audio & Electronics without
having actually worked on an electrical circuit of any sort.

When you bridge an amplifier, each half of the bridged pair "sees"
exactly half of the load. So, if you present a nominal 4 Ohm load to a
bridged amplifier, each channel "sees" 2 Ohms--this is why you always
see amplifier power specs say something like "100W x 2 @ 2 Ohms; 200W x
1 @ 4 Ohms". A bridgeable amp that is "two Ohm (stereo) stable" can, at
most, be 4 Ohm mono stable. Make sense?

So, if you have a single subwoofer to run with a single amplifier, you
have three options:

   1. Run the amp in "stereo" (unbridged) mode with a mono
(non-stereo) input. This
       will present a 4 Ohm load to each side of the amp;

   2. Wire the voice coils in series to produce an 8 Ohm load and
bridge the amp, hooking
       it up to the subwoofer as directed by your amplifier's manual.
This presents an 8 Ohm
       mono load to the amp, which is identical to option #1, above;
or

   3. Wire the voice coils in parallel to produce a 2 Ohm load, thus
presenting a 1 Ohm load
       to each channel, which will almost assuredly void your warranty
and lead to seriously
       shortened life expectancy of your amp's power supply and output
transistors.

   4. Exchange your sub for the one you need.

The lesson to take away from this is DO NOT GET GREEDY. If you try to
get more out of your amp than what it was designed to produce, you
*will* pay for it...and it won't be cheap.

-dan

Sounds like the BB person is confused or ignorant or both. If you do
indeed have a mono amplifier, it cannot be bridged. The two sets of
speaker connectors are purely for wiring ease and aesthetics. If you
connect one VC to one output, and the other to the second, it will be
the same as wiring both to one output. I.E. parallel wiring. All my mono
Class D sub amps since 1999 have been this way.

Brandonb

Alrighty... thanks again.

I guess i am curious as to why the kenwood amp has the same RMS at 1O.
Maybe the manufacturer just keeps it there to prevent the THD from
going over 1%. If they can even rate their own amps output...

reminder: i have an alpine type-r, 500 watts RMS.

So would i be better with keeping what i got and going 900 RMS at 2O
with one sub, and then 450 RMS each with two subs at 1O if and when i
get another one...

OR

should i try to get some money back for the 4O DVC and get the 2O DVC
model. Then i would have 500 RMS at 4O with one sub, and again, 450
RMS each at 2O  with 2 subs, and a little less THD.

would i even be able to tell the differece?
i as never worried abotu hurting my amp as i knew it was 1O stable, i
just wanted SQ.

thanks man, you're helping me out a lot here.