BiBi

Pfdjr1

What exactly is bi-amping, and what are the benefits? And how do you do it?
Are tow subs ever really needed, if so for what??

McLoki

Bi-amping. Using 2 separate amplifiers one for the high frequency range, and one for the lows. It allows you a couple of things including protecting the tweeter from burnout when clipping on the bass signal. It also allows you to talor the sound to the amps being used. (tubes on top, SS for solid bass)

It is rarely implemented corrected and almost never cheaply. Due to that, the benefits will vary depending on speakers, amps, rooms and associated equipment. (if the amp is not a weak link in your system - you will not see as much benefit)

99% of the time it is not worth the effort or expense over just getting a decent amp to start with and run with that.

Is any sub ever really needed? (or home theater for that matter - doesn't you TV have speakers???)

Now that the obvious is out of the way - there are a few really good reasons to run multiple subs.

1) Rooms play havoc with bass signals. Multiple subs if placed apart from each other (or opposite each other in a room) will help smooth out the frequency respose of bass in the room - making for a much wider sweet spot and smoother frequency response.
2) Voice coils heat up as a speakers moves and subs move more than most speakers. (due to the nature of reproducing bass) This can cause distortion in a bass heavy movie even if your sub is playing within its limits. Adding a separte sub and co-locating it with your primary one produces 6db more signal. This is the equivilent of running an amp with 4X less power.

If a bass hit requires 200 watts from the amp - with dual co-located subs calibrated to the same volume - it will only need 50 watts. (with dual subs not co-located - it would require 100 watts as dual non-colocated subs will give you about 3db of gain).

3) Also you have to move air to produce good bass. In a large room - that can be very difficult. To get the strong slam or punch inthe chest feeling you get at a concert - your subs need to be able to move alot of air (subs can do more than just produce a frequency at a certain volume - They can also "control the air" in the room.) Multiple subs located closer to you have a better chance of doing this than a single sub across the room.

4) Last but not least - much like when talking about amps - headroom is your friend. To accurately reproduce bass in a movie - the sub has to be able to pull it off at any frequency or volume you want and sound completely efforless doing it. Alot of subs can produce bass - only the great ones (or maybe pairs or quads of the medium ones) can pull off all of what I mentioned here.

Do you NEED two subs No..... But once you hear them in your environment, theres a good chance you will WANT them.

Michael

BTW - Welcome to Club Polk.

Pfdjr1

Thanks