should i bi-amp using my 5ch amp, or upgrade?

[remcoy]

i moved from surround to 2 channel a while back, so i was thinking of swapping my RB-985 100x5 amp for a dedicated 2ch amp. RB-1070 or 1080 maybe, to drive a pair of B&W Matrix 805s. I was wondering if maybe i would just be better using the 985 to bi-amp the 805's. Do you think i would be missing out on anything.. would this solution have a benefit in sound? over a proper 2 channel?

[soundhound]

Active crossovers come pretty reasonable, audigon, ebay. etc.... It may be worth buying one and trying bi-amping. You will notice a difference over letting you're speaker crossovers doing duty. It will come down to which you prefer, and you can allways get you're money back on components if you buy descent brands at reasonable prices.

[csuzor]

Is it worthwhile to use an active crossover (crossover before amplification), without overriding the internal crossover inside the speaker itself? Is there a risk that the external active crossover will not be set at exactly the same level as the internal crossover, leading to a dip in frequency response?
The easy solution would be to biamp without adding an additional crossover, unless you can remove the internal crossover and set the same crossover frequencies before the amp. The advantage then is more limited, and maybe not worthwhile.

[soundhound]

In my perception, the sole purpose of bi-amping is to narrow the bandwidth that an amps channels have to drive. If you actively cross over b-4 amplifying you demand less of the circuitry, so it should do better, or at least have an easier time doing what it does. Manufacturer's of active crossovers overlap frequencies at their points so you don't get "voids" in the sound. Bi-wiring, again in my perception, does nothing, except if someone says they hear sonic benefit, I believe they need a little heavier guage wire to begin with. Essentially all that does is parallel speaker wires. Circuirty remains the same. And when you do bi-amp or bi-wire either one, yes, remove the jumpers on you're speaks as that is hard on amplifiers.

[booktrunk]

I think that you might as well bi-amp with the 985 as go for a sole 1070.

But the step up to a 1080 would be appreciated by the B&W 805s.

I've had a 991, 1070s and 985 mk ii and played with all of them and think that there is little between the 1070 and 985 but he 200w amps are that bit nicer.

Steff

[mjb]

Soundhound, good advise :T

Let me add, when using an active cross-over, the speakers internal cross-over should always be removed - its function is replaced by the active crossover. Therefore the cross-over frequencies of an active cross-over must be matched to the individual speakers natural range (pass-band).

If you bi-amp without an active crossover, the full (amplified) frequency range will be sent to tweaters and woofers alike, so there's little little advantage other than more power.

If bi-wiring sounds better, then you needed heavier cable in the first place.

[NewBuyer]

...If you bi-amp without an active crossover, the full (amplified) frequency range will be sent to tweaters and woofers alike, so there's little little advantage other than more power...

But more (quality) power can be an advantage though, yes? Wouldn't passive biamping (with a quality amp of course) cause a good speaker to sound much better at low volumes?

[mjb]

Wouldn't passive biamping (with a quality amp of course) cause a good speaker to sound much better at low volumes?

Arguably it might! Try it, if you are happy with the result, then great. Don't forget to remove the speakers bridging clips though.

Here is a good article on bi-amping: http://sound.westhost.com/bi-amp.htm