Bi-Amping 802d's

[Chelseaforever]

I have just added another Bryston 4BSST to my system thus Bi-Amping my 802's. I am absolutely blown away by the results. It takes the 802d's to a completely different level. Mid-range and treble have been elivated to an entirely new level of refinement, at the same time the bass is firmer with much greater control. The soundstage has also become panoramic by comparison. I cannot believe the leap this upgrade has made. I also tried them in bridged mono mode but the result was less pleasing than bi-amping.

Kit:
2 x Bryston 4BSST, Naim - CDS2, XPS, NAC 52, Supercap, AV2, 2 x NAP 140,
Naim Fraim, B&W - 802d, 805s, Castle - Richmond & Sub, Pioneer - PDP434PE, DVD868, Sky +, Xbox 360.

[Karma]

HI Chelsea,
Biamping B&W 800 series speakers has been the subject of several recent interesting threads. Not everyone agrees that it is the way to go. Much of the controversy revolves around the way the biamping is implemented.

How are you doing it? Are you simply driving each speaker terminal with separate amplifiers that use an identical, split input signal and using the internal speaker crossovers? I'll bet this is your case. This is not classical biamping but I don't know what else to call it.

The other, and more controversial case, involves bypassing the internal speaker crossovers and providing the crossover function in front of the amps using active, line level crossovers. This is classical biamping. Are you doing this?

Inquiring minds want to know.

Sparky

[Chelseaforever]

I am using the first of your two options and it definately works wonders. I was fairly sceptical about the benefits it would deliver but a home demo by my dealer (Soundcraft, Kent, UK) left me in no doubt. As i said the only other option we tried was running both amps in bridged mono mode. This certainly gave an amazing sense of power but didn't give the level of refinement to the mid/treble range. I guess running 4 in bridged mono would be the answer if funds and space allowed.

[kurtholz]

i agree with chelseaforever, i recently bought a krell 5 channel theater standard, i am bi-amping it with 4 channels from the krell, it is an absolute huge gain in sound image ,quality,bass etc, i am using 803's, a very interesting issue is i was using a kav3250, ( same watts per channel) driving my front three, in a bi-wire configuration, now relegated to the rear channels, but i had to wait a few days to get the xlr splitters to bi-amp, the standard ,it was still an upgrade over the kav series, as i bi-amped it at first, same wattage but different model krell, i found this to be a surprise, that the different krell models were so different in sound

Kurt

[tboooe]

This is very interesting to me. Is there any reason why biamping in this manner yields such good results? Is it because there is more power being fed to each speaker post? Also, does splitting the signal cause any degradation in the signal? I assume people are using high quality splitters.

[Chelseaforever]

From my NAC 52 pre-amp there are two outputs feeding the two power amps, so the signal isn't actually split, each of the amps recieves exactly the same signal. I don't know the technical reason for the vast improvement made but I actually was tempted to try it after reading other experiences here on this forum.

[dknightd]

My theory is that by biamping, even passively biamping, that each half of the speaker is uneffected by the other half. So, for example, if the bass drivers
are putting a large load on the amplifier, it will not effect the midrange
and treble because they are using a functionally seperate amp. On one
level this makes sense, on a nother level it doesn't. Kind of the way
of the world these days. . .

I'm interested in inexpensive splitters, since my preamp does not have
splitters built in, and, I might like to try biamping.

[tboooe]

if this works how about taking it to the next level and using 4 monoblocks, one for each post on the B&W speakers?

[Chelseaforever]

This must be the ultimate answer, and I would just love to hear it.

[Aussie Geoff]

if this works how about taking it to the next level and using 4 monoblocks, one for each post on the B&W speakers?

Sorry - for an amp to work it needs an complete electrical connection (ie a postive and negative link). If each amp only had one of its termnials connected to the speaker there would not be a proper circuit and the current would try and flow between the amps (e.g. out of the postive from one amp into the negative of the other via the speaker terminals) - with results likely dangerous to the amps unless they were specially designed for this.... Certainly there would be no improvement in the sound.. indeed there may not be any sound produced...

[tboooe]

aussie geoff: sorry I meant one amp for each PAIR of speaker posts since B&W have 2 sets on each speaker.

[sikoniko]

I read recently an interesting article on this. The question was, is it more beneficial to biamp (passively) 2 300w amps or just use 1 600w amp.

The answer was, if you are using 2 amps, true one is pulling power and not effecting the other, but the downside was that each section could only use a max of 300w, whereas, in a 1 600w amp, if the mid and tweet was only using 200w, there would be 400w available for the bass drivers.

with that being said, one of the members, Dan (dont remember his handle) used the 600w bryston (6b?) for his bass drivers and the 300w drivers on his mid/highs for passive biamp setup on N802's and claimed a significant benefit over even a pair of 4b's's biamped.

[kurtholz]

well, i can't say why it works, but it does on my system, i did the biwire, then the bi-amp, same music, just to see, i think that pushing somewhere around 800 watts thru each speaker makes the difference,assuming my 803's are basically at 4ohms most of the time,

i experienced basically the same thing when i went from a Rotel 1075 to a 1095, huge sound improvement

i also tried the Rotel up front bi-amp, the Krell even though it is rated at the same watts does such a better job,

the big surprise was using the Krell kav 3250 bi-wire on the front three( 200 watts at 8ohms, double at 4 ohms) then using the Home theater standard,( same watts) and hearing just a slight improvement in the upper frequencies, and a more quiet soundstage, with a very improved deep black soundstage, very precise

then bi-amping it made a very noticable difference in everything

of course, it is an extreme dose of limiting returns, comparing a $7500 amp ( krell) to a $2000 Rotel, there is a difference but very little, the Rotel just has a little bit of grain in the sound and doesnt have the feel of power like the Krell, it does have a bit of noise and not as musical,

also, the Krell seems to push more power out, the Rotel i could crank up to 55 - 60 on the dial, the Krell at 45 is significantly more thunderous, it's scary almost as there is no sense of strain at all, not sure how loud it could go without loosing the musicality factor,

well, gotta crank it up, hope the plaster can take it

:-)

Kurt

[PavelL]

with that being said, one of the members, Dan (dont remember his handle) used the 600w bryston (6b?) for his bass drivers and the 300w drivers on his mid/highs for passive biamp setup on N802's and claimed a significant benefit over even a pair of 4b's's biamped.

If that is Dan Schulze you are reffering to then this is what he PMed me "I was shocked how bi-amping helped the sound from my 802's. To be honest, I did not expect much difference, since I was using good amps already (Bryston 7B SST's - one for each of my two 802's).

I have 2-7B SST's, a 6B SST, and a 4B SST. I did try using the 4B SST and the 6B SST to bi-amp the 802's, since I had a request from a fellow forum member to try that combo, as he was going to be using 2-4B SST's for his setup. Quite frankly I did not notice a difference whether I used the 4B SST and the 6B SST, or the 2-7B SST's and the 4B SST to bi-amp the 802's. Since I already had the 7B SST's, I figured I would just use them to bi-amp my 802's along with either the 6B SST or the 4B SST.

I chose to use the 7B SST's for the low frequencies and my 6B SST for the high frequencies. I am using the 4B SST to bi-amp my HTM1 center channel. The reason I chose the 7B SST's for the low frequencies, is because I anticipated the need would be greater from the bass drivers, although if I had to do it over (knowing what I do now about bi-amping), I would have bought another 4B SST instead of 2-7B SST's, simply for economic reasons and like I said before, I did not notice any difference when I used the 4B SST/6B SST combo."
:T

[james_dmi]

The other forum member who made the request was me. Dan was great running this experiment with his expensive kit just for my benefit. He did not expect the results he got and before he tried had no plans to bi-amp. Thanks to me he had yet more expensive hifi purchases to make, but I don’t think he was that upset.

My first Bryston 4B-SST arrives tomorrow the 802D's will follow in a few weeks. I will then be adding a second 4B-SST in a few months time (once funds recover). I have had a few bi-amp configurations in the past and have chosen these over bigger single amp configurations after comparative testing. Both have benefits but for me I find bi-amping with two lesser amps can often beat the big amp

[sikoniko]

cool! Im glad to get this info out. I plan on biamping a pair of nuforce ref9's myself.