Biamping 802 Diamonds?

[audiomania]

I'm not sure why there is mention of needing an active crossover and things of that nature in order to BiAmp your 802's. I'm currently doing this as mentioned in my post earlier by way of a Classe CP-800 PreAmp and letting the internal speaker crossovers handle the signal separation. I'm feeding each pair of terminals on the back of the speaker a full range signal from the PreAmp and this is working very well for me. The built-in PreAmp volume control is handling the levels of all Amps. All amps are very closely matched though in terms of there output signal which I would say is definitely a requirement.

Before I took on this method of connectivity I confirmed doing things this way by emailing and having a conversation with B&W Support who said this is a perfectly acceptable way of BiAmping.

I can tell you from experience that there was a large difference in SQ for the better afterwards under any and all conditions. Prior to BiAmping, I was using the standard approach of BiWiring using only X 2 Monoblocs so I am very familiar with how the differences sound when comparing the two approaches.

Now there is one thing I would say you do need and that is X 2 pairs of Balanced Outputs on your PreAmp in order to accomplish this correctly. Both pairs of Outputs should be able to send a full range signal with adequate voltage to drive the Amps in question.

Again, I am not using an Active Crossover to accomplish this. Would an active crossover be better? Probably. Is it needed? No.

[Art Vandelay]

Originally Posted by audiomania

Again, I am not using an Active Crossover to accomplish this. Would an active crossover be better? Probably. Is it needed? No.

Actually, an active crossover wouldn't be better than a well designed passive one that's been tuned to fit the driver responses.

The way you're bi-amping is perfectly correct.

[GaryProtein]

Sending full range signals to drivers that cannot use it is a waste of power and without an active crossover, you also lose the direct control the amplifier has with the speaker driver with all the parts in a passive crossover intervening.

You can use multiple amplifiers to drive a speaker, but will only realize the improvements with an active crossover. Why do you want to send 5000Hz to a woofer that operates for example between 20-150 Hz? or 20 Hz to a midrange and tweeter?

If you are going to multi-amplify, you should do it right. There is more to multi-amping than hooking up more amplifiers to a speaker.

Re-read my post copied from the B&W website.

[Art Vandelay]

Originally Posted by GaryProtein

Sending full range signals to drivers that cannot use it is a waste of power and without an active crossover, you also lose the direct control the amplifier has with the speaker driver with all the parts in a passive crossover intervening.

You can use multiple amplifiers to drive a speaker, but will only realize the improvements with an active crossover. Why do you want to send 5000Hz to a woofer that operates for example between 20-150 Hz? or 20 Hz to a midrange and tweeter?

If you are going to multi-amplify, you should do it right. There is more to multi-amping than hooking up more amplifiers to a speaker.

Re-read my post copied from the B&W website.

When you drive the woofer ports of the speakers in a bi-amped configuration, the impedance rises above the crossover point proportional to the slope of the filter, so there's almost no power dissipated at mid frequencies and above.

Similarly, when driving the mids + tweeters, the impedance rises below the crossover point, so even though the amplifiers is outputting voltage at bass frequencies it's not outputting any current so it's not dissipating power.

Bi-amping speakers with passive crossovers is definitely a valid method of reducing amplifier loading, and it also allows the user to chose the most desirable amplifiers for mid / treble and bass duties.

[RebelMan]

Originally Posted by GaryProtein

The bi-wiring statement in the first paragraph is bullcrap--a lie. Bi-wiring is solely a way the dealer can sell you more cables.

The last paragraph is true. That is why I said to sell your present amps and buy a pair of bigger amps.

Actually, the first paragraph is true. Bi-wiring B&W speakers (with parallel runs) does in fact improve imaging and resolution most notably throughout the upper bass and midrange. Passively bi-amping B&W speakers provides no additional benefit beyond bi-wiring other than the potential for higher output. I've tested this extensively. It really only makes sense to passively bi-amp the B&W's when you want more power but don't want to part with the amplifier you already have. Or you are looking to one up the max power available from your manufacture of choice. In both cases the amplifiers should be identical for optimal results.

[Rod#S]

My opinion is if you are noticing a difference in bi-wiring then that's saying you need a more powerful single amp.

[microstrip]

Originally Posted by Art Vandelay

When you drive the woofer ports of the speakers in a bi-amped configuration, the impedance rises above the crossover point proportional to the slope of the filter, so there's almost no power dissipated at mid frequencies and above.

Similarly, when driving the mids + tweeters, the impedance rises below the crossover point, so even though the amplifiers is outputting voltage at bass frequencies it's not outputting any current so it's not dissipating power.

Bi-amping speakers with passive crossovers is definitely a valid method of reducing amplifier loading, and it also allows the user to chose the most desirable amplifiers for mid / treble and bass duties.

I fully agree with you. Many people forget that amplifiers must deliver current and usually their performance suffers when they must deliver high currents. Using separate amplifiers allows them to work in better conditions. This is particularly important if your music has lots of energy in the bass, where modern speakers have usually significant impedance dips.

I never had success using different amplifiers in a bi-amplification, but had excellent results long ago using two stereo Electrocompaniet AW100 amplifiers in bi-amp with BW 802's. And I preferred the sound of the pair of AW100's to that of the single AW250.

[RebelMan]

Originally Posted by Rod#S

My opinion is if you are noticing a difference in bi-wiring then that's saying you need a more powerful single amp.

Negative. Tests were contucted with high current 100-400wpc amplifiers that could double down. Using high quality, load matching, conductors (and they can be inexpensive to procure) yields real results. Speaking for B&W's it would be a bigger mistake not too.

[audiomania]

Originally Posted by RebelMan

Passively bi-amping B&W speakers provides no additional benefit beyond bi-wiring other than the potential for higher output. I've tested this extensively.

Dunno, but having enough Amp to feed a speaker known to "love" allot of power seems like a pretty big benefit from where I'm sitting and to these ears active crossovers or not

I find it interesting there is such a wide range of differing experiences being reported on this subject (though I probably shouldn't be suprised, this is the Internet Afterall).

Clearly no one is going to win this showdown

[Rod#S]

Originally Posted by RebelMan

Negative. Tests were contucted with high current 100-400wpc amplifiers that could double down. Using high quality, load matching, conductors (and they can be inexpensive to procure) yields real results. Speaking for B&W's it would be a bigger mistake not too.

Been there, tried it, going to a single Bryston 28B-SST2 made more of a difference than Bi-amping with dual 4B-SST's. Parallel bi-wiring with the separate output terminals from the 28's yielded no improvement over the single cable run.