[barkingfinch]

I just have upgraded speakers to B&W 702 s2 speakers.  Previous speakers were not able to be bi-wired, but these are.  The amplifier is a Marantz PM8005.  I don’t know a lot about electrical requirements.  The new speakers are 8 ohm nominal, 3.1 minimum.  The old ones, NHT 2.5, were said to be 4 ohm, with no further elaboration.  The amplifier speaker connections state that if you use 2 pairs of speakers, 8 ohms is the minimum for two pairs.  Of course this would not be two pairs of speakers but one pair bi-wired.

Can you enlighten me about bi-wiring being wise or feasible with this amp?  By the way, not quite ready to upgrade the amp yet.  Many thanks.

[FullRangeMan]

Welcome
Sorry for this unsuited speaker, no many amps can drive a 3 ohms load,  the nominal 4 ohms is marketing.

[opnly bafld]

Remove the jumpers from the posts of the speakers and run 2 sets of wire from A and B on the amplifier.

[toocool4]

I can only speak from my own experience, so here goes I have bi-wired before and it’s a complete waste of money. But when I bi-amped, now that was a completely different story totally worth the extra expense. The sound vastly improved.
Since your amp is an integrated, you can’t bi-amp with it.

[kernelbob]

Regarding the impedance warning on the amplifier, this concerns running two pairs of speakers in parallel.  That is, the amplifier's output stage is driving a pair of A-speakers and a pair of B-speakers in parallel.  It has nothing to do with driving one pair of speakers that are designed to support bi-wiring or bi-amping. A speaker that is designed for bi-wiring has one set of terminals that connect to the mid/treble crossover and another set of terminals that connect to the bass driver(s) crossover.  The excluded frequency range of each crossover has very high impedance to prevent transmitting frequencies not suitable for the driver(s).  The result is that the mid/treble crossover has very high impedance in the bass frequency range.  The bass drivers' crossover has very high impedance in the mid/treble range.

The benefit is that the relatively high voltage swings in the bass frequencies are isolated from the mid/treble signal.  This avoids these relatively high bass voltage signals from modulating the mid/treble signal.

Those same two pairs of input terminals can also support input from two difference amplifiers.  My speakers use dynamic drivers for the bass and midrange with a ribbon tweeter.  As with most dynamic drivers, they perform best with an amplifier that has very low output impedance (i.e. high damping factor) typically with a amplifier with a very fast feedback architecture.  This is the domain of the bass input pair.  The midrange/treble input doesn't need that feedback control.  In my system, these are driven with monoblock tube amps which use no feedback, neither global nor local.  In short, "horses for courses".  A side benefit is that since the impedance of the power hungry bass drivers as seen by the mid/treble amplifier is very high, the amplifier is not required to consume precious watts driving bass drivers.  This may allow a low powered tube amp to perform well in this role when they would have insufficient power to drive the same speakers full range.

One possible thorn in the configuration is if the two high and low range amplifiers have significantly different signal throughput times.  In other words, how much time does each top and bottom amplifier take to process the signal and output it to the speakers.  I've not had any issues with this.  The resulting aural image in my system (several different speakers and amps) is seamless, i.e. I cannot identifiy any sonic decoherence between the bass and mid/treble ranges.

Hope this helps.
Robert

[jonbee]

I've had many biwireable speakers over the years. It has made little or no difference on some speakers, and a transformative difference on others. I can't predict which work best. I encourage you to try it in the easiest way from your amp and see how it works for you.

[Greggo1545]

I've had several Bowers & Wilkins speakers including the CM6 S2, CM10 S2, 805 D, and now the 805 D3.  I'd say that bi-wiring is beneficial but something else to consider is upgrading your jumper cables instead.  Kimber, Anti-Cable, and others sell jumpers and I believe they add a some benefit although it isn't night and day - more like the difference between dusk and night.  I currently use the Kimber Kable 12TC which is a bi-wire cable but have used Kimber & Anti-Cable jumpers in the past that were pretty good.

[ArthurDent]

Greetings & Welcome to AC barkingfinch   

[Phil A]

Welcome!

[kernelbob]

Regarding biwire versus single connection with jumpers, improving the wire of a jumper would never be a bad idea.  However, using jumpers doesn't isolate the bass inputs from the mid/treble inputs.  The crossover network behind the separated mid/treble input has very high resistance in the bass frequencies.  This is what prevents significant bass signal's current from being conducted through the mid/treble cables.  It's that otherwise relatively high current (compared with mid/treble frequencies) that would otherwise modulate the mid/treble signal.  No jumper is used between the two sets of terminals of course.

Unless the cost is prohibitive, you can purchase two completely independent sets of cables.  That way you can connect both cables to the same amplifier terminals and separately connect one set to the bass and the other set to the mid/treble speaker inputs.  This gives you the maximum flexibility going forward, biwiring now with the option to biamplify if you later choose with no additional changes to your cables, just connecting one set to the top amp and the other set to the bottom amp.  I always use cables with spades on one end and bananas on the other.  This supports biwiring by reversing one set of cables with one set's spade connector and the other set's banana connector at the amp terminal.  That way you don't have to piggyback spades at the amp.

[knotscott]

Give it a try.  The cost is an extra set of wires, shouldn't hurt anything, and just might make an audible improvement.