What does the crossover do differently when you bi-wire?

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My Mission 701 had just two speaker terminals. I cut the tracks on the crossover pcb and separated the bass and hf section and fixed a bi-wireable socket. To my ears they did sound better bi-wired. Bi-amped they went much louder too and appeared to sound cleaner at that high volume.

Note that though the voltage signals on the wires are identical the currents are completely different. Load on each pair of wires is also different.

My 2031P arrived and are being run in. After a few months they will be converted to bi-wireable or maybe just actively crossed over !!
 
Another scientific:p way to put it :
mmmhh, maybe John Kreskowsky had already illustrated it in his graph,but
I would stress the concept of the added resistance introduced by cables,and
how it is usually counted when considering the global behavior of a cab, as it alters the Qts . So it would be interesting to put the lowpass circuit in the vicinity of the amplifier, and count the Ra of the cable together with coil's resistance( or coils- depends on the filter type).
Regarding the treble range, different geometry of the cable brings also some
changement : if the wires are kept parallel ----oh, well, that's the classic cable :p or free in space, disjunted ,the latter brings some confusion in treble resolution.
 
There are also some nonlinear effects as well that come into play:
Each driver is a non-linear load causing harmonics in its driving voltage due to the cable resistance (i.E. it is forming a non-linear voltage divider consisting of nonlinear driver impedance and linear cable resistance).
If each way has its own cable the coupling is reduced and therefore less of this source-induced distortion is coupled to the other way.
I don't know to what degree it is relevant. The effects must be quite sublime.

Regards

Charles
 
When bi-wired you still need the crossover unless you have an active crossover.

The high frequency driver must only be driven by high frequencies. Any low frequency signals will burn out the tweeter.

High frequency signals to the low frequency driver shouldn't harm it but may cause distortion.

Bi-Amping allows each driver to be driven by its own signal source. In a standard passive crossover situation (ie bi-wired) each amp would not be affected by the effects of the other drivers crossover. A simply bi-wired (ie single amp) to a speaker just places the point at which the effects of each driver are much closer to the signal source.Theoretically this reduces the interaction of the two drivers.

To get the best out of a bi-wired speaker you really need to bi-wire, bi-amp and drive the amplifier pair from an active crossover.
 
One way to look at the effect is with a car battery and a few lamps.

If you connect the lamps together and then connect them to the battery, if you insert a higher current bulb all of the lower wattage bulbs will dim.

If you connect each lamp separately to the battery they wont. Assuming that the battery is good and that it is fully charged of course.
 
I had a EE explain it to me once (there are two in my family). But I dont remember his explanation well enough to pass it on. I can say that with my speakers, bi wiring has a notable effect. From what I remember, its not the crossover that accounts for this difference, it has something to do with fields generated by different frequencies over long stretches of wire. The couple inches within the amplifier, that wire just required to get to the output terminals wasnt sufficiently long to make any difference, but over 8 or 10 ft it does.

A reasonably good accounting of what happens.

jn
 
One way to look at the effect is with a car battery and a few lamps.

If you connect the lamps together and then connect them to the battery, if you insert a higher current bulb all of the lower wattage bulbs will dim.

If you connect each lamp separately to the battery they wont. Assuming that the battery is good and that it is fully charged of course.

Unsuitable analogy IMO for two reasons:
1. It describes a DC circuit. Something we try to avoid like the plague in audio.

2. The lamps are in a series circuit. Not something we generally do with crossovers as we try to avoid having the bass signal run through the tweeter before it reaches the bass or vice versa.
 
I had a EE explain it to me once (there are two in my family). But I dont remember his explanation well enough to pass it on. I can say that with my speakers, bi wiring has a notable effect. From what I remember, its not the crossover that accounts for this difference, it has something to do with fields generated by different frequencies over long stretches of wire. The couple inches within the amplifier, that wire just required to get to the output terminals wasnt sufficiently long to make any difference, but over 8 or 10 ft it does.

The fields created by in the cable by the current running through it is cancelled by the current running in the opposite direction on its way back to the amp.
 
Close enough unless you split your cable along all or most of its length.
The inductance of a pair of cylindrical conductors that are spaced zero distance without contact is about 150 nH per foot. (edit:whoops, 120 nH per foot...sorry)

The capacitance will be dependent on the dielectric permittivity. It is non-zero.

There will be fields.

jn
 

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bi-wiring B&W N803s

Hi Cal,
My B&W N803s each have 4 binding posts, which lead me to believe each speaker has an LF filter for the woofers and a HF xover, for the mid range to tweeter. If, in fact, the LF filter and HF xover are connected to each other why are jumpers needed? Conversely, if they are not connected to each other, why wouldn't bi-wiring be of some benefit? What am I not understanding?

Thanks,
henrylrjr
 
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