Biwiring, why?

[Cpt.Issues]

I read an article once about biwiring..

Essentially aside from a minor change in impedance by having two low-resistance connectors in parallel there any isolation introduced by biwiring?

The article raised an good point - 'electrons do not readily separate into those participating in high and low frequency signals because this is the choice of paths for them'.

So why biwire? In your collective experiance does it make any perceptible difference?

 

[plastic penguin]

No.

 

[Dan Turner]

The article raised an good point - 'electrons do not readily separate into those participating in high and low frequency signals because this is the choice of paths for them'.

Actually they do. Remember that the electicity isn't just flowing from the amp to the speakers, it's a circuit with the electrons flowing from the negative loudspeaker terminal on the amplifier to the speaker, through the cross-over to the speaker cones and back though to the amplifier's positive teminal. With the cross-over split, one part of it filters out high frequency signal (e.g. prevents the electrons which comprise the high frequency signal from completing their circuit) and the other filters out the low frequency signal (e.g. prevents the electrons which comprise the low frequency signal from completing their circuit). Hence only electrons at the frequencies that are allowed to pass through each respective part of the cross-over actually complete the circuit.

Having said all that I'm not an advocate of bi-wiring. I've found that spending the whole budget on a better singel-wire speaker cable to be much more beneficial. I'm sure it depends on amp, cable, speaker and personal taste in any given situation though.

 

[the record spot]

I gave up on it; went back to single wired with cheap multistrand copper cable. No major detraction in sound quality, though I dare say if I were a manufacturer of biwire cables, I'd be sure to point out the many benefits.

 

[Overdose]

Actually they do. Remember that the electicity isn't just flowing from the amp to the speakers, it's a circuit with the electrons flowing from the negative loudspeaker terminal on the amplifier to the speaker, through the cross-over to the speaker cones and back though to the amplifier's positive teminal. With the cross-over split, one part of it filters out high frequency signal (e.g. prevents the electrons which comprise the high frequency signal from completing their circuit) and the other filters out the low frequency signal (e.g. prevents the electrons which comprise the low frequency signal from completing their circuit). Hence only electrons at the frequencies that are allowed to pass through each respective part of the cross-over actually complete the circuit.

This is incorrect, as all 'electrons' complete the circuit, as their source and return is still only one channel of a stereo amplifier. The component parts of the signal simply travel down different conductors and this results in the same interaction with the amplifier. Bi-amplification on the other hand, is entirely different, as each part of the crossover is fed by its own independent amplifier, although this still is not the best solution.

 

[Overdose]

Forgot to add that I did try it, but the only noticeable differences were less money in my pocket and more cable to have to tidy.

 

[Cpt.Issues]

Bi-amping I can understand would make a difference. With bi-wiring I can't help but notice it my bi-wire cable all terminates in the same plug..

I just wondered if there was any independant evidence for it making a difference?

 

[Anonymous]

Bi-wiring just changes the electrical properties of the overall cable. It simply becomes a thicker cable. It "may" make a tiny difference, but if you bi-wire, then put the terminal jumpers back it doesn't change one jot. (Try it).

Of course, don't try that with a bi-amped system as you might blow something up.

 

[Gusboll]

I never noticed a huge difference when I switched from bi-wire to single. When I changed to bi-amp though; difference; and for the better.

 

[BenLaw]

I just wondered if there was any independant evidence for it making a difference?

No.

 

[Anonymous]

It should not make much difference... Biwiring with two distinct sets of wires from a single amplifier with A+B zone does make a difference, though I would not say it improves anything. Tried it with Yamaha AS-500 and MA BX5 and found that some of the harshness was gone, but some of the clarity went with it. Low frequencies were especially muddier, yet not dramatically. But solving a problem by creating another is no solution. Same improvement of the harshness was achieved using better single wires and warmer CD player - like Arcam CD-17. Tried the wires and the CD Player separatly, then together, and there was an improvement at each step. But that way it did not mess with low frequencies.

Did not experiment largely, though... but even logically, I don't see much why splitting the signal to the wires instead of the crossover bridge of the speaker is to make a difference...

 

[AlmaataKZ]

bi wiring does not make any difference and is a waist of time and money.

 

[Mooly]

I read an article once about biwiring..

Essentially aside from a minor change in impedance by having two low-resistance connectors in parallel there any isolation introduced by biwiring?

The article raised an good point - 'electrons do not readily separate into those participating in high and low frequency signals because this is the choice of paths for them'.

So why biwire? In your collective experiance does it make any perceptible difference?

Let's try and make this easier to understand.

1. The speaker terminal/s on the back of an amplifier are, for a typical modern solid state design, essentially considered a "constant voltage source". That means that the audio voltage present is unaffected by the varying load or impedance of the speaker.

Remember, the impedance of a speaker varies enourmously depending on the frequency. This means that the speaker "draws" more current at specific parts of its frequency range than others. The impedance could vary from as low as 3 ohms to as high as 30 ohms over the audio band.

It is the bass driver that exibits the highest current draw (and presents the lowest impedance)

Familiar with ohms law ?

Your speaker lead has an essentially constant resistance at all audio frequencies and beyond.

Your speaker leads "lose" or "drop" some voltage across their length as speaker current flows. The important point is that this voltage drop is not linear because the speaker presents a varying "load" or "impedance" depending on the frequency.

This means that the voltage at the speaker terminals is not a true image of what appears at the amplifier output.

To make this easier to understand imagine a test CD with a frequency sweep from 20 to 20khz and that the amplifier volume control is turned to give say 10 volts rms at the amp output. If the speaker were "just a resistance" of say 8 ohms then the voltage at the speaker would be 10 volts less the voltage lost across the leads due to their resistance. The voltage at the speaker might therefore be only 9 volts but it would be constant with frequency. The only audible effect would be a theoretical reduction in sound level. A real speaker though is anything but a constant resistance, it is a resistance that varies with frequency. So the measured voltage at the speaker now varies depending on frequency of the applied signal and consequent current drawn. That modifies the sound from the speaker. The output of the speaker now depends on frequency to some extent. The big question is whether that is audible or objectionable. For long leads of high resistance (thin wire) it may well be. For short runs of thick cable probably not.

Bi wiring splits the HF and LF signal feeds such that the bass driver of the speaker still draws its large and varying current but now the hf and mid drivers (which draw far far less current) are fed via a separate feed from our "essentially constant voltage" source... our amplifier. So now the critical hf and mid drivers see the accurate voltage present at the amplifier terminals, while the bass driver (which from an audible view is considered less critical) gets a more distorted voltage due to it altering or "modulating" it's own drive voltage.

It is for you by listening to determine whether the change to bi wiring results in a different or better or worse sound.

 

[Inter_Voice]

From my persoanl experience I did not hear any improvement in SQ at all after bi-wiring and I have gone back to single wire using the same money for a better quality speaker cable.

I can hear some minor changes in SQ when the metal jumper plate at the back of the speaker is changed to a good quality jumper cable (but by not much).

I think bi-amping is a different story as a lot of reviews stated that there are huge jump in soundstaging :?

 

[Anonymous]

Think the question answers itself, indeed why? Also I have read numerous speaker reviews over the years (not necessarily in WHF) which recommended avoiding bi wiring even when the speakers had bi wire terminals on them! And of course thicker cable runs result from bi wiring.

 

[atkins4725]

From personal experience I do hear a difference for the better. The only reason my system isn't bi-wired at the min is due to the cost of the speaker wire and it being so close to Xmas but there is a very noticeable improvement to the SQ with my system.

 

[Overdose]

I read an article once about biwiring..

1. The speaker terminal/s on the back of an amplifier are, for a typical modern solid state design, essentially considered a "constant voltage source". That means that the audio voltage present is unaffected by the varying load or impedance of the speaker.

Familiar with ohms law ?

Your speaker lead has an essentially constant resistance at all audio frequencies and beyond.

Bi wiring splits the HF and LF signal feeds such that the bass driver of the speaker still draws its large and varying current but now the hf and mid drivers (which draw far far less current) are fed via a separate feed from our "essentially constant voltage" source... our amplifier. So now the critical hf and mid drivers see the accurate voltage present at the amplifier terminals, while the bass driver (which from an audible view is considered less critical) gets a more distorted voltage due to it altering or "modulating" it's own drive voltage.

It is for you by listening to determine whether the change to bi wiring results in a different or better or worse sound.

Whilst the voltage drop across the drivers will vary, I do not see how the voltage will be different at the speaker inputs. The source is the same.

In a parallel circuit, the voltage across each of the components is the same, and the total current is the sum of the currents through each component, this total current and constant voltage will be the same with one single pair of wires or two.

 

[Mooly]

Whilst the voltage drop across the drivers will vary, I do not see how the voltage will be different at the speaker inputs. The source is the same.

In a parallel circuit, the voltage across each of the components is the same, and the total current is the sum of the currents through each component, this total current and constant voltage will be the same with one single pair of wires or two.

I think this is what you mean

You are saying that the single (non biwired) speaker will still see the same voltage at the bass/mid/treble drivers (or the same voltage presented to the crossover) no matter what the audio signal or the resistance of the wire.

The problem here, is that if a large amplitude bass signal occurs in the music and particularly at the point where the impedance curve of the speaker is low then the bass driver will draw more current. That bass signal is "modulating" the content of the whole audio signal as the current ebbs and flows. It is pulling the whole signal level down. The signal at the speaker terminals is different to the signal at the amp output. The difference depends on the audio content and appears as a loss across the speaker lead.

The signal at the amp output is (should be) constant. If the mid and hf units (which draw comparatively little current) are bi wired then they still see the full output of the amp. In audio terms the midrange is the most critical part of the spectrum.

The question is whether that modulating of the signal is audibe as it also modulates the drive to the mid and hf units.

Hope that makes sense.

 

[MajorFubar]

That ties in with my own limited experience of bi-wiring, where the main difference I perceive, placebic or not, is in the mid-range. But then again, I’ve had speakers which seem to ‘shout’ too much when bi-wired, and I’ve gone back to single.

I have never worried too much about the science of HiFi. If something I do improves the sound to my ears or perception, then I’ll go with it, irrespective of whether sciences says I must be wrong. Life’s too short to argue about the whys and wherefores. Too much music to enjoy in too little time

 

[Anonymous]

Whilst the voltage drop across the drivers will vary, I do not see how the voltage will be different at the speaker inputs. The source is the same.

In a parallel circuit, the voltage across each of the components is the same, and the total current is the sum of the currents through each component, this total current and constant voltage will be the same with one single pair of wires or two.

I think this is what you mean

You are saying that the single (non biwired) speaker will still see the same voltage at the bass/mid/treble drivers (or the same voltage presented to the crossover) no matter what the audio signal or the resistance of the wire.

The problem here, is that if a large amplitude bass signal occurs in the music and particularly at the point where the impedance curve of the speaker is low then the bass driver will draw more current. That bass signal is "modulating" the content of the whole audio signal as the current ebbs and flows. It is pulling the whole signal level down. The signal at the speaker terminals is different to the signal at the amp output. The difference depends on the audio content and appears as a loss across the speaker lead.

The signal at the amp output is (should be) constant. If the mid and hf units (which draw comparatively little current) are bi wired then they still see the full output of the amp. In audio terms the midrange is the most critical part of the spectrum.

The question is whether that modulating of the signal is audibe as it also modulates the drive to the mid and hf units.

Hope that makes sense.

I am afraid you are thinking in DC terms. The crossover in the speaker separates the LF, MF and HF (for a 3 way) signals. Its as if each band had its own separate connection. As cables have a linear resistance, the amount of LF current flowing and resultant voltage drop is invisible to the MF and HF drivers.

 

[Anonymous]

If you get the science right, then less time is needed faffing about, and more can be spent enjoying music

 

[Farmitou]

I've never been able to tell a noticable difference between biwired or not. The speaker cable itself makes a noticable difference however ( I noticed differece each upgrade (from £2m >> £12M >> £Silly M)), in my case for the better, it may just be a change to the sound so make sure the cable is to your liking and definatly test with your system. It's already been said that Bi amping improves the sound stage etc, so that's my next updrade before speakers. Interconnects seem to make less difference, as long as there good quality to begin with too.

So I'll stop rambling on... I'm in the no difference camp.

 

[Overdose]

The problem here, is that if a large amplitude bass signal occurs in the music and particularly at the point where the impedance curve of the speaker is low then the bass driver will draw more current. That bass signal is "modulating" the content of the whole audio signal as the current ebbs and flows. It is pulling the whole signal level down. The signal at the speaker terminals is different to the signal at the amp output. The difference depends on the audio content and appears as a loss across the speaker lead.

The question is whether that modulating of the signal is audibe as it also modulates the drive to the mid and hf units.

Hope that makes sense.

Yes it does, but the speed at which electricity moves from place to place effectively makes any modulation instantaeneous in its effect with the other drivers. This is still a parallel circuit and the common link to the source effectively makes the set up of biwiring identical to a single pair. The exception, of course, is if the conductors in the single pair of wires are not sufficiently large enough (cross sectional area) to provide a minimal impedance, but for arguments sake, I assumed conductors of sufficiently low impedance (0.03 ohms for 14 guage copper wire at 10 feet approx).

 

[Mooly]

You're not understanding the theory.

The drivers are a "parallel" circuit within the speaker enclosure. From the speaker to amp is a series circuit. The 3 drivers, the bass mid and hf all do see the same voltage instantaneously. Whatever appears at the speaker terminals appears at the drivers together.

That isn't the problem.

Lets try and explain it another way. Imagine you placed a 10 ohm (quite high) resistor IN SERIES with the normal NON Biwired speaker set up and you played music. Now imagine the musical content causes the bass speaker to draw more and more current. That varying current drastically alters the voltage seen by all three drivers.

The impedance of the speaker varies according to frequency

http://www.churchsoundcheck.com/imp1.html

To highlight the effect lets go more extreme ... we short out the bass driver completely. In other words we take its impedance down to zero ohms. That kills all audio to all three drivers (disregarding the effect of the crossover network which adds a very small impedance to the bass driver circuit) as all voltage is removed. The 10 ohm series resistor means the amp is happy and still producing exactly the same audio signal.

For bi wired, with another set of leads back to the amp, we find the mid and hf is totally unaffected by all this. Our current demanding bass speaker now has no effect on their output.

 

[Anonymous]

The exception, of course, is if the conductors in the single pair of wires are not sufficiently large enough (cross sectional area) to provide a minimal impedance, but for arguments sake, I assumed conductors of sufficiently low impedance (0.03 ohms for 14 guage copper wire at 10 feet approx).

You're confusing resistance with impedence. Large cross sectional area will reduce resistance, but speakers work on alternating current (AC) and its the impedence that matters - combination of resistance, inductance and capacitance. The cross sectional area wont necessarily change the impedence.