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Science on Bi-wire

post #1 of 105
5/2/12 at 9:08am
Thread Starter 
I recently purchased a pair of B&W CM8's as my front L/R to replace a set of Vienna Acoustics Haydn's. I got the B&Ws at Magnolia. When I was trying them out they were trying to demonstrate the bi-wire difference, with and without. I could tell the difference between these CM8's and the other speakers they have there, including the cheaper B&Ws but I could not tell any difference with bi-wiring.

I have since researched bi-wiring and can't believe it is believed to improve sound. It does double the gauge thickness which could make a difference if using crappy wire. But it is the SAME wire connecting to the two sets of posts on speaker since the other ends are connected together on the AMP, it is basically the same thing as taking one speaker wire and connecting the amp in the middle of it with the two ends connected to the speaker. I can appreciate that people may believe they hear a difference but I am at a loss as to any scientific explanation. I have yet to find any link that goes into the science of it with any kind of analysis. Does anyone have any links they can share? I am not looking for "opinions" that it works, I want to see formulas, graphs, spectral analysis, whatever, that demonstrates some benefit, at least on paper.

Setup
Marantz AV7005
B&K Reference 7250
Onkyo 282
B&W Rosenut CM8 FL/FR
Vienna Acoustics Rosewood Maestro Center
Vienna Acoustics Rosewood Haydn SL/SR
Infinity ERS 310 in ceiling SBL/SBR
PS3
DirecTV Super DVR
AppleTV
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post #2 of 105
5/2/12 at 9:16am
Welcome to AVS

This has been covered numerous times on here. Use the forum search feature - there's plenty of info out there.
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post #3 of 105
5/2/12 at 10:13am
Quote:
Originally Posted by ntesla01 View Post

I recently purchased a pair of B&W CM8's as my front L/R to replace a set of Vienna Acoustics Haydn's. I got the B&Ws at Magnolia. When I was trying them out they were trying to demonstrate the bi-wire difference, with and without. I could tell the difference between these CM8's and the other speakers they have there, including the cheaper B&Ws but I could not tell any difference with bi-wiring.

I have since researched bi-wiring and can't believe it is believed to improve sound. It does double the gauge thickness which could make a difference if using crappy wire. But it is the SAME wire connecting to the two sets of posts on speaker since the other ends are connected together on the AMP, it is basically the same thing as taking one speaker wire and connecting the amp in the middle of it with the two ends connected to the speaker. I can appreciate that people may believe they hear a difference but I am at a loss as to any scientific explanation. I have yet to find any link that goes into the science of it with any kind of analysis. Does anyone have any links they can share? I am not looking for "opinions" that it works, I want to see formulas, graphs, spectral analysis, whatever, that demonstrates some benefit, at least on paper.

Setup
Marantz AV7005
B&K Reference 7250
Onkyo 282
B&W Rosenut CM8 FL/FR
Vienna Acoustics Rosewood Maestro Center
Vienna Acoustics Rosewood Haydn SL/SR
Infinity ERS 310 in ceiling SBL/SBR
PS3
DirecTV Super DVR
AppleTV

I think you already have your answer.

Good luck finding any solid science showing an audible improvement.
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post #4 of 105
5/2/12 at 10:25am
I have my theory that if you buy good speakers with good crossovers, why would you even consider bi wiring?
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post #5 of 105
5/2/12 at 11:43am
From the questions I've seen posted on forums, it looks like a bi-wire speaker creates more problems than it solves. Many people do not connect the terminals and lose either the high or low.

I don't know if you've seen this article, but it does explain some of the "supposed" benefits and science behind it. The article implies separate crossovers within the speaker assembly, hence each speaker is only drawing the high or low signal (????).

http://www.brilliancehifi.co.uk/how-...e-speakers.htm
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post #6 of 105
5/2/12 at 12:09pm
I think the best approach is to come to an agreement. Anything related to "bi" in these forums should be handled with a "Don't Ask, Don't Tell" policy.

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post #7 of 105
5/2/12 at 1:32pm
Quote:
Originally Posted by bizwiz41 View Post


I don't know if you've seen this article, but it does explain some of the "supposed" benefits and science behind it.

Pure unadulterated hogwash. The claimed benefits would only be realized if the passive crossover was located at the amplifier end of the wires, with filtered signals being sent from there to the drivers via separate wires. Even then the effect would be slight.
The trouble with their explanation is that it's all couched in pseudo-scientific 'theory', with no hard fast measured results to back it up. Since it's such a simple affair to measure the results both ways the lack of measured results means only one thing, that the proponents don't want measured results to be known. And don't think for a moment it's a coincidence that the most fervent proponents of bi-wiring are the manufacturers of high priced wire, the masters of hogwash.
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post #8 of 105
5/2/12 at 1:52pm
Quote:
Originally Posted by Bill Fitzmaurice View Post

Pure unadulterated hogwash. The claimed benefits would only be realized if the passive crossover was located at the amplifier end of the wires, with filtered signals being sent from there to the drivers via separate wires. Even then the effect would be slight.
The trouble with their explanation is that it's all couched in pseudo-scientific 'theory', with no hard fast measured results to back it up. Since it's such a simple affair to measure the results both ways the lack of measured results means only one thing, that the proponents don't want measured results to be known. And don't think for a moment it's a coincidence that the most fervent proponents of bi-wiring are the manufacturers of high priced wire, the masters of hogwash.

I just don't understand. What on earth would the sellers of expensive wire have to gain by selling people twice as much of it?






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post #9 of 105
5/2/12 at 2:56pm
Quote:
Originally Posted by Bill Fitzmaurice View Post

Pure unadulterated hogwash. The claimed benefits would only be realized if the passive crossover was located at the amplifier end of the wires, with filtered signals being sent from there to the drivers via separate wires.

Err... no. Electricity works off demand. The HF side of the crossover blocks the LF side, so only the current for the HF driver will flow in the cable going to it and vice versa. This isn't about signal voltage.

Some reading....

http://www.geocities.ws/jonrisch/biwiring.htm

http://www.geocities.ws/jonrisch/page8.htm
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post #10 of 105
5/2/12 at 3:31pm
Quote:
Originally Posted by kiwi2 View Post

Err... no. Electricity works off demand. The HF side of the crossover blocks the LF side, so only the current for the HF driver will flow in the cable going to it and vice versa. This isn't about signal voltage.

Some reading....

http://www.geocities.ws/jonrisch/biwiring.htm

http://www.geocities.ws/jonrisch/page8.htm

You won't gain any points by posting links to Jon, the Patron Saint of the Wire Mountebanks. The mere mention of the phrase 'double blind test' will get you permanently banned from his accurately named Audio Asylum cables forum.
Jon is long on hype, completely lacking on proof.
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post #11 of 105
5/2/12 at 3:42pm
Quote:
Originally Posted by Bill Fitzmaurice View Post

You won't gain any points by posting links to Jon, the Patron Saint of the Wire Mountebanks. The mere mention of the phrase 'double blind test' will get you permanently banned from his accurately named Audio Asylum cables forum.
Jon is long on hype, completely lacking on proof.

Nevertheless you do not need crossovers in front of the speaker cables to achieve HF/LF current follow separation. Crossovers upstream of the cables does the same thing.
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post #12 of 105
5/2/12 at 4:49pm
Quote:
Originally Posted by kiwi2 View Post

Nevertheless you do not need crossovers in front of the speaker cables to achieve HF/LF current follow separation. Crossovers upstream of the cables does the same thing.

Whatever. Show us the measured test results and/or DBT results that prove bi-wiring is audibly better.
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post #13 of 105
5/2/12 at 5:57pm
The only advantages I would see are when you assign more power to the speaker via bi wire. My Yamaha receiver can assign 2 channels of the 7.1 to bi wire. This is done in the settings and improves the sound of the fronts only because I have increased to power to them.
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post #14 of 105
5/2/12 at 6:34pm
Quote:
Originally Posted by mo95c View Post

The only advantages I would see are when you assign more power to the speaker via bi wire. My Yamaha receiver can assign 2 channels of the 7.1 to bi wire. This is done in the settings and improves the sound of the fronts only because I have increased to power to them.

But that would technically be bi-amping, as you are dedicating one full amplifier channel to each of the two lines.
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post #15 of 105
5/2/12 at 7:01pm
True. I guess I jumped the gun with my post. I see a purpose for bi amping but no difference with bi wiring
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post #16 of 105
5/2/12 at 7:54pm
Maybe I'm off, but I would worry that bi amping would be a greater risk of exposing amps which were not perfectly balanced. I guess it would be equivalent to unintentional tone control.
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post #17 of 105
5/3/12 at 2:56am
Quote:
Originally Posted by txmxer View Post

Maybe I'm off, but I would worry that bi amping would be a greater risk of exposing amps which were not perfectly balanced. I guess it would be equivalent to unintentional tone control.

If someone (properly) biamps, they'd have an active crossover ahead of their amps. I can take virtually any amp and level match them inside my active crossover.

I've mated a 1v input sensativity dbx BX1 monster solid state amp to a Viva 300B SET amp for my HF inputs. I don't recall the input sensativity of the 300B, but I was able to match them perfectly and it sounded great (as long as I stayed within the limits of the 300B)

Matching amps & (properly) biamping = not a problem
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post #18 of 105
5/3/12 at 2:58am
I might add... (if I recall the formula correctly)

You simply take "20*(log v1/v2)" where v1 and v2 are the input sensativities of each amp. This formula will give you a value and that number represents the number of db's you want to decrease the more sensative amp. Once you do that, viola, they are level matched.
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post #19 of 105
5/3/12 at 5:21am
Quote:
Originally Posted by coytee View Post

Once you do that, viola, they are level matched.

voilÃ*
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post #20 of 105
5/3/12 at 5:47am
Quote:
Originally Posted by coytee View Post

I might add... (if I recall the formula correctly)

You simply take "20*(log v1/v2)" where v1 and v2 are the input sensativities of each amp. This formula will give you a value and that number represents the number of db's you want to decrease the more sensative amp. Once you do that, viola, they are level matched.

Or you can just trim the volume controls on the crossover for each passband until it sounds good.
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post #21 of 105
5/3/12 at 6:08am
Bi-amping still seems really silly, especially for those that buy expensive speakers.

You've got this whiz kid that designs and carefully selects the components that go into a speaker circuit to perform in a very exact way.

Then someone installs said speaker by disconnecting the crossover and bi-amping the speaker, completely defeating the designers efforts.

Then you have to go back and level match and put in your own active or passive crossover.

But, do you have anywhere near the knowledge or tools to design a crossover as effectively as the speaker designer? I'm guessing not. If you did, wouldn't you be designing and selling speakers?

Just my thoughts.
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post #22 of 105
5/3/12 at 6:09am
Quote:
Originally Posted by Bill Fitzmaurice View Post

Or you can just trim the volume controls on the crossover for each passband until it sounds good.

why would you buy speakers that didn't sound good with the provided crossover?
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post #23 of 105
5/3/12 at 6:17am
He wouldn't. He'd build 'em.
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post #24 of 105
5/3/12 at 6:23am
Quote:
Originally Posted by psgcdn View Post

He wouldn't. He'd build 'em.

why would he build speakers with a poor performing crossover?

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post #25 of 105
5/3/12 at 6:25am
Quote:
Originally Posted by txmxer View Post

Bi-amping still seems really silly, especially for those that buy expensive speakers.

You've got this whiz kid that designs and carefully selects the components that go into a speaker circuit to perform in a very exact way.

Then someone installs said speaker by disconnecting the crossover and bi-amping the speaker, completely defeating the designers efforts.

Then you have to go back and level match and put in your own active or passive crossover.

The fact of the matter is that the very finest passive crossovers available are still far from perfect. From the standpoint of insertion loss alone active does work better, and you can't instantly dial up any slope, corner frequency or Q value you wish with a passive. That doesn't mean that you don't need a minimum skill set to successfully implement an active crossover, but it's not rocket science either. OTOH designing high quality passives is pretty close, so most speakers used by average listeners with average budgets don't have sophisticated crossovers. If one wants to significantly improve the sound of an average speaker, and has the knowledge of how to implement an active system, it can give much more bang for the buck than investing in a more expensive passive system.
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post #26 of 105
5/3/12 at 6:41am
Quote:
Originally Posted by Bill Fitzmaurice View Post

The fact of the matter is that the very finest passive crossovers available are still far from perfect. From the standpoint of insertion loss alone active does work better, and you can't instantly dial up any slope, corner frequency or Q value you wish with a passive. That doesn't mean that you don't need a minimum skill set to successfully implement an active crossover, but it's not rocket science either. OTOH designing high quality passives is pretty close, so most speakers used by average listeners with average budgets don't have sophisticated crossovers. If one wants to significantly improve the sound of an average speaker, and has the knowledge of how to implement an active system, it can give much more bang for the buck than investing in a more expensive passive system.

If I recall, you design equipment? Speakers? I was thinking I read that somewhere?

I understand what you are saying, but I think there are a good many 'philes that put in equipment without anything other than golden ears to tell them how effective their efforts have been. Then there is the specific selection of the various drivers. If you were designing a system with the notion of an active crossover I would think you might approach the entire speaker cabinet and driver selection differently. Just thinking "out loud", let me know if you see it differently.
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post #27 of 105
5/3/12 at 7:41am
That's a pretty damned big IF, Bill. As far as insertion losses with a passive, don't you think that's rather dwarfed by the inefficiency of drivers, after all it's not like they take all the power you give them and turn it into sound. From my way of thinking, if I want to improve the sound of an average speaker, I'd opt for getting a better speaker instead of wasting (IMO) my time, which has to be worth something, into sinking monies into a measuring system, electronic crossover components, then trying to improve on the transfer function of the passive crossover. When something screws up in the electronic crossover a couple of years down the road, and it will, what do I do then? In the end, I've still got an average speaker with average drivers in an averagely braced box that looks...well, average.
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post #28 of 105
5/3/12 at 8:51am
Quote:
Originally Posted by txmxer View Post

If you were designing a system with the notion of an active crossover I would think you might approach the entire speaker cabinet and driver selection differently.

I choose them exactly the same way.
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post #29 of 105
5/3/12 at 11:38am
Thread Starter 
The thing that does not seem to hold up in bi-wiring is the theory that the electrical properties on one side of a wire might be different than the other. Voltage and other properties will equalize themselves across the wire at or near the speed of light much faster than an ear can hear. The wire = all electrically conducting parts that are touching. So my bi-wire clips I have installed so I don't have to bi-wire are part of the wire. Two speaker wire runs from the same amp terminal is also the same wire, the amp is just in the middle of it now. So whatever is supposedly bleeding out of the woofers and messing up the mid, tweeters or vice-versa is going to happen with bi-wiring just like it would without.

One disappointing thing is that B&W and high-end manufactures are catering to this by putting in bi-wire connections. Is that because they are in-league with cable manufacturers? I notice I did not get any specs from B&W about how bi-wiring would change response, just a "it may ...."

I agree bi-amp does not make sense. Why would I spend this money on the CM8, getting both quality components AND the engineering that went into, and then immediately try to remove the engineering. I imagine bi-amp would work if you could buy a "box of speakers", no cross-overs, just a box with speakers and ports mounted in it with connections directly to the speakers. Then you could amp each speaker individually with a multi-amp and control the crossovers in software.
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post #30 of 105
5/3/12 at 12:40pm
There are some speakers that were designed to be bi-wired, like my Vandersteens. I still don't see how it's any different than using two wires from the amp vs one with a jumper between the two binding post sets, except for the obvious change in wire gauge you get by doubling up. I think there was some BS about using different wires for the woofer vs the mid/tweeter to take advantage of some wires being better for low vs high frequencies, but I think most of us now think anything other than adequate gauge and reasonable quality is just marketing.
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