Has anyone ever bi-wired a stereo or theater system? To clarify, bi-wire using Monster Cable Z2 Bi-wire kit or similar product? I'm doing a theater install for a customer using a Marantz SR9200, Marantz DV8300, and Paradigm Studio 40s. This system will be used for both music and theater applications. Any feedback good or bad on bi-wiring is greatly appreciated.

Thanks.
Brian

This message was edited by BSWalker on 04/20/03 06:41.

Have listened to b-wired speaks but for critical stereo reproduction...have not b-wired for any installs...most towers / boxed we use have cross over designs that provide optimization needed...and then again most issues are regarding improper room acoutics that have not been addressed... tweek and play if b-wiring is something new...I prefer tubes and plastic....:}

I've done it before for a customer cause they had the equipment that would do it, and he wanted me too. I don't think I can say that I can tell any difference. It's not like the wire knows how to carry only certain frequencies until it goes throught the cross over anyway.
So what's the point really??

Well, in my living room I did it cause I used some 14/4 and didn't want to try and squish both conductors into the same holes, so I took out the bridge-clips and am bi-wiring my system.
Result: larger wire AWG.

Brent, the wire "doesn't know" which frequencies to carry, but, as in any single-pathway circuit, the current anywhere in the circuit is the same, both in magnitude and frequency.

Therefor, only the frequencies passed by the crossover (along with any passed by the crossover's by-pass components) will flow through the wires. That's what they "know" to conduct.

I, too, had a reel of 14-2 lying around, so I bi-wired my Def Tech's. (Tri-wired if you count the line-level sub inputs; I just changed from speaker-level to line-level sub feeds; still evaluating.)

Another reason: my Sunfires have dual outputs for most channels, labeled 'voltage source' and 'current source' . The difference? The 'current source' has a 1-ohm power resistor in series with the + output terminal.

The 'current source' output is supposed to reflect the higher-impedance source characteristics of a tube amp, which would include the lower damping factor, so it's more suited to the higher frequencies, as the 'voltage source' output is better for the lows.

Brent, et al, I hope I didn't insult anyone with this explanation. I realize you were addressing a question and wanted to simplify.

Larry
www.fineelectricco.com

Here's the point:

Wire does not know how to carry only certain frequencies. It is something else.

Aside: I sometimes use a telephone test set to check for audio in larger systems. A strange phenomenon is that you can get audio with a test set from ground to ground when you have separate wire runs from the same amp into volume controls close enough to one another to connect a test set.

Why? Because the wire has resistance, and there is a slight voltage drop along the length of the wire as current flows. Remembering Ohm's law, the more the current, the greater the voltage drop.

Okay, so there's voltage drop. So what? Well, the crossover in a speaker will separate the audio into different frequency ranges. And what is the crossover getting as a voltage? It is getting the voltage between the plus and the minus input of the speaker. NOT the voltage out of the amplifier. It is getting the voltage out of the amplifier minus or plus whatever happens in the speaker wire (and sometimes capacitance and inductance of the speaker wire affects amp performance, but that is another discussion).

Let's look at the signal going to the woofer, and make up some numbers for illustration. If the woofer is being fed 100 Hertz at 10 volts, and has 9 ohms impedance, and the speaker wire has a half ohm in the positive half of the wire and a half ohm in the negative, the total impedance will be ten ohms and there will be one amp of current.

Because there is one amp and a half ohm in the ground lead, the "ground" terminal of the speaker goes from zero volts to one half volt as the woofer signal goes from zero volts to ten volts. The positive lead will vary from zero volts to 9.5 volts as the woofer signal varies (it is not really so simple because of sine waves, I do not mention polarity, and such, but that does not affect what I am trying to describe).

Okay, now let's send a high frequency along this wire. What we want to do is send the high frequency into the crossover and have it routed to the right drivers. That will happen. But if we send, say, two volts of high frequency, which will give us 200 milliamps of current, when we look at the signal going into the crossover, we will see that the two volts are coming from speaker input terminals that are wiggling around, because of the 10 volt 100 Hz signal, between 0 and 0.5 or 0 and 9.5 volts, 100 times per second! (okay, 200 times).

In other words, the actual voltage being fed to the high frequency portion of the crossover can vary by as much as a volt (in this case) as a result of the woofer signal's higher current flow! The two volts of high frequency are simply not going to get to the crossover without that 100 Hz signal changing it some. The high frequency signal will be modulated by the 100 Hz signal.

But after it goes through the crossover, you can't detect any 100 Hz signal, right? Well, have you talked on the phone recently with a man who has a low-pitched voice? The fundamental frequency of his voice did not make it through the lousy audio response of the phone system, but somehow your brain picked up the concept that he has a low voice. hmmm, it was not there but you heard it because it affected the high frequencies that got through....

what I wonder is, why do speakers that are not biwired, especially with long leads with as much as a couple of ohms, come out being listenable at all?

If you biwire, the higher frequency signals are not influenced by the lower frequency signals. And it is not the frequency, but the fact that the low frequency signals have so much more current, that can degrade the high frequency's clarity.

Try some extended listening with biwiring. You obviously can't do instant A-B tests, but you can live with your speakers the supposed better way, biwired, and then go back to non-biwired and see if you lose anything. I think you will (and I am one who is just driven crazy by fancy speaker wire claims!!!).

Ernie

Thank you for your responses. Ernie, your explanation on the electrical level makes sense. Thanks everyone for your time and input.

Brian

Thanks Ernie, that was the best explanation I have seen on Bi-Wiring.
Most of the differences I have perceived have been on dedicated audio systems , not that theaters wouldn't also benefit.
I had some Magnepan planar speakers which had external crossover jumpers in place. I originally had them wired conventionally(2 conductor) then tried Bi-Wiring them with 14g wire to my HK high current amp. The A speaker jacks directly to the woofer section and the B speaker jacks to the high frequency crossover and driver. I was concerned about the possible volume difference between the sections. As it turned out, the levels were perfectly matched.The soundstage was much better defined. The impact was a little stronger too. The difference was noticable, although maybe not to the average listener. Sometimes you have to listen for specific passages of music or instruments closely.
I have also tried the Bi-Wiring with some MB Quart speakers(home) and Onkyo and Yamaha receivers without much noticable difference. So go ahead and experiment!
You may want to listen for the soundstage with lots of different instruments. You may also want to experiment with your speaker placement too. This is an area often offering much improvement/differences in sound.

All ernie's explanations are true. For me bi-wiring at even short distances has shown a big diffrences. Providing the speakers are of high enough quality.Another thing it does is improves dampening factor. ( and amplifiers ability to control unwanted speaker cone movement ). When going from standard 12/2 to bi-wired 12/2 on my own Snell D's. I saw huge improvement in bass preformance. Any muddy bass tightened up a great deal.. My 2 cents bi-wire when and if possible providing the speakers support it..

Anyone that can hear the difference between biwired and non biwired speakers - I have some farmland to sell you in Florida. It certainly does no harm and if it makes you feel good, go for it. Ernie's post is full of misconceptions, but I've spent too much time writing about this issue in the past and am simply going to offer a few links of interest.

A tremendous amount of research has been done by reputable experts (and by reputable I DON'T mean Monster Cable and other snake oil vendors) on speaker cable related issues and the results are always the same. As long as reasonably good cable is used, people CAN'T hear the difference. Biwiring falls within that category.

[Link: 2eyespy.tripod.com]
[Link: verber.com]

p.s. Everyone that claims to hear the difference can NEVER hear the difference in a double blind test.


This message was edited by QQQ on 04/19/03 17:15.

Honest, guys, I never have heard of "biwiring" as running separate wires from the same amp to one set of speakers.

Effective bi-wiring would usually include bi-amplifiying. At the source, the preamp would feed output to an electronic (not passive, as in a speaker system) crossover, which has a high and low output. An audio nut would feed the low output to a Hafler 500 or some mondo amplifier of choice to feed the bottom end (frequency selectable, perhaps 100 to 500 Hz) and drive a subwoofer system. The high output would feed a pair of tube type McIntosh MC60s or the like which might drive some Magnepans or some speaker known for smooth mids and highs.

You will hear a difference with a system like that, but of course all the components are kind of tweeky to get a different sound.

Bi-wiring without bi-amplifying amounts to doubling the wire size. That never hurts.

=Tom

So, according to the bi-wiring analysis in QQQ's link, the "bi-wiring provides no advantage" theory is based on the assumption that the wire provides no appreciable impedance.

We agree that the only possible difference that bi-wiring can make is the elimination of the voltage-drop-induced 'modulation' one section imposes on the other, caused by the wire's impedance.

The conclusion: if the wire has impedance, then bi-wiring can make a difference; if not, then there's no advantage. So, either bi-wire, or use heavier wire. I guess I bi-wired for the right reasons: I had plenty of the 14 ga., and didn't need to buy 12 ga.

That, and Sunfire's recommendation for bi-wiring with the tweeters on the 'current-source' terminals and woofers on the 'voltage-source' terminals. If ya' got 'em, use 'em.

Larry
www.fineelectricco.com

Larry said We agree that the only possible difference that bi-wiring can make is the elimination of the voltage-drop-induced 'modulation' one section imposes on the other, caused by the wire's impedance.

This is the common misconception that people use to justify "buy-wire". A wire cannot modulate one signal onto an other as long as the wire behaves as a linear system. The ability of a wire or any other linear element to modulate a signal goes against any signal analysis method proven to work in a lab and by theory. Instead of reading false information on the web try taking a first year level electrical engineering course in signal analysis.

At the end of the day, electrical theory, laws of physics etc mean nothing. The only test that counts is that performed by the imperfect audio receptor that is the human ear. Everyones hearing is different, and peoples idea of whether a perceptible change in sound is an improvement or not, is subjective.

BSWalker - try it out for your client, if they think its an improvement it should be an easy sell.

Personally, I've got an old pair of Polk Audio LS70 speakers. Bass was loose and boomy until I bi-wired/amped them. The improvement was very noticable, not just to me but also to my sceptical wife.

I will happy demonstrate the difference to clients, and always say to them that no matter what upgrades they are considering, its wasted money if they can't hear the difference themselves!

Excellent...bravo...best discussion on b-wiring I have read from tweekers...thank u all...just remember the bottom line always being audio performance....room acoutics are typically the largest problem we have to deal with ...my 1 cent

sarcasm* Ya, science is just a bunch of bunk. *sarcasm
There have been numerous scientific studies performed and EVERY, EVERY single time the results are the same. People CANNOT hear the differences between reasonably decent cables. You can talk about the differences until you are blue in the face, but the moment you have to do the test blind, you have NO idea what you are listening to.

There have even been large awards ($10,000 +) offered on numerous occaisons to anyone that can hear the differences in a double blind test. No one EVER collects the award.

This message was edited by QQQ on 04/20/03 14:45.