|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
In Reply to: Why Bi-wire? posted by markrohr on August 11, 2003 at 04:33:21:
Most amplifiers have some form of feedback implemented by sampling the output at or close to the speaker terminals. Amp works to keep the output voltage close to the original (or a multiple thereof).Bi-wiring avoids any interactions between currents (and attendant fields) of the high- and low-pass sections of the speaker because the two sections only meet at (or near) the place where the amp can exercise control over the signal. In other words, the only wiring common to woofer and tweeter is now inside the amp's feedback loop.
Single wiring allows currents flowing to and from the woofer (actually to the low-pass xover section) to modulate the signal presented to the high pass xover section because the cable has a non-zero impedance.
I'm still not convinced this is right, so I need to think about it some more....
Perhaps there is an analogy to good grounding techniques. I was taught to do the thought experiment of putting a small resistor in place of every ground connection in a piece of electronic equiment and looking at the ways in which things like capacitor charging currents can modulate ground voltages.
Follow Ups:
Been there, done that , made a chart.See:
http://www.geocities.com/jonrisch/biwiring2.htm
Jon Risch
.
The comments you made about the relationship between amplifier output Z, cable type and IM attenuation sound like a good model for predicting which combinations are likely to benefit from bi-wiring.
Obviously, the xover topology is also an important factor, since it will affect the accuracy of your simplified circuit for one driver driving the other, and the range of frequencies over which biwiring would reduce IM. I would imagine that the series impedance of most xovers sections around the xover point is somewhere near the impedance of the driver, which should be much higher than the cable and amp output impedance. Doesn't this reduce the potential benefit of biwiring?Peter
You are a hard man to convince, Peter. Now get it together for you to drop by for a short time, so that we can catch up on things. I promise not to make things into a time consuming situation, for your family's sake, if for no other reason.
This post is made possible by the generous support of people like you and our sponsors: