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THE AM BULLETIN BOARD => Technical Forum => Topic started by: k4kyv on April 18, 2007, 05:57:18 PM

Title: Bi-Wiring
Post by: k4kyv on April 18, 2007, 05:57:18 PM

“Bi-wiring” is a controversial topic. Some people are quite certain it makes an audible difference. Some others are convinced that it can’t actually make any difference at all. The purpose of this analysis is to try and decide whether it is at least theoretically feasible that bi-wiring can make any difference.

it is sometimes claimed that separating the signals for the tweeter and woofer means they do not now ‘interfere’ in some manner which may arise when they share the same cable


Title: Re: Bi-Wiring
Post by: WBear2GCR on April 20, 2007, 07:53:19 PM
The "interference" idea is bunk, imho.

Otoh, what can and likely does happen is that by putting two identical cables in parallel the C that the amp sees from the cables is increased, the L is the same, and the R per driver is effectively slightly lower due to the reduction in peak current/bandwidth through a given cable.

Also, you have the opportunity to use a "thin" sounding cable on a given half and a "thick" sounding cable on the other "half" of the speaker. An example of that is a cable that is somewhat inductive vs. a cable that is somewhat capacitive - if you use only one cable or bi-wire with two cables of the same type there is less or no difference in the signals presented to a given section of the speaker (driver + xover in most cases). Whereas you could use a relatively inductive cable on the HF section to get a slightly less harsh or a smoother overall HF sound and a capacitive cable on the bottom to get a "faster" sound from the LF section. Other permuations are possible, of course.

AND, the effects in many cases may be subtle.

This is probably a reasonable explanation of the observed/heard phenomena...



Title: Re: Bi-Wiring
Post by: WA1GFZ on April 20, 2007, 09:03:29 PM
I want to start a business selling Speaker cable transmatches.....Imagine a pair of KW matchboxes on your speaker cables.

Title: Re: Bi-Wiring
Post by: W1GFH on April 20, 2007, 11:12:49 PM
I want to start a business selling Speaker cable transmatches.....Imagine a pair of KW matchboxes on your speaker cables.

Actually, that's not a horrible idea. You could market it to the audio crowd with the logic that in order to get optimum power transfer between the hifi amp and the speaker, you need to tune the speaker cable for a 1:1 "match".  ;D

a pair of KW matchboxes

Cheaper yet, strip down some MFJ tuners, repackage them in a stainless-steel chassis with teakwood knobs, and resell 'em for $15,000 each.

Title: Re: Bi-Wiring
Post by: k4kyv on April 21, 2007, 03:37:34 AM
Or follow the design of the Maxxcomm automatic antenna matcher.  Keep the stainless-steel chassis with teakwood knobs (attached to a couple of old rotary pots salvaged from a junked broadcast receiver and not connected to anything), mount some "high end" terminal connectors on the chassis and simply connect one set to the other with hook-up wire or zip cord. Cut up some old pieces of scrapped glass-epoxy computer mother board and place them inside the chassis, with the solder side showing, in such a manner as to hide the cheap pots and the connections between input and output terminals, and fill the whole thing with clear epoxy.

Write up a slick, top-quality-paper instruction manual with a bogus pseudo-technical explanation of reasons why matching the speaker cables to the amplifier improves the tessitura and results in stunningly brilliant highs, ultra-transparent lows, and increases the warmth of the sound. Mention that adjusting the "tuning controls" may make a very subtle improvement not immediately noticeable to the uneducated ear, and  may depend on the quality of the speaker cable, amplifier and speakers.

For best results, use two units for each stereo channel, one to match the amplifier to the speaker cable, and a second one to match the speaker cable to the speaker.

Offer a special package discount: "save $5000 by purchasing a matched set of four units for only $55,000".

Title: Re: Bi-Wiring
Post by: WBear2GCR on April 21, 2007, 10:19:11 AM
Actually there are some companies that make speaker cables with "boxes" on the ends!

Nominally, they are there to do "matching" in terms of impedance. In practice, imho, they don't work and make things sound worse in most situations.

Wrt this high-end stuff, it all seems silly until you start to get somewhat deeply into trying to get/build a system that is clean. As you go through it trying to eliminate, mediate or correct deficits or issues you find that the devil is in the details... it's a constant struggle that involves endless balancing and compromises.

The confounding factor is when something that you know for sure can not or should not make any difference at all does.

Until you experience it for yourself, it's really hard to imagine. I have, and it pisses me off when it happens.

There are Patented speaker cables that are designed to have a nominal "8 ohm" impedance. You can find at least one of them under the name John Dunlavy. Fyi.

But Don, I like ur approach to marketing! Can I hire you, dress you up in a fine Italian suit and have you make presentations??  ::)


Title: Re: Bi-Wiring
Post by: W1GFH on April 21, 2007, 02:16:32 PM
Or, like the "aliens" from ( PLAN 9 FROM OUTER SPACE, simply present trash and junked test equipment as advanced technology. (Is that a hiway contruction barrier light with a fishing bobber electrical-taped to it?)

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands