Dumb newbie question

[matthew2]

Im thinking of getting some RF-3's. I want to know more about bi-amp, bi-wire stuff. What is it, why is it better, how do you do it, and what do you need?

Thanks

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Matthew

[Colin]

try searching the forums and you will come up with hundreds of posts to read, the more stars on the posters name and the longer and more detialed the answer the better -

congrats on your new speakers - get the best speaker you can afford; that is where the music is ...

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Cornwalls & Klipsch subs; leather couch & feet up; lights out & tubes glowing!

[Mighty Favog]

Matt-

Do a search on this BB for "Bi-Wire" or "Bi-Amp". There is pretty much discussion on the two topics. For starters, anyway, it's not the same thing exactly. The explainations can be quite lengthy. William 'Gil' McDermott (on this BB) usually has some comprehensive rundowns of the possibilities with either.

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Tom

KLF-20 Mahogany (Cornell Hotwired)

McIntosh C33 Preamp

McIntosh MVP-841 CD/DVD

Rotel RB-1080 Amp

Yamaha PF-800 Turntable/ Sure V15 Type V Cartridge

Ortofon VMS-30 mkII Cartridge

Stanton 999SS Cartridge

Yamaha K-1020 Cassette

dbx 1231 EQ

H.H. Scott 830z Analyzer

Monster Interlink 400mk II

Monster Interlink 300mk II

Monster Video 2 (DVD to TV)

Monster Power HTS-5000

MIT Terminator 2 Bi-Wire Speaker cables (and I do mean CABLES)

Studio Tech U-48RW Cabinet

Enough empty boxes for a fire hazard!

[WMcD]

Boy, I don't know how my name got brought up in this context. Except that I'm long winded.

But just so you know what is the starting point, and where are we going, I'll set out some thoughts.

- - - - -

The standard set up is as follows for a given channel (left or right): You have one amplifier handling all frequencies. All the signal goes down one pair of wire. Then into the cross over network in the speaker.

We'll assume you have just a bass (woofer) and treble (tweeter) driver in the speaker. The cross over network divides the signal into the high and low frequencies and sents them to the appropriate driver. (We have multiple drivers because it is not possible to make one driver cover all the frequencies we hear.)

These are called passive networks. It is difficult to design an accurate passive network for various reasons, mostly a matter that the drivers do not have constant impedance. A lot of engineering time is devoted to this. Computerized analysis has improved the situation.

- - - - -

So what can we do to make it different in our beloved music systems? Is "hotrodding" possible with real improvement? Also, what is so bad with the set up above, in theory and practice?

I personally believe that the above system works just dandy. But others seek, and perhaps find, improvement. Let look at them from a technical standpoint.

But first, you'll note that I'm Janus. If a commercial seller makes a claim, I want proof. If a home amateur makes a claim, I'll take it with a grain of salt and back away because I'm not there to hear it. I think that is the most fair.

- - - - - -

1) "Better Speaker Wire". There is much speculation that plain old 18 or 16 gauge zip cord does not pass the signal to the speaker without distortion (and I include frequency response problems in that).

In the bad old days, retailers would give out hanks of 22 gauge wire (thin) or the like. This probably had shortcomings. 18 or 16 gauge (much thicker) was probably an improvement and this is what PWK suggested for use.

The solution suggested is to buy bigger, "better" wire, even fatter than 16 gauge. This is pretty much along the philosophy that if two or four steps bigger is better, then six or eight steps bigger give the same, progressive, level of improvement.

I don't buy this because I've never seen anyone publish a frequency response curve showing an improvement. (There are some oddball situations of difficult loads, unstable amps, where it might help, but these are rare.)

Some people say they hear a difference. Who am I to contradict them.

2) "Bi-wire". Again this is an issue about wire.

One theory says that high frequency signals and low frequency signals somehow interfer with each other in the wire. The solution is to run two pairs of wire to the speaker from the amp. Some speakers allow the user to remove a jumper and thus the individual sections of the crossover in the speaker still function to keep only the highs going to the tweeter, and the lows going to the woofer.

A related theory says that the feed wires can optimized for transmission of highs and lows in either path. So you have different types of wire in the bi-wiring scheme.

I don't buy this either. Plain old zip cord has good or excellent transmission characteristics at these frequencies. I've run the curves with an LMS system and don't find a difference from input to output. None the less, others report hearing a difference.

3) Bi-amping. Here there is a separate amp for the tweeter and the woofer. Naturally this requires bi-wiring.

In this scheme, there is an electronic or "active" cross over network as part of the amp, and usually the passive network in the speaker box is not needed. It is probably fair to say the proponents of this are not advocating multiple amps quite so much as the use of the active crossover.

There is good reason to believe this can give an improvement. The reason is that it is more easy to get exact results out of the active network. Of course it assumes that you're replacing a problematic passive cross over with a non problematic active one.

I can buy this. But there is that basic assumption there is problem with the passive cross over to begin with.

- - - - - -

I'd point out that the use of active passovers, bi- amping and bi-wiring is indeed used for subwoofers in HT. Naturally the scheme works well. It is part of the sophisticated "bass management" system.

- - - - - - -

My personal belief is that 1 and 2 might give some improvement, but very, very minimal. I'm puzzled that people report a difference. However, I can't question their perception or good faith. My thought is that perhaps the modifications solved some other unrecognized problem, like a bad connection. I've experienced such things.

- - - - -

We've seen that the Klipsch organization is now advertising that they use Monster brand wire internally in their speakers. We should all give a very close reading to the language. I do not see a clear claim that there an actual measurable improvement in frequency response.

If the engineering department in Indy or Hope will come up with some measurements, I'll be the first to take a very close look, buy new wire, and get out the soldering iron.

One must read carefully. My recall is that one earlier piece of advertising by the Klipsch organization (not PWK) said something like, "All critical high frequency connections are made with silver solder." They did not, actually, say silver solder made a difference.

- - - - - - -

Believe me, I like tinkering as much as anyone.

However, one must be realistic. Speaker placement in a room makes an immense difference. I advocate the use of a center speaker. Subs work well. We do hear the effects of gross improvement in frequency response exhibited by more sophisticated speaker designs.

IMHO, these are far better fields to plow than biwiring or bi amping.

I now reliquish the floor to the loyal oposition.

Best regards,

Gil

[matthew2]

Thanks a lot Gil. Lots of help

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Matthew

[Mighty Favog]

quote:

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Originally posted by William F. Gil McDermott:

Boy, I don't know how my name got brought up in this context. Except that I'm long winded.

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I didn't mean to imply your long winded. Really. Just thorough that's all.

[Colin]

excellent, long and detailed post by someone with three stars!

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Colin's Music System Cornwall 1s & Klipsch subs; lights out & tubes glowing!

[WMcD]

Thanks for the recent comment Colin.

Maybe buyers are faced with a choice and want some common sense advice.

1) I can buy "B" quality speakers and expensive wire, bi amping, bi wiring, etc.

2) Or I can buy "A" quality speakers and cheap wire.

IMHO, choice 2 is always better. If the salesman is pointing people to 1, I believe the buyer is being mislead.

Some of the tweek stuff is pure lunacy which wouldn't pass muster in any other field except "Hi Fi" where people are exposed to hucksters. For example, would a piano buyer believe that a spinnet sounds like a baby grand if only there are "vibration dampers" added? Not for a minute.

I've gotten far afield. It is a personal gripe. Our new friend had some ligit questions.

Gil

This message has been edited by William F. Gil McDermott on 01-09-2002 at 12:40 AM

[mike stehr]

I made twisted Cat 5 cables 12 gauge, I seem to like the sound of these over the 14 gauge audioquest

I used.

The audioquest seemed grainy sounding.

I went through all the trouble of

making this cable, of course it's gonna sound better.

IMO.

But I agree, you can get fine wire at Home Despot

for speakers cheap.

Just make sure the wire doesn't look oxidized.

Good clean looking copper.

You do agree that corroded wire will affect

sound quality, right Gil?

THANX!

[WMcD]

I would expect that corroded wire will affect sound. This is because it would effect the electrical characteristics.

I do wonder whether the wire we see is significantly corroded. Granted the outer few molecules are effected, but that is all.

It seems to me that the "wire" or any conducting part of our electronics, house wiring, voice coils, crossovers, etc., suffer some corrosion on the surface. At least where they're exposed to the atmosphere. Yet we don't have significant failures of these items because of surface corrosion.

I certainly believe that screw on connections should be kept snug and clean. From time to time we see failures because of an old connection.

Gil

[jnorv]

Goertz (Alpha Core) (http://www.alphacore.com/mispeaker.html) claims that they can measure the difference between good cable and theirs. They show the results of transmitting a 12 Khz square wave down a 25 foot speaker cable. Dont know when I last listened to a square wave.