How would I go about bi-wiring my center speaker? Thanks

I don't think you want to bi-wire your center channel if you are driving it from the power amplifier designated "center" on, say, a 1050. There would be no other amp with the center information as output. Now if you had the line level content of center, say, the pre-out from the 1050, you could drive two power amps in parallel and then bi-wire, assiming your speaker has separate terminals for the tweeter and midrange speakers.

Edit: Applejelly wrote a better post than my answer in the Outlaw to Outlaw forum under the 'Lack of Bass' post, so I deleted my original and recommend you check that one out.

S.

[This message has been edited by MrSandman (edited January 13, 2002).]

Sorry, my reply above was based on my reading the request as "bi-amping" instead of "bi-wiring" - my mistake. Nevertheless, bi-wiring doesn't sound like a good idea because you'll be subjecting both types of speakers in the box (assuming a two-way system)to a range of frequencies for which it was not intended. This is because the filtering action of the cross-over will be eliminated. most centerchannels are designed to deliver good quality dialogue so I think best to leave alone.

Bi-wiring your center channel with a reciever that doesn't support it probably will not do you any good. You will basically be doing to the same job as the brass or gold shorts connected to your binding posts. Bi-wiring just let's you send the lows to the lowpass filter and the highs to the high pass filter directly without having the crossover do the work. Some people say you can hear a difference though without the fancy hardware in your reciever. In my experience with designing and installing home theatres I have yet to hear it. Bi-wiring with a reciever that supports Bi-wiring does have an audible difference as well as Bi-amping. Mostly while listening to music or during the quieter more detailed scenes in movies. It all depends on your equipment. If you have real high end speakers let the crossover do the work. If there just middle of the road to low end speakers give a try.

I don't know why you want to bi-wire, but, go ahead and try it. I'll try to answer your question.

First, is your center channel speaker set up for bi-wiring? It must have 2 sets of input terminals that are currently connected by a jumper. This means that you must have two positive input terminals and two negatives.

First, remove the jumper between the 2 positive terminals and the one between the two negative terminals on your center channel speaker.

You'll need 4 lengths of speaker wire. (If you have bi-wire cables, then this is not applicable.) Take 2 of the the wires and connect them to the positive terminal for the center channel on your receiver. (You can twist the bare wire together, clamp them together with a spade, or combine them into one bananna plug.)

Take one of the positive wires and connect it to one of the positive input terminals on your speaker. Take the second positive wire and connect it to the second positive input terminal on your speaker.

Do the same thing for the negative connections.

Let us know how it sounds.

Chris

If you need, I have a small bitmap sketch showing this. Send me an email and I can send it to you.

[This message has been edited by Hi4head (edited January 14, 2002).]

Bi-wiring removes that gold plate in between your inputs which is nothing more than a big inducter that hurts sound quality. I personally own Klipsch RF-5's with the RC-7 center and RS-7 surrounds and RSW-15 sub, and im using an NAD T761 reciever to drive them all of them are biwired. And even though the NAD has no support for it by simply running two leads off of each output sound quality has been greatly improved. It adds a lot more air to the top end and a touch more mids and also helps to deliver stronger bass. BTW im using all kimber 8tc speaker cable which will help a lot if you are using something cheap like monster cable. I sale klipsch and NAD products and have seen many biwired and non biwired setups and anyone that can hear no difference needs to get their ears checked

The last response prompts another thought. (Although my comments should maybe be in another thread.)

A lot of folks simply replace the factory provided jumper with a good quality speaker wire. Some report that it provides a notable difference. While I haven't done this to my Monitors, it makes sense. Both the treble and bass sections of the speaker will see the same consistent sonic signature provided by the wire. (I think I'll go home tonight and do this.)

This isn't the same as bi-wiring, but is sure would be simpler, cheaper, and cleaner looking (of course, maybe some like to see multiple wires coming into the speakers - my wife doesn't).

I tried bi wiring Paradigm CC470 and Studio 20s FRL to my 990/7125. Had too much distortion and hurt my ears. Tried every adjustment and went back to single wiring.

"Will it sound any different if you biwire? Some users think it does, but I've never heard any differences, nor have any of our laboratory measurements or scientifically controlled double blind listening tests ever demonstrated there are audible differences. Axiom includes the extra terminals as a nod to those enthusiasts who believe that biwiring results in audible benefits and for the bi-ampers."

Alan Loft - Former editor of Sound & Vision and Audio Magazines

There seems to be confusion over what is happening in a bi-wired speaker. Electrically the circuit is exactly the same as having the shorting bar in place - the full range amplifier signal (or two identical signals in bi-amping) are fed to the inputs of the passive crossovers in the speaker. From there, the low pass feeds the woofer and the high pass feeds the tweeter.

The only thing different about bi-wiring is that the point where the inputs of the high pass and low pass crossovers are tied together is changed from the back of the speaker (the shorting bar)to the output terminals of the power amplifier.

The shorting bar is not a "big inductor". The inductor which is in series with the woofer, and forms part of the low pass filter, is still there, whether bi-wiring, bi-amping, or having the shorting bar in place.

After changinging from biwire to single, my ears still having discomfort with my 990/7125. have done the autosetup many times, adjusted the Xovers, sub gain and still can't find the sweetspot. my 1070 in the bedroom is perfect, never touch it. the 990/7125 is hooked up with an opticle cable to a dish vip622 would that be the problem?

Relating my comments in the order of the posts that ‘inspired’ each comment . . .

okc329 reports that bi-wiring will eliminate the passive crossover elements between the amplifier output and the loudspeaker drivers. For the simple bi-wiring and bi-amplification methods based on merely removing the jumpers between binding posts and running two pairs of speaker wire back to the amplifier(s), that statement by okc329 is not true. Unless you have opened the loudspeaker cabinet and gotten busy with cutters and/or a soldering iron, the passive crossover elements found inside the loudspeaker cabinet are still as connected as they ever were, interjecting filtering and other effects.

In a bi-wiring situation, what does removing the jumper accomplish? With the jumpers in place, either gold-plated blades or your own wiring, the two sections of the crossover network are linked by conductors, if installed properly, with a resistance of something on the order of 0.01 ohms or less, and, at audio frequencies, virtually no reactance between binding posts. (The wiring inside your loudspeaker has more resistance and reactance than the jumper blades between the binding posts.) Once the jumpers are removed and replaced with bi-wiring, the two sections of the crossover network are still linked, however the resistance and reactance from one set of posts to the other has increased on the order of 10 to 1000 times depending on the length and gauge of the loudspeaker cable runs. In bi-wiring, the voltage of all frequencies is present over the run of both sets of cables while the current running in each set is limited to the frequencies allowed by the individual sections of the crossover network still in place.

Similarly, jojajr’s statement that “bi-wiring just let's you send the lows to the low-pass filter and the highs to the high-pass filter directly without having the crossover do the work” is also partially in error. Bi-wiring sends all frequencies toward both sets of drivers, only the crossover sections still in place pass or impede the appropriate current at frequency ranges intended for each driver.

Another problematic statement was made by rennocneb: “Bi-wiring removes that gold plate in between your inputs, which is nothing more than a big inductor that hurts sound quality.” Although at audio frequencies and lower the differences are negligible, a properly made and installed gold-plated, flat blade style conductor will always be less of an inductor than a round (solid or stranded) conductor that conducts current throughout its diameter. (correction per mahansm's info below) At radio frequencies, where a great difference is pronounced, you will find grounding conductors are usually flat, and if round, are hollow, to greatly reduce inductive resistance to current flow. The statement by Hi4head that follows regarding the replacing of 1.5” of gold-plated blade with 1.5” of speaker cable falls under the same shadow of poor information. If 1.5” of your speaker cable would impart a ‘sonic signature’, you have got some really bad speaker cable.

I agree with the statement attributed to Alan Loft by mtrostel. Bi-wiring ‘improvement’ is not substantiated and requires ‘belief’, while bi-amplification (with active crossovers) is a different story.

If you’re going to run an extra set of speaker cable, over a long distance you’re better off running parallel lines, leaving the jumpers in place and reducing impedance between amplifier and loudspeaker – just don’t create a long-distance ‘short’!

For more, see this topic: Single vs. Split Pathways (bi-wire, bi/tri-amp, etc.)

(I've been writing while Altec and ksam were posting.)

Just a couple comments to BestBang4theBuck's post.

1. Silver and copper are actually more conductive than gold. Aluminum comes in fourth. Gold plating is used because gold does not develop a non-conductive (or poorly conductive) oxide coat (tarnish) as silver and copper do.

2. RF grounding conductors are hollow because of skin effect. As frequency increases, current is pushed to the outside of the conductor by self inductance. Since there's virtually no current flow in the interior of the conductor, it's cheaper (and much lighter) to make the conductor hollow. For a given cross sectional area, a flat plate has less inductance per unit length than a circular cross section and is easier to fabricate and install.

Lots of interesting info shared in this post.

While I can't say so 100% sure that bi-wiring speakers improves sound quality by any degree, great or small, I suspect it's a subjective matter maybe, depending on each individual's own ears\ability to hear or just it could be just wanting to believe hype to the degree that one can convince themselves that there is a difference.

Anyway; I gave bi-wiring a shot when I first learned about it and I really couldn't hear anything all that different, even though I had hoped I would, but what I did notice was that my Carver TFM - 22 amps ran cool instead of warm. maybe someone can explain the how, why and what of that.

I am still bi-wiring for that purpose alone, because although my amps are in a well ventilated cabinet, less heat generated just seems like a (subjective maybe) better idea to me. --- Mike

There is absolutely no reason that bi-wiring, or any other such connection scheme should effect the heat from your power amplifier. The heat coming from the amp at idle is determined by the standing bias current passing through the output transistors. This would not change with a different wiring scheme. The heat at high signal is totally dependent on the load impedance of the speaker and the power output of the amp at the time.

What this does indicate is that there is possibly something wrong with either your amp, the speakers, or the wiring. If for instance the amplifier was oscillating with your previous setup, that would cause the amp to get hotter, or very hot.

It is also possible that when you changed to bi-wiring, you cleared up a partial short which went unnoticed before.

At any rate, bi-wiring cannot have any effect on the amplifier if everything is operating properly.

Hmmm... interesting,

After I posted I got to experimenting a bit just to see if the same thing would happen if I did it using a different power amp. I use a Carver AV - 405 to power my center and rears, which aren't bi-wired and that amp has always run even warmer than the others.

Anyway; I fed a regular stereo source to it's normally for mains inputs and bi-wired my main front speakers to it. I played a couple of CDs then came back to see if it was warm and nope, it too was operating much cooler than it ever has. Then I swapped out the main speakers from my zone 2 and still the same cooler results.

That's 2 different sets of speakers and 3 power amps, could they all be bad and produce this same cooler operating effect? --- Mike

I have no idea what is happening, but It would be interesting to be able to do an analysis of it with some test equipment.

There is something more going on than it seems. Amplifiers just don't respond to different wires unless the load is considerably different. Bi-wiring does not change the load presented to the amp at all.

Altec,

Thanks for the replies.

Not knowing a great deal about what I should be noticing other than the sound degrading or something just not working at all; I too have no idea why this occurs and wouldn't even know what to ask a local repair technician to check out, plus I don't want to lug this stuff in and still have to pay them to find nothing wrong.

All I know is; It doesn't seem to be a problem as far as performance goes, I first noticed this difference in temps about 5 or so years ago, when I bought my first set of speakers that allowed me the option to bi-wire and explained how in the user's manual, (Paradigm Monitor 9s.) Nothing has noticeably degraded since then, in fact all is much better since I switched out my Rotel RSP-985 with the Outlaw 990.

Oh well; mine was only a shared observation with my gear only. Maybe I can find a way to contact someone at Carver and see if they can tell me anything about these older amps. --- Mike

T_Shirt... Out of curiosity, what type(s) and gauge(s) of speaker wire are you using, and how long is the run between amp(s) and speakers?

12 guage Monster with 6ft runs. I just followed what it said in the owner's manual for the speakers about the guage of the wire. --- Mike

Very Odd.....