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Old 25th November 2016, 06:44 PM   #1
Roobarb is offline Roobarb  United Kingdom
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Question Cross overs and Bi Wiring

Folks
Have been reading up on bi-wiring, it would seem that the most popular answer as to why it improves matters is that the frequencies are split meaning the tweeter cable doesn't get 'overloaded' with bass frequencies. Ahem, all very good, however surely the cables carry all frequencies from the amp to the crossovers which then band pass them into high and low.. I can possibly see that the return current to earth may carry a subset of frequencies after it has been filtered by the XO, but not the current from the amp.... (?)
I am currently putting together bits to make a pair of TLs and the XOs will be a separate box, not internal to the speaker. This whole bi-wiring business got me wondering, if there is merit to this splitting up of frequencies theory, would it be best to have the XOs next to the amp, and then do bi-wring by essentially having speaker cables from the XO to each individual driver in the speaker, this way the longer cables certainly will carry just the hi or low frequencies..
I've not seen this done before so am assuming there is some terrible downside to doing this that I know not of..
Can anyone enlighten me ?
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Old 25th November 2016, 08:28 PM   #2
DougL is offline DougL  United States
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Just some random thoughts from the peanut gallery:
In a bi-wire scenario, the voltage is the same on both cables.
The current in a closed loop = 0. In other words, the current after the filter is the same as the current before the filter.
Thus, the current in the two cables could / will be different, even though the voltage is the same.

Does this have a real affect? I am not convinced its significant.

As for your idea of putting the crossover by the amp, the only disadvantage are:
1. Electrical properties of the cable could potentially affect the crossover.
2. The extra cables are required.

This is DIY, I think you can try it.
I don't see any show stoppers here.
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Last edited by DougL; 25th November 2016 at 08:29 PM. Reason: Formating for readability
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Old 25th November 2016, 08:58 PM   #3
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Bi -wiring is a waste of time , just marketing hype by manufacturers when everyone jumped on the bandwagon a few years ago. Many companies that sold bi-wired speakers claiming massive improvements at the time have revertred to single wire as they claim no " significant " gains from bi-wiring . The only gain was made by cable manufacturers
That's not to say you shouldn't try it , after all experimentation and building is half the fun , just don't expect night and day changes.
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Old 25th November 2016, 09:06 PM   #4
chrisb is offline chrisb  Canada
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This has been beaten almost to death many of us had hoped. If crossover pass sections are fully isolated, and if each is driven by separate amp channels, there could be some benefit to passive multi-amping, but nowhere near as much as with true "active" systems, where the essential band pass filtering is done ahead of the multiple amps. That can be achieved by either passive line level XO, actively (analog) , or as has become very popular of late by DSP - minidsp and the like. The latter offers so much more than just simple pass filtering.

But bi-wiring alone can be considered a great marketing tool for selling more cabling and fancy audio nervosa grade connectors.

How's that go ' Been there, bought the T-shirt" ?
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Old 25th November 2016, 09:07 PM   #5
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Hi Roobarb, I think you have part of the pro-bi-wiring argument, in that you split the current, but not the voltages. This would minimize self-inductance and skin-effect.

What's missing and where I think most of any differences would be found is doubling up cables has an effect on the overall speaker cable inductance and capacitance as well. I could see this having somewhat of an effect, but I could not see it necessarily being better or worse.

This also gets into area I've been curious about, which is how much of the feedback loops in amps are affected by EMI/RFI pick up in cables. But that's a long story which I am sadly unable to experiment with for fun.

I am also unable to justify much of a spend on bi-wiring. I mean, sure, if you are using 14 gauge brand-less speaker cable at $0.50 a foot, go ahead,but I could not in good conscience suggest anyone buy expensive speaker cables for the sake of bi-wiring.

Best,


Erik
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Last edited by eriksquires; 25th November 2016 at 09:11 PM.
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Old 25th November 2016, 09:23 PM   #6
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You guys didn't catch what OP wrote: he wanted biwire AND external


yes, but EXTERNAL is different, few makes it
And biwiring is stooopid, set on good cables, better...


I think, and I'm sure, that this reptilian way of behavior
we have assisted many times, will continue on and on, and the wife, and the children, and the all-in-the-box

WAKEEE UP !!

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Old 25th November 2016, 09:25 PM   #7
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Pico,

Yeah, I saw. External removes chances of the crossover being microphonic. Great.

Best,

Erik
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Old 25th November 2016, 09:27 PM   #8
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It's just a *star ground* in reverse...
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Old 25th November 2016, 09:40 PM   #9
Lojzek is offline Lojzek  Croatia
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Quote:
Originally Posted by Roobarb View Post
Can anyone enlighten me ?
You're trying to find a solution to a problem that doesn't exist.
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Old 25th November 2016, 09:49 PM   #10
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Quote:
Can anyone enlighten me ?
Don't waste your time. if you want significant improvement, go active. There are many, many more people running active on this forum than bi-wiring. I run active only and wouldn't bother with passive and certainly never even consider bi-wiring. If I want magic tricks, I'll go to a circus.
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