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In Reply to: RE: Need some bi-wire counseling and opinions posted by JaroTheWise on July 12, 2015 at 00:42:00
if one is using the same amplifier source for both runs. The only advantage it gives is if one's wire gauge is a little on the thin side for the distance so you double up. Its still no replacement for an appropriate gauge wire based on run length.
Follow Ups:
See:
http://www.audioasylum.com/audio/speakers/messages/34/343710.html
a post in this thread, where I cite several pages of information, including circuit diagrams that show bi-wiring to be electrically different AND SUPERIOR than single wiring EVEN IF THE TOTAL WIRING GAUGE IS THE SAME.
I provide three major mechanisms that show bi-wiring to be superior to single-wiring, and back-up for those mechanisms is provided in the cited pages.
Jon Risch
I'm an electrical engineer and stopped reading this article after the fourth paragraph. There are so MANY MANY errors in this article. See my responses below.
Edits: 07/24/15 07/24/15
If you are an electrical engineer, then you should be able to comprehend the Fig. 1 thru 6 at:
http://www.geocities.ws/jonrisch/biwiring2.htm
and the further pages referenced.
RE the 1st page, that is more of an explanation for laymen, and does not go into technical details as such.
RE your being an electrical engineer, good for you. I am a Senior Project Engineer at Peavey Electronics, and make my living designing loudspeaker systems. I have written several AES articles, and presented at several conferences, and have several patents to my name.
So rather than dismiss that which you won't bother to read, or perhaps, don't understand, I suggest that you either retract your baseless claims of technical errors, or bother to read the actual pages through, and then comment intelligently on them.
Jon Risch
I couldn't access the links. Who wrote the articles?
The links worked OK for me one second ago. Jon Risch wrote the articles, I believe.
Yet another error in this description. I agree that the removing the jumpers from the speaker terminals isolate the crossovers but that's it.1) First of, it should be noted that speaker A and speaker B terminals are not seperate channels as incorreclty assumed by the author. They are in fact parallel taps of the output stage. So the output stage see's the speaker in its entirety, both woofer and tweeter when biwired.
2) Furthermore, the amplifier output sends full bandwidth signals across the speaker terminals because its both physically and electrically the same output stage. It cannot send different signal bandwidths from the receivers speaker terminals as they are connected electrically and physically across the same output stage.
"The situation is such that when the full range musical signal is applied to the terminals of a full-range speaker system, the woofer only gets sent low frequency signals, and the tweeter only gets sent high frequency signals. Once the crossover networks have been electrically separated, they still continue to function in the same manner, having a low impedance in their passband of application. This means that if separate speaker cables are hooked up for the woofer and it's portion of the network, and the tweeter, and it's portion of the network, not only have the speakers and the frequency's directed and divided for them, but the two separate speaker cables will now also carry different signals, the woofer cable mostly the lows, and the tweeter cable mostly the highs.
Once the highs and lows have been separated in this fashion, the strong current pulses and surges that a woofer demands when reproducing bass or drums will not interact with the delicate sounds of a flute or cymbal. The magnetic field of the low frequency signals cannot modulate or interfere with the highs, and to a lesser extent, the reverse is true. "
Edits: 07/24/15
RE your comment #1, I am not sure what you are trying to say, since you reference Speaker terminals A and B, which I do not in my pages.At the second page, I have Fig.s 1 thru 6
At the third page, I do have a Figure A and a Figure B, but these are clearly labeled, and Fig B does show the results when the crossover is present. Figure A was shown to provide the raw data of the actual output of the drivers themselves when driven by the other driver in that same cabinet.
If you are referring to the third page, then I don't know where you are coming from, Nothing incorrect there, just data never before presented regarding the effects of sound impinging on the loudspeaker components.
While your comment #2 is a true statement, it has nothing to do with the signal once it LEAVES the amp terminals and starts down a path to the speakers. The CURRENT in a set of bi-wire cables IS different, because to the impedance being different.
That is shown clearly in Fig. X, at the page 7 section.Again nothing incorrect here, and again, information never before shown to the general public before.
These things are the result of fundamental research into the operating principles of bi-wiring.
Of course, if you don't really understand the information presented, then that could explain your confusion, and why you think it is wrong.
Jon Risch
Edits: 07/26/15
Biwiring (not biamping) is the process of using both speaker terminal pairs of the receiver and connecting them to the speakers terminals with jumpers removed is it not? Answer this one question first and then we'll move on.
Edits: 07/29/15
I cover some of that in this recent post:
http://www.audioasylum.com/audio/speakers/messages/34/343950.html
A receiver with an A and a B output is not necessarily the best platform to implement bi-wiring, because of the methods used on some receivers to engage both the A and B speaker outputs at the same time.
RE the jumpers, this would be the case for a loudspeaker designed to be bi-wired, that had a set of jumpers at the speaker.
But yes, basically, if the receiver A and B outputs are paralleled when both are engaged, and you run a separate speaker cable from the receiver/amp to each section of the loudspeaker crossover, what you describe is what is commonly referred to as bi-wiring.
Before you dismiss anything, at least look at this page:
http://www.geocities.ws/jonrisch/biwiring2.htm
at Fig. 1 and Fig. 2, and the related charts at the bottom.
This is _one_ aspect of three or four major aspects of bi-wiring.
You will have to do some reading and think about the issues for a while.
Far too many people make the mistake of assuming that there is no electrical difference between single wiring and bi-wiring, but an honest look at the facts will show this to be otherwise.
Jon Risch
Biwiring then offers no advantage what so ever as the output of the amp/receiver is the same point electrically and ultimately controls the drivers whether they are controlled through a single pair of wires or biwired. The vector sum of the amps response through biwiring equals that of a single wire input because to the amp, it sees the complete impedance relationship. Your logic completely ignores this point which is the biggest failing of your arguement.
Your mind is so closed, you can't even be bothered to look at the circuit diagrams I reference.
No point in continuing a discussion then.
Jon Risch
because you throw around pseudo science and incorrectly applying engineering principles to confuse the uninitiated or the untrained. This type of BS is what gives audiophiles and HIFI a bad rep. EOD.
Your statement "the amp sees the complete impedance relationship" is of course true.
It's the cables that see different impedances, due to their different frequency loads.
The value of bi-wiring is highly debatable, but the electrical properties of the circuit is not.
That just isn't true. In the crossover transition band, where the two sides of the crossover are both conducting, the bi-wired circuit is not equivalent to the single wired circuit. The impedance seen by the amp is different in that frequency band. Further, when you consider the woofer to be a voltage source due to its generation of back EMF, it's pretty easy to see that the amount of back-EMF reaching the tweeter is different in the bi-wire case than the single wire case.
You guys keep forgetting that its all connected to the same source, the only difference being that biwiring uses two physical connections on the same electrical source so what ever back emf affects one line will affect the output stage as a whole. If there were two seperate sources, I would agree with the argument but this would be called bi-amping, not bi-wiring. What has been written about bi-wiring is mathematically and theoretically incorrect.
The amp can be modeled as a voltage source with a series output impedance. When the woofer is acting as a generator, it produces a back-EMF of V volts at the LF speaker terminals. In the single wire case, all V volts of back-EMF are presented to the HF speaker terminals. In the bi-wire case, the wire impedance and amplifier's output impedance become a voltage divider. A typical output impedance for a solid state amplifier is 0.01 ohms. A typical speaker cable impedance is 0.05 - 0.1 ohms. So the back-EMF present at the amplifier terminals is V * (0.01/0.05) to V * (0.01/0.1). So in the bi-wire case, only 10-20% of the back-EMF present at the LF terminals is presented to the HF side.
At lower frequencies, the back-EMF is blocked by the high pass filter in the HF crossover anyway. But in the transition band where both crossover networks are conducting, the woofer drives the tweeter more in the single wire case than in the bi-wire case.
Still connected to the same source and its the source that controls speaker movement. Everything is being examined at the speaker end but you guys fail to bring it back to the source. The analysis is incorrectly seperating the source to two independent points which its not. This makes the modelling incorrect and flaws subsequent analysis.
Edits: 07/31/15
In the case of back-EMF, the source is in the speaker and the amp is the sink.
The cable impedance itself changes when going from single wiring to bi-wiring, at least in the crossover transition band. So even without back-EMF there is a difference. But I assumed you weren't a "cable guy", so if you don't think the cable impedance is significant in the single wire case you wouldn't think the difference between single and bi-wiring is significant either. That's why I made a point of back-EMF.
When was this article written? The first paragraph is technically incorrect and inaccurate by today's standard as each channel is a dedicated channel, not a derivative of left and right channels and its full bandwidth.
"You might want to try bi-wiring, but it helps to use something better than just zip cord, no matter what the gauge.
If you are running 10-12 foot lengths, a decent single wire set of speaker cables will run around $140 or so, so
double that for bi-wiring the two front mains. I would not worry about bi-wiring the center speaker, or using
anything but 12 gauge zip for the surrounds, as the suround signal is processed through a cheap digital delay
as well as derived from signals buried in the main signal, and hence is not that clean or wide bandwidth. "
The 1st page, 1st paragraph was written about 16 years ago, and back then, the HT receivers were using derived analog signals for the rear channels.
Now, with all digital and discrete channels, things are theoretically better, although I have to say, most modern DVD's don't sound a whole lot better sonically than they used to, despite the technology.
I should re-write that paragraph, but I pointed to some existing pages, that were "ghosted" from the old Geocites web sites, and I do not have access to those pages to edit them. They were however, convenient to point to without sending some one to the Wayback Machine (internet Archives)
Jon Risch
Over 20 years ago, AFAIK
Jon, this may be a dumb question, but in a 2-channel amp with A & B outputs, is it preferable to connect both wires to the A terminal, or one wire to A and the other to B?
Or, it doesn't matter?
Thanks
Many amps/receivers put the A and B output in series when both are engaged. This would be a bad thing for bi-wiring, and would not work at all.
IF the amp puts the outputs in parallel, then it would be OK to use them as you state: "one wire (pair) to A and the other (pair) to B".
Jon Risch
Thanks, Jon.
I have said that I plan on doing some more A/B testing since I believed that from the beginning - or at least that if it has benefit then the benefit is exceedingly small and not noticeable in a "mid-fi" system like mine.
If it does occur then I keep thinking it would be for a reason other than really having two runs - like more metal contact at the connections or something such. My wires are not long enough or thin enough to constrain the signal at all in that regard
JaroTheWise
You will not be surprised by the results. :)
Bi-wiring, done competently, should have no negative impact. Whether there is a positive one is debatable (as is being done here).
The subject line should have read... "You will know soon enough"if biwiring was done correctly or not. Incorrectly shorts out the amplifier's output stage which if the protection circuits don't catch will blow out the output stage. :)
Edits: 07/17/15 07/17/15
Yep. This happened in a dealer's store when they set up some speakers for me to audition. I guess it was a little easier to short out the speaker terminals since they were using tri-wire cables. I suppose it only blew the fuse. It was an integrated tube amplifier, C-J, I think. I made them get a SS amp, which sounded better with those speakers.
I've just been using 12 gauge cables for many years.
-----
"A fool and his money are soon parted." --- Thomas Tusser
I've been running 14 Gauge to the mains as my runs are short and 12 gauge to the surrounds because of the distance.
When you consider how good some placebos are that's saying a lot.I think I've heard some positive changes or differences in the sound after bi-wiring, but all wiring schemes sound good in at least some ways. Slap down some wire and start playing the music.
Edits: 07/17/15 07/18/15
Not really.. A placebo isn't real and anything that seemed a cure for an ailment is simply a state of mind. Same goes to hearing gains in biwiring. Its a state of mind, not a reality.
I can only hope for such a thing.
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