Axiom Home Page Forums General Discussion Technical Questions Need a speaker switch to test single vs. biwire

I'd like to set up a speaker switch to do blind testing of straight, versus bi-wire cabling. I'd think relay activated would be preferrable over mechanical switching, but I don't know, and I'd like to be able to switch it from my normal seating position. I can't seem to find any such thing on the web, nor have I been able to find any plans or parts lists for such a project. I can't believe I'm the only guy interested in actually testing this kind of stuff without spending enormous amounts of money on professional panel switches.

Cliff, you're right that blind testing would be the only unbiased way of testing that, but it can't be done in the way that you described. The most important factor in blind testing is that the listener doesn't know which alternative is being heard at the moment; obviously just having him operate a switch can't do this and isn't a meaningful comparison. Having another person making the changes manually while you left, although it would take some time, is one way of doing this.

On the basic question of bi-wiring, this has been discussed here several times. The technical analysis of bi-wiring seems to clearly indicate that it's not significantly different electrically. In my view this doesn't raise enough of a question to call for personal testing of the point.

Cliff, we had quite a lengthy thread about this waaaay back in Deceber of 2003. I know that you just want to test it out for yourself with your own ears -- and that's admirable. Perhaps this thread will help you wrap your head around the whole debate.

Thanks for the input. I have read quite a bit of it here, as well as elsewhere on the web. To some it is "snake oil" while to others it's very real. I haven't found a single local sales person (high end audio stores) that won't swear it's the most profound experience in audio. Fundamentally I'd like to try it myself. I don't really care about making it absolutely an unchallengeable test. I simply want to set up a test environment that I can make work for me… my ears, my speakers, my electronics, my room, etc. As to switching it myself… I can stab the switch a couple of dozen times and confuse my mind as to which selection is active. Or have my son or wife hit the button a few times when I’m out of the room. Then switch it myself after that. If I can hear a difference; Especially if I can hear a positive difference, THEN I can check and see which set of wires are active.

It seems as if every bi-wiring thread ends up with some confusion between bi-wiring and bi-amping and drifts to a stop without reaching a conclusion.

There seem to be four different scenarios :

1. Some people argue that using multiple pairs connected in parallel at both ends give you the best tradeoff between resistance and capacitance for a given length of wire. I don't remember the details but the calculations seemed credible at the time. Having said that, this approach seems to be mostly used by people who have access to free cat-5 cable

2. Bi-wiring (two or more pairs of wires, connected in parallel at the amp but not at the speaker) seems the least likely to offer any real improvement other than possibly isolating the different impedence curves of the different drivers (ie the tweeter cable would not have to deal with current flowing into the 3-ohm impedence of the woofer when a 55 Hz signal is playing and therefore might eliminate some IR drop along the cable and produce a slightly purer sound) but IMO you can get the same result with a thicker single cable.

3. Putting a passive crossover at the amp rather than the speaker and bi-wiring from crossover to speakers. This seems like it *could* be beneficial but I've never seen it done.

4. Classic bi-amping -- active crossover before the amp, then different amp AND different speaker cables for each frequency range. This has all kinds of benefits, but some of them only apply when you're pushing the power limits of the amp (ie concert sound systems etc..) where overdriving the bass amp doesn't fry the tweeter and sometimes sounds pretty nice

You're talking about scenario 2, right ? One amp, with different speaker cables going to woofer and tweeter from the same amp connections ?

Seems to me that any time you are near the limits of wire size and distance there is the potential for getting slightly better sound by throwing copper at the problem. The question is not "do 2 14ga cables biwired sound better than 1 14ga cable" IMO but "do 2 14ga cables biwired sound better than 1 11ga cable" (or whatever).

Regardless of which scenario you want to test I have to think you have to switch at the speaker -- either a relay box at each speaker or a regular switch at each speaker would work, but you would need two assistants with switches.

A single DPDT relay / switch at each speaker would be enough. You would probably want to use a DC relay coil to be 100% sure that you weren't introducing any 60hz into the sound when the relays were actuated (although the chance of this is pretty slim).

Something like the following should work for comparing 1x 14g to 2x 14ga biwired :



Doing the more valid (IMO) test of 2 wires vs. one larger wire would require a 4PDT relay (or 2x DPDT) at each box. I'm not going to draw the diagram 'cause I have to go to work but let me know if you are interested.

Good luck, let us know how it works out. I have always wondered about this a bit but didn't have enough hope that the results would be worth the effort. I find some concepts real exciting but biwiring seems like a gimmick to me (until proven wrong, of course).

[EDIT] Let me know where you shop (hopefully something like Rat Shack with an easily accessible catalogue) and I can suggest part numbers for relay and switch. I do feel compelled to repeat that I don't think this is a good use of your time

Ooh, ooh, just thought of something. If you wire something up using the following diagram it would give what is IMO a much more valid test -- biwiring vs. the SAME two wire pairs in parallel so you aren't comparing "more vs. less copper".

The hookup is even simpler -- basically you're biwiring the speakers then using the relays to jumper signals from each wire together at the speaker end, just like the little brass jumpers which come with the speakers.

This one might be worth doing. Thoughts ?

You are correct... I am talking about #2. And thank you, this is exactly what I've been looking for. Unfortunately, as I read more and more about this topic, I'm forced to agree that this is probably a huge waste of time, but it also seems like a rather interesting intellectual/audio experiment. While shopping for speakers, it seems that most middle range speakers have terminals for bi-wiring, while the same manufacturers higher end models don't include them. I can't help but wonder if dual terminals is one of those "check box" items that costs little to add, and some buyers believe it better to have, even if they never use it. So it might prevent loss of a sale to a competitor that includes them.

For example, the French Speaker company Focal/JM Labs, includes dual terminals on the lower three lines of speakers. While the top line (Utopia) does not include them. Perhaps people buying $80,000 speakers have either listened to them, and want them anyway, or have never listened to them, but know they would look great in their $300k home theater. I read one interview (in Audiophile) http://www.stereophile.com/interviews/274/index2.html with the Focal president (Jacques Mahul), stating he only considers "bi-amplification" to be of use to fix defects in the drivers.

This seems to be another area of great audio contention, with little, or no scientific evidence to back it up. On the other hand, if I'd just spent $20,000 on two hunks of exotic wire for my speakers, you can bet that I'd hear a huge difference in the sound. Whether you would hear that difference or not, would be a more telling question.

It seems to me that including your switching device in series with the wires that you are trying test will alter your test results. The switches themselves have electrical characteristics that will interact with or over-ride the attributes you are trying to compare. Since we are talking about very small differences between bi-wiring and standard cabling, you wouldn't want to introduce another variable(the switch)into your test method.

BTW I have my M80's bi-wired, I don't know if it provides any benefit, but it is so cheap to do, I figure why not do it?

It certainly can't hurt anything!