Two sets of wires to each speaker: Helpful or gimmick?

[wgscott]

I bought some speakers (pictured below) that have two sets of terminals (optionally, if you remove the coupling), one for the base, and one for the mid-range and tweeter. Since I had the option of running two sets of cables to them, I did. Since it is hard to toggle between configurations, I haven't tried to blind-test my impression that they sound better with two cables.

 

From the point of view of the wiring, I am at a loss to understand why it would make any difference. The assertion essentially amounts to whether it makes a difference to have the terminals connected to each other at the amp vs. at the speaker. Does it, or is this just folk-lore?

 

[John]

Not a gimmick, for sure. Because the crossover sections are connected independently, if you biwire, each set of cables carries a different frequency range. This is measureable and well documented. There's a sound rationale as to why that's a good thing, lowering IM distortion between the frequencies etc... So, yes, useful. Only you can decide whether it's worth the cost of an extra cable run but if you hear the differences, you are likely not imagining it.

 

- John.

 

[wgscott]

Thanks. I already did it, but I decided to implement relatively inexpensive potential improvements like this first, rather than buy expensive designer cables, which I guess I can try later sometime after I win the lottery (which I never play). So it probably cost me $100 instead of $60 (in extra wires and banana plugs).

 

[Glenee]

My experience has been that it is speaker dependent. As a example. Every set of B&W I have owned, have benefited from Bi-Wiring. I have a set of Aerial 9's now and they sound better with single set of wires and jumpers with the main feed from the Amp tied to the top and midrange. The B&W's have always with every Model did better with the Bi-Wire, those being 802D's and 805S's. It is very much a speaker based choice.

Try both and listen.

Good Luck and Good Tunes

 

[Joshua_j]

I am not an expert, but bi-wiring does not carry a different set of frequencies. This only occurs of there is an external crossover before the amplifier section. If you are running 2 different sets of wires from the same amplifier then you are sending the same signal (range of frequency) to both.

 

Joshua

 

[davidR]

To take advantage of two sets of terminals as far as hearing differences in sound quality usually involves bi-amping; using a pair of monoblock amps for each speaker making four amps total, or using a pair of stereo amplifiers, (one amp for the highs + mids, and one for the bass).

 

[Joshua_j]

but also, there must be an external crossover (to split the signal between highs and lows) between the pre-amp and the amp. Otherwise, you are just sending the same signal to the two separate amps and accomplishing the same thing as bi-wiring.

Joshua

 

[John]

@joshua.

No, I am talking about biwiring.

I do understand the difference.

You are totally mistaken.

With biwiring each cable run does carry a different frequency range.

 

 

[Glenee]

When you BiAmp and use seperate speaker post for each Amp, you will hear a difference. If it is not set-up right what you hear will not be better. When you BiAmp there is alot more involved than just speaker wire and connectors, As you already know.

 

[Shadorne]

Unless you bi-amp it is probably not worth the trouble. If you bi-amp then there are benefits in terms of a reduction of IMD distortion.

 

Of course, active speakers is really the proper way to do this as a passive crossover is just adding unecessary load and distortion (expescially the capacitors)

 

[wgscott]

 

... bi-wiring does not carry a different set of frequencies. This only occurs of there is an external crossover before the amplifier section. If you are running 2 different sets of wires from the same amplifier then you are sending the same signal (range of frequency) to both.

 

 

That is what I suspected.

 

[tomE]

I have limited experience in this but I did bi wire a pair of Martin Logan Aerius speakers and it made a pretty obvious difference for the better. Other speakers I have tried this with have been a mixed bag of relatively minor differences.

 

[Joshua_j]

I don't like back and forths through email because things can get misconstrued- such as was your tone towards me surly or not? I have no idea so I choose to think not and just would like to learn more. I read these a long time ago and have read many other articles on DIY audio, avs forum, and other places. I spent a lot of time researching this about a year ago. Here are a few articles supporting my point.

http://www.theaudiocritic.com/downloads/article_1.pdf

http://en.wikipedia.org/wiki/Bi-wiring

http://en.wikipedia.org/wiki/Active_crossover

 

I don't think that these articles support your understanding, but rather they support mine. If you can direct me to refuting data that would be great.

 

Joshua

 

[John]

To clarify: I am not saying that the audible differences are significant. I am not saying that one should biwire. I am not saying that biwiring produces as pure a separation of the signal as bi-amping with active crossovers. I am merely stating the fact that the frequency content of the circuit to which each set of cable participates will be different. (although I would be willing to read any research that shows otherwise).

 

Let's not forget that the output of and the signal in the speaker cables is load dependent. Try shorting one set of cables and not the other for an obvious demonstration. With biwiring you are not connecting to the drivers but to discrete sections of the crossover network. (When you put the jumpers back in, all that happens is that the sections get reconnected in parallel.) So...each cable run sees a different load; one a hipass filter and the other a lopass filter, so they naturally carry different signals (electricity is not one-way).

 

Here are a couple of decent articles, though there are many more out there...

 

http://www.audioasylum.com/audio/cables/messages/4953.html

 

http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/audio/biwire/Page1.html

 

@Joshua, yes my response was intended to be surly. I apologize. Your post began with 'you are talking about bi-amping' and I am none to keen on being told what is going on in my own mind.

 

- John.

 

[Joshua_j]

@John, let me apologize for writing in a way that could taken wrong, and I did not mean to tell you what was going on in your mind. Thank you for those links... no matter how many times I try, the math just bounces off my brain like al dante pasta off the wall!!! Another link that I have found http://www.diyaudio.com/forums/everything-else/70202-audio-lies-13.html. I have read most every page. and am none the wiser except that it seems like bi-wiring might be beneficial, might not. Wire gauge is important, distance from amp to speaker is important. But mostly, I should just enjoy the music because the math is beyond me......

Joshua

 

[roccoriley]

There are some speaker cables, for example MIT, that have a box full of electronic gear in the speaker cable itself. In a biwire configuration the cable ends are marked to indicate the high and low frequencies.

 

[barrows]

Whether or not biwiring (not referring to biamping here, just biwiring alone) results in improved performance, remember the following:

One should compare the two sets of speaker wires (I hope these are identical) connected both in a biwire configuration and a single wire configuration:

1. Biwire: two sets of speaker cables, one connected to the mid/high frequency binding posts, and one connected to the low frequency binding posts.

Versus:

2. Singlewire (but with both cable sets): two sets of speaker cables, both connected to the low frequency binding posts, with jumpers connected to the high frequency binding posts.

If one does not make this comparison, any improvement heard with biwiring may be due to just the increased aggregate gauge of the double cable run versus running a single set of cables, and may not be due to the separation of mid/high and low frequency cable runs.

In my experience, the relative effectiveness of biwiring is entirely amp and speaker dependent, and will not be consistent in all systems.

 

[mjb]

From the links above, the wikipedia article is spot on.

Top: normal connection. Bottom: bi-wiring.

 

 

 

The circuit diagram is the same in both cases, but the bottom picture uses twice as much wire.

Therefore, the benifit of Bi-Wiring can be no more than using a signal bigger wire. Ipso facto!

 

 

 

[symdex]

The drawing is accurate. The improvement of biwiring is because the 2 drivers are separated from each other and have individual crossovers. Drivers have complex impedance, back emf interactions, and intermodulation distortion effects that can be reduced by isolating the driver/crossover networks. In effect the amplifier sees a simpler load and can maintain maximum damping factor control. If a loudspeaker

was designed and "voiced" to be bi-wired it will sound better. Many products however, just jumped on the biwire bandwagon and added extra binding posts to be in fashion. Also, some loudspeaker designers have preferred to be single wired having accounted in the crossover with impedance matching circuits, (zobel filters)and feel that they can provide a better end user experience by limiting the variables involved in hookup. The quality of those free jumpers that come with

biwireable speakers is very detrimental to good sound. In short ,if the speaker is biwireable it should sound better biwired and if you decide not to biwire replace the jumper with the same quality of speaker cable that you use for the main runs.

 

[Shadorne]

Good point. The differences can be expected to extremely small in this example. Only a very low impedance speaker with lengthy high impedance speaker wires might produce some slight differences.

 

The modest benefit comes (IM distortion reduction) from adding two power amplifiers to drive each speaker driver separately. This setup is called "biamping".

 

The huge benefit comes (crossover distortion reduction/better driver control/better phase compensation/higher efficiency/further IM and THD distortion reduction) from removing the passive crossovers and filtering the line level signal to the two power amplifiers tuned to drive each speaker driver's bandwidth separately. This setup is called an "active speaker".

 

Active speakers can be an order or magnitude better in lowering the distortion floor. Good active designs can achieve distortion levels commensurate with electronics. Passive designs cannot begin to compete from a technical perspective - although a passive design may sound better depending on the relative quality of each implementation.

 

[wgscott]

I bi-wired mine before I gave this any real thought (I posted after the fact). I bought 100 ft of Blue Jeans cable so the only additional expense I had was 4 extra banana plugs (I didn't have anything else to do with the wire).

 

After I did the high-school-physics-level calculations, I realize there isn't any physical basis to the claim that the circuits differ in any significant way (the simple wiring diagram says it all). Assuming the length and gauge of the wire don't limit performance (25 ft, 12 gauge should be safe), there is no significant difference in the inductance, resistance, etc of the wire either way. I also doubt that a gold-plated metal bridge between the two posts would be any worse (or better) than speaker wire. More wire = more opportunity for something to go wrong.

 

I am going to put the wires under the floor soon. I think I will use two cables rather than four, and put the original jumpers back on.

 

[blueixus]

If you going to put them under the floor you may want to put both runs in in case:

 

1) You have an active system one day

2) You decide to Bi Amp (rather than Biwire)

 

Of course if you don't mind going under the floor feel free to ignore this comment!

 

The advice on the jumpers is however good.

 

They are usually as bad as it comes, this is easily solved with a short run of silver cable from Home Grown Cable at about $6 a foot. You probably only need a foot or so to make some bridges from bass to treble.

 

[wgscott]

Yeah, I thought of the bi-amp upgrade right after I posted. What one should I buy?

 

I'm really not trying to be difficult, but why would replacing the gold-plated jumpers with wires be an improvement? I have plenty of wire, I just don't understand why they would be inferior?

 

[Paul R]

Impedance, and current carrying capacity, among other factors, come into play with bi-wiring. Given that, the better the cable you use, the less beneficial effect bi-wiring has.

 

Try wiring up a set of speakers with say, 20 gauge zip cord, then bi-wire it wit the same cord. You are almost certain to hear a rather dramatic improvement in the sound.

 

The same thing with heavy gauge decent speaker wire may not make any discernible difference in the sound at all.

 

The above is true in my experience, but YMMV!

 

-Paul

 

 

[CharlyD]

A very good analysis of the possible effects of bi-wiring may be found here - http://www.audioholics.com/education/cables/bi-wiring-from-amplifier-to-loudspeaker. Essentially, his analyis shows that the effect of bi-wiring is extremely small as long as the impedance of the speaker wire used is sufficiently low. Just use a single cable of sufficient gage and all is well.