Bi-Wiring: Fact or Fiction?

[GeniX]

Yeah I spoke to some of you on the forums about this - and thanks for the discussion. Im hoping to guage a number of other peoples responses...

when I bought my Polks the salesman asked if I were planning to bi-wire them. At first I spoke as if he meant bi-amping, but he corrected me and said no - running two sets of cables from the amp end to the speakers 2 terminals.

Now, aside from putting your own external cross-over in (as I think ProAc_Fan mentioned to me), why would one want to bi-wire?

[ProAc_Fan]

Actually Genix I think you misunderstood me. BY biwiring you bypass the speakers built in crossover. Also if you use two amps you can use a larger one to power just the bottom end of your speaker.

[GeniX]

You're right, I did mis-understand you. And with bi-amping, there is no need for a crossover, right?

[MikE]

GeniX -

While not a big proponent of bi-wiring, having not studied the various applications extensively, I have used a bi-wire configuration since the Silverline Sonatinas have taken residence IMS. Why? The designer, Alan Yun recommended bi-wire in our exchanges prior to purchase and based on my limited obeservations found ANY bi-wire grouping (of the cables I had) preferred to a single-wire / jumper configuration. Let me qualify that statement. The differences or improved performance was discernable but discrete. It sounded slightly better with the seperate cable runs for top and bottom post. Was it worth the additional cost of another 10' run? That is a individual call, though seeing I received one pair of Silverline speaker cables N/C with the speakers and another at 50% off, it was.

During my 2 1/2 year romance with my Sonatinas I've challenged the Silverline cables to some up and comers but have not found a better value. I recently replaced the copper Silverline cables on the top post with a DIY 24awg 99.999% pure solid silver w/20awg teflon. Not only was this MUCH cheaper but the narrow gauge silver was more compatible with my new SET amp (as rumored). I hope to upgrade the other pair of Silverline cables with another homebrew DIY cable; a continous cast copper 12awg.

MikE

*What is bi-wiring?

"Bi-wiring is where the crossover inside the speaker has been separated into it's HF and LF sections, and separate pairs of connecting terminals provided to access those separate sections independently. Normally, the LF and HF crossover sections are in parallel, connected internally to the same single pair of binding posts. For single cable use, a set of jumpers is provided to bridge the terminal pairs, paralleling the separated crossover sections outside the cabinet instead of inside."

"Then, separate speaker cables are run from the same amp output to these separated pairs of terminals at the speaker."

*What good does bi-wiring do?

"Some say that any improvement in the sound it makes is strictly due to the decreased total DCR, and this makes the speaker less prone to frequency response variations due to cable resistance. According to this view, simply running the two cables in parallel at both ends will do the same thing. In my opinion, this is a very simplistic and incomplete way of looking at the situation."

"Once the crossovers have been electrically separated, they present different impedances (loads) to the power amp within their passbands and outside of their passbands. The woofer and corresponding low frequency crossover section will present a low impedance at low frequencies and a high impedance at HF, while the tweeter section will present a low impedance at high frequencies, and high one at LF's. "

"With the electrical separation, differing currents will flow within the two cables that make up a bi-wire set. For the separate cable feeding the woofer section, a lot of current will flow at LF's but not much current at HF's, and the tweeter cable will have some current flow at HF, but very little at LF's. A division of labor has occured with bi-wiring, whereby a single cable does not have have to carry the HF currents simultaneuously with the LF current."

"Two things happen due to this:

1. The losses in the cable due to "eye-squared-are" losses (current squared time the resistance equals voltage drop) are reduced for each frequency band, so that any tendency for the woofer to modulate the tweeter due to current draw is greatly reduced. This form of IM would be in lock-step with the original signal.

2. The magnetic fields due to the HF and LF currents have also been separated out, and any tendency for them to intermodulate and cause sonic artifacts has been greatly reduced. This form of IM would be occuring both at the same time, and in a time delayed form due to mechanical resonances and motor/generator action.

See http://members.xoom.com/Jon_Risch/page7.htm for a more in depth discussion about the benefits of bi-wiring."

*Can I use the A and B outputs on my receiver to bi-wire?

"While this would be very convenient, it can only be done if the outputs are placed in parallel, rather than series. Many receivers and integrated amps that have two speaker outputs will connect them in series when they are both selected at the same time, to protect the amplifier from an excessively low impedance. Check your owners manual to see how the A and B output are wired when they are both selected. A simple test would be to select them both with a speaker only hooked up normally to one of them, if the sound goes dead, then they are connected in series, and you will need to connect both of the bi-wire cables to one pair of output terminals."

*Should both cables be the same kind?

"This is not absolutely necessary, although it can be argued that certain sensitive speakers need the same exact cable in order to minimize any discontinuities in the midrange (crossover region). However, as long as both cables are of a high quality, this is much less of a problem than it might seem. An extreme example would be to use heavy gauge zip cord for the woofer, and an exotic high performance cable for the highs. Some audiophiles have used this approach to great effect, and others found the zip cord on the woofer holding them back. It never hurts to try, and see how well a particular pairing will work for you."

*Should both cables be the same length?

"This has already been answered above, but many people seem to feel that bi-wiring is even more critical, so the warnings in the answer above about matching length for electrical reasons are perhaps even more relevant."

*Are the bi-wire cables that are all in one jacket as good as separate cables?

"Many cable manufacturer's offer an all-in-one bi-wire cable, primarily for convenience and a tidier wiring arrangement. If you read the explanation of how bi-wiring works, then you would realize that placing the cable's magnetic fields in close proximity within the same cable jacket may compromise the bi-wiring advantage to some degree. Most experienced audiophiles agree, totally physically separated bi-wire cables tend to sound better than those in a common jacket. The degree of compromise is going to depend on the spacing between the bi-wire sections within the common jacket, and how much magnetic coupling and motor/generator resonances are going on inside the common cable jacket."

JR

[GeniX]

Thanks for the response, MIKE>

I personally do not think bi-wiring will sonically make a difference, but was wondering whether there is real reason for it, or whether its just more audiophile voodoo.

[THOR]

Well I am not an audiophile, I am more of a noobaphile but will tell ya what I know :D

I can tell you this my CV's sounded better bi-wired than not, and they sound 100 times better bi-amped. I think this is because my speakers were built to be bi-wired or bi-amped. There are two sets of posts one drives the 15" woofer the other drives the rest, 12" woof, two 5" mids and the tweet.

(1)I've hooked them up the normal way using a jumper to connect the two sets of posts and then a single wire to the reciever, (2) I've hooked them up with seperate wires going to the same channel of the reciever and (3) with one going to the "A" channel and one going to the "B" channel, and (4) I have hooked them up with seperate wires going to seperate recievers that are tied together.

I can honestly say I hear a difference in all 4 set ups:

#1 sounds better than #3

#2 sounds better than #1 and #3

#4 sounds wayyyyyy better than all the rest.

Does #4 sound so much better because the speakers are getting another 110wpc than in the other setups?? Maybe, my CV's specs recommend 500 continuos watts minimum (of course Thooty and others mock me about this since my speakers sensitivity is 100Db or so, I have still yet to break a window so I think the specs are spot on) I would be interested in hooking a 200wpc+ reciever up in #2 mode and comparing to #4 to see. Alas that testing will never occur since my next purchases will be two 200wpc+ amps to bi-amp my CV's.

And for all you doubting thomasinas who wonder at my scientifical abilitiations to be able to perform such complex and diffcult testing, the same format, songs and volume levels were used in all tests and no ALCOHOL was present at the time :D

[angela]

that cheesy smile is NOT all that convincing, Thor:D


Seriously, you hit it right on the head. I believe that until we try it in our own system, we don't/can't know what the effect/result will be.

It may seem like voodoo, but there are so many variables to create a black and white formula or rule of thumb.

You did eXActLy what folks should do, in my opinion.

Try it FIRST and THEN make a judgment.

cool -
angela

[ProAc_Fan]

Oh god no Mike please don't bring Jon Hirsh into this discussion. I have seen huge disagreements over the position of Mr. Hirsch re: cables and bi-wiring/bi-amping. All I can state is my opinion and my old Energy C-4's sounded better to me bi-wired than not. As for the technical reasons for this I'll leave that up to the techies!


Mike :smsex:

[GeniX]

uhoh.. *senses potential flamewar*

didnt want a flame war.. just wanted to know if there were any reasons (both techie and non).

[Robh3606]

I am skeptical about it. But I quess I will find out when I try it. If this is true for speaker wire it would have to be true for all wire. If the amp has internal wiring to the output stage it certainly won't be 12ga so the effects of this would be greater inside the amp.

Something to think about????

Rob2:)

[bully]

I have not bi-wired speakers, all my speaker systems are rather pedestrian in nature.
Many of you know, however, that my preference is to only drive one pair of speakers from one stereo amplifier. Since I do enjoy driving multiple pairs of speakers, I usually am using at least two amplifiers.
My experience is that having more 'amp' available is audible at even moderate or low listening levels.
I have what I consider some very fine pieces of gear, but I think my bridged pair of Soundcraftsmen PCR800 (600 watts RMS mono output into 8 ohms, 900 watts RMS into 4 ohms, or 775 watts RMS into 2 ohms) each pushing one of the big JBL CF-150 speaker systems (98dB/watt/meter) creates such a dynamic sonic experience it is palpable. The Telarc 1812 LP was a physical sensation.
I think Thor's experiment is spot on. And I also believe those big gorgeous CV's would only benefit from the push provided by some heavyweight amplification. Gotta think 500 watts per side would be excessive, but I'd like to be there if he ever gets to that point! Yeeee-yoow ;)
Purely subjective, though, even though I'm sure I've heard the difference.

pete

[THOR]

Would my electric bill go up alot using 500 watts per side ;)

[ProAc_Fan]

Probably not Thor how many watts is your hair dryer?




Mike

[Antonio Machado]

experience with bi-wiring: I have a pair of Paradigm Reference Studio 100 v.2 speakers (bi-wirable), I used to listen them with single wire, but when I bi-wire them with no less than the great Transparent Musicwave Ultra bi-wire speaker cable, the improvement was easyly audible. That was a good experience. Now I am considering bi-amping my system letting my actual McCormack DNA-225 dedicated to the woofers of the speakers and a pair of tube amplifiers dedicated to the middle/high of the speakers. Best regards, Antonio Machado.

[poorboy]

hey guy's and girl,

this is very interesting. i personally bi-wire my mission m71, the reason is a follows.

the cables i use are the cat5 type the is 3 cable braided together, i use one strand for my tweeter, and two strands for the woofer. My feeling behind this is that bass takes a lot more of your power and with the 2 thirds of the cable supplying power to the driver i can get more power to the driver. Since my amp is only 40 watts, and my speakers are 89db efficent, i need to be wise with my power.

shibby

[Thatch_Ear]

After I build some SET friendly two ways I am planning on giving the Shahinians an overhaul. I can't have my best down without suffering music withdrawalls! Any way I am going to try both the bi wiring and then skip past the xover sections and use an active crossover to drive 2 amps at their assigned frequencies. That way I can use SS for the power hungry woofers and see if 3.5 watts per channel of SE 6BQ5 can handle the 4 mid/high frequency drivers in each speaker. As it is right now the xover is a single unit and there is only a single set of inputs per speaker.

[Thatch_Ear]

Forgot to mention, if your speakers are set up to bi-wire and you have some gold plated metal plates completing the circuit from one set of BP to another I would consider that using a small piece of your cable might be a better choise. The chances of that being gold plated silver or OFC are pretty low because the bean counters would not allow it.
Thatch