Bi-Wiring, what exactly is it doing?

CoolJazz

Oooo...unless my mind is deceiving my eyes (and my ears) that guy in the background of that movie poster looks just like Kevin's old avatar! Freakyyyy.....

Bring back your old avatar Kevin. See if I'm not right!!

CJ

CoolJazz

kevintomb wrote: »

Maybe you have me confused with someone else?

I have been working in movies for several decades. Not the same guy

Oh....come now Kevin. Don't be shy. The real you is slightly scary but we'll survive....

The movie version of Kevintomb...


The original Kevintomb....


See....I think there is certainly some reason to believe Kevin was in that movie!! Being in the witness protection program can only change just so much....

CJ

skrol

On the topic of bi-wiring... I have considered this from an EE standpoint.

1) You have a source which is producing the full audio spectrum.

2) You have one wire pair, with its own reactive impedance (little RLC networks), subjected to the high frequency signal (mid and tweeter signal). The lows are blocked by the high impedance of the crossover at these frequencies.

3) You have the other wire pair, with its own reactive impedance (little RLC networks), subjected to the low frequency signal (woofer signal). The highs are blocked by the high impedance of the crossover at these frequencies.

4) From a purely resistive standpoint, you have increased the effective wire diameter (lower wire resistance). You also have two frequency reactive impedances in parallel but operating at different frequencies. The circuit gets quite complicated especially at the crossover frequency.

5) Compare this to a single pair in which all frequencies pass through the frequency reactive impedance (little RLC networks) of the wire.

I have not tried it yet but I can see that there may be an advantage to bi-wiring for some of the same reasons that we have 2 and 3 way speakers. The question is. how much difference does it make?

Typically folks say to use the same type of wire for the highs as the lows. Perhaps there is an argument against this? Would it be better to use a wire with lower impedance at high frequency for the high frequency signal and vice versa for the low?

This could be a whole new marketing strategy for speaker wire manufactures.

BlueFox

I believe both pair of wires have the same frequencies between the amps and speakers. The cross overs in the speakers then separate out the frequencies they need.

PSOVLSK

xcapri79 wrote: »

...No we should follow our informed brain. If one better understands the engineering and science behind audio signal transfer then one would look for good quality inexpensive cables and not need to spend substantial money on exotic cables...

How can there be "good quality inexpensive cables" if cables don't matter?

BlueFox

PSOVLSK wrote: »

How can there be "good quality inexpensive cables" if cables don't matter?

I suspect he means things like good quality copper, good connectors, good insulation, and good construction.

Of course, as you say, these things do matter, and there is no upper limit on the performance one can achieve with better and better cables.

F1nut

BlueFox wrote: »

I believe both pair of wires have the same frequencies between the amps and speakers. The cross overs in the speakers then separate out the frequencies they need.

Correct.

tonyb

For the most part, a bi-wired set of speaker cables from most any brand runs the same gauge for both top and bottom. I have seen some that will run a smaller gauge on top but I don't see the benefit there.

I think where some may run into weird differences is when they try bi-wiring with 2 separate brands of cables, both with different measurements in their build quality.

CoolJazz

BlueFox wrote: »

I believe both pair of wires have the same frequencies between the amps and speakers. The cross overs in the speakers then separate out the frequencies they need.

Same frequencies, but when the impedance climbs from the crossover, the current is what is effected and where the differences may start to occur.

CJ

ukcolin99

Thanks to everyone for their input, I started this thread with a quote from the Polk Quick Start Guide I received with my new 705's, refurbished 703's & new 706c. Here's a little more from the one page (in English) document: "and one set of (usually heavier gauge) wires to the lower terminals." Surely Polk would not include the statement (my words) "Bi-wire is better & connect heavier gauge to lower terminal" if there was no benefit?

afterburnt

Bratwurst? As usual I cheaped out and used a can of Vienna sausages %^)

gp4jesus

F1nut wrote: »

I cannot understand why some folks think that cables are somehow not an integral part of the rig and skimp on them.

+1 w/in certain limits. I can't let this continue w/saying the same about the room & passive XO components.

I scratch my head every time someone "hawks" about cables, some VERY $y, w/the original nickle-dime passive XO in the chain. Anyone remember the $8K cable thread?!

Or replacing anything & everything to correct "brightness*" because the room has either uncovered hardwood or tile flooring, an undraped 6, 8, or 9' patio door, or, perish the thought, both. My ears thinking about that!

I have more supportive, but moderate stuff to add about bi-wiring including, gasp(!), the results of same for a pair of dual driver subs.

Tony

gp4jesus

nspindel wrote: »

How'd I know this thread would turn into an argument about cables?

They ALWAYS do!! Cables & ICs: the most controversial topic in AV.

ZLTFUL

gp4jesus wrote: »

They ALWAYS do!! Cables & ICs: the most controversial topic in AV.

And the amusing part is it always the naysayers telling the believers how wrong they are to spend THEIR money however they choose.

If one were to use that logic, then you could say that @xcapri79 has drank the McIntosh Kool-Aid because he believes they are the best product out there.
But you won't ever hear me tell him that because it is his money to spend however he sees fit. But he will jump right in and tell someone they are stupid because they want to experiment with different cables. Seems like a real time double standard emergency we have here.

F1nut

I mean an audio cable that advertises its directionality is just nonsense.

There's nothing about a ground and/or shield drain that is nonsense. Geesh, you don't even know that!?!

BlueFox

While your post about directionality might be accurate, without posting a link so that it can be read in context, the post is not very useful. It could be completely made up.

However, based on what was posted, it does seem reasonable that a cable could be better for audio in one direction versus the other. Whether it would be worth paying extra for is another matter.

WilliamM2

BlueFox wrote: »

While your post about directionality might be accurate, without posting a link so that it can be read in context, the post is not very useful. It could be completely made up.

Bottom of page 10:

http://www.audioquest.com/pdfs/aq_cable_theory.pdf

And I agree, it sounds like they just made most of it up.

gp4jesus

Nightfall wrote: »

Why trust your ears? Useless things they are, right?

What a novel concept?!

PSOVLSK

afterburnt wrote: »

Bratwurst? As usual I cheaped out and used a can of Vienna sausages %^)

Underrated

My question to the cable naysayers: Do you really think there could be a multi-million dollar industry that's been around for years if their products didn't work? Seriously??? Multiple companies can sell products that do absolutely nothing and somehow they stay in business?

I have lots of other very simple questions, but I'll start here.

gp4jesus

In my experience lower impedance and/or more reactive loads "like" heavier wire.

nbrowser wrote: »

RTiA7, HK 3490 standard wired... ...two pieces of 12 gauge... ...hear a difference, better attack; bit better bass

Not surprising. 4 ohms below 125hz - w/lower impedance, size (gage) matters more.

nbrowser wrote: »

better top end.

? How so?

nbrowser wrote: »

Second power source HCA-1200II... ...more noticeable... ...low end gained some weight over single wiring... ...it IS power dependent as well.

Again not surprising.
The P'sound thumps the HK w/juice! Higher current, more (8ohm) power & 4 ohm rating w/even more power. Important points given 4 ohms below 125hz

CoolJazz

xcapri79 wrote: »

With an unbalanced RCA cable, the shield with or without a drain wire is typically connected to the RCA sleeve on both ends which also carries the signal on both ends. The sleeve on both ends is connected to a grounded chassis. This actually forms a Faraday cage around the RCA tip (hot) connection to reduce RF noise. There is really no need for an extra drain wire connection. Connecting the shield on one end can increase RF noise by acting as an antenna.

A terrible concept! Unbalanced done with coaxial style cable is common maybe but not the best way.

It should have two conductors internally. One for hot and one for return. The shield should be used as a drain. It should be connected only to the output end, as it's lowest impedance and therefore least likely to have the drained signal impressed upon the audio.

Unbalanced done this way can be successful in intensely hostile for audio environments.

Sometimes you'll see the foil used with a drain wire physically adjacent to the foil, to do the same thing. But then many find that technique of Belden's to simply not yield the best audio results. Even though it fits with their 'RLC is the only thing that matters' beliefs.



The copy and paste answers fail yet again when measured against the real world.

CJ

WilliamM2

PSOVLSK wrote: »

My question to the cable naysayers: Do you really think there could be a multi-million dollar industry that's been around for years if their products didn't work? Seriously??? Multiple companies can sell products that do absolutely nothing and somehow they stay in business?

I have lots of other very simple questions, but I'll start here.

Seriously? Apparently you haven't heard of homeopathy, a 7 billion dollar a year industry. Magnet therapy alone accounts for over 1.5 billion. People believe all kinds of nonsense.

http://nationalpainreport.com/study-finds-copper-magnetic-therapy-waste-money-8821693.html

gp4jesus

Hard to deny Psovlsk's point. I completely agree w/ Nbrowser: try it! Have fun along the way.

I bi-wired a pair of dual driver subs by cutting the original single 10 ga run in half NOT EXPECTING a change! Had to drop the LP drive several dB - EVERYTHING sounded fat!

So bi wire naysayers, mo' bigga, mo' louder when it comes low impedance (3 ohms!) bass sources. I'm sure that applies up to top of the bass register, say ~500hz.

DarqueKnight

cbridle wrote: »

The Polk Quick Start Guide that came with my 703's, 705's & 706 states "Bi-Wiring can provide noticeable improvements in the overall transparency of your loudspeakers.

If the speakers are designed so that best performance is achieved if the high frequency and low frequency parts of the crossover are powered from separate wire branches, and if your gear is resolving enough, then the lowering of electrical noise due to bi-wiring can result in audible improvements in sound quality.

It is similar to the concept of running dedicated AC circuits in order to reduce the noise from devices on one circuit affecting devices on another circuit. All of the AC circuits in a house are fed from the same tap from the power company, but running separate circuit lines from the same current source results in noise isolation benefits. Similarly, isolating low power treble signals from higher power, higher noise content bass and midrange signals can result in cleaner, more detailed sound.

Running a single pair of speaker cables to a speaker results in the amp "seeing" a single circuit with a single complex load at the end. Running a pair of speaker cables to the low frequency section of the speaker and a second pair of cables to the high frequency section results in the amp "seeing" two different circuits with two different complex load at each circuit end.

kevintomb wrote: »

To answer the first bolded part.
A cable has NO soundstage at all. Nor separation of instruments, placement etc. '
It conducts an alternating current signal.
It will either conduct the signal fully intact or degrade it some minimal amount.

The rest is sales talk.

You are correct that a cable, or any other audio component does not have a sound stage. Sound stage is a psychoacoustic phenomenon that occurs in the brain.

However, the electrical performance of a cable can alter the stereophonic perception of sound stage, imaging, and image weight.

kevintomb wrote: »

All facets of alternating current can be fully measured, at ALL levels down to below human hearing.

Sorry it really is that simple.

There is a lot that is unknown pertaining to how to correlate measurements to perceived audio performance.

If cable science were really that simple, telecom companies would not have invested billions over decades in cable research. Bear in mind that telco systems primarily transmit a very band-limited range of frequencies for voice. They are not primarily concerned with transmitting complex a complex signal like music. Nevertheless, telco research has resulted in cables with different dielectric properties, different twist geometries, and different copper formulations in order to optimize voice signal transmission. AT&T at one time owned a cable factory in Norcross, Georgia that manufactured cables to their specifications. If "wire was wire", they just would have bought bulk generic cable from outside vendors.

kevintomb wrote: »

Not everything alters the sound. That is a myth also.

Not everything alters the perceived sound, but every thing has a measurable effect on the electrical signal passing through it.

kevintomb wrote: »

SOME and even many things alter the sound true, but not truly everything.

The guys that design all this stuff we listen to, truly know what matters or does not, not the marketing claims.

Well, the OP started off with a quote from his speaker manufacturer that recommended bi-wiring. Last time I checked, Polk doesn't sell speaker cable. Therefore, if Polk advises that their speakers may sound better with bi-wiring, I am inclined that this may be true in certain situations.

cbridle wrote: »

Surely Polk would not include the statement (my words) "Bi-wire is better & connect heavier gauge to lower terminal" if there was no benefit?

No, they would not.

WilliamM2 wrote: »

Bottom of page 10:

http://www.audioquest.com/pdfs/aq_cable_theory.pdf

And I agree, it sounds like they just made most of it up.

Copper wire, depending on its composition and on how it is drawn, can have different mechanical and electrical properties (directionality) in one direction compared to the other.

The concepts discussed in the AudioQuest Cable Theory paper are backed by solid science. Again, I would refer you to telco research, most notably that of AT&T Bell Labs, on the subjects of dielectric absorption, twist geometry, copper purity, and directionality. If you go to the IEEE Xplore website, you can search on these key words and find references to many peer-reviewed engineering journal papers on these topics. For example:

"Murray, H., "Characterization of copper-beryllium alloy C17510," Fusion Engineering, 1991. Proceedings., 14th IEEE/NPSS Symposium on , vol., no., pp.280,283 vol.1, 30 Sep-3 Oct 1991"

Abstract:

"The BPX (Burning Plasma Experiment) toroidal field coil conductor is fabricated from plates of C17510, a copper-beryllium alloy. Results of tensile characterizations of this alloy at room temperature and liquid nitrogen (IN2) are presented with room temperature fatigue results at R=0.05. The R=0.05 characterization data represent the constraint on the design curve of stress amplitude versus cycles-to-failure. Data are also presented from precision, four-wire electrical conductivity measurements. These measurements include samples of material extracted from key process steps of the C17510 manufacture and span the temperature range of IN2 to 300 K in increments of 25 K. The grain structure of the material is also reported for key process steps and material orientations. The directionality of key properties is discussed."

By the way, the electrical and mechanical properties of beryllium copper, as explained in the paper cited above, provide a scientific basis for why higher-end audiophile grade AC receptacles, such as the PS Audio Power Port Premier and Oyaide R1, use beryllium copper rather than the ordinary tough pitch copper used in regular residential receptacles.

ZLTFUL

xcapri79 wrote: »

I mean it is quite hilarious to an electrical engineer.

So you're an electrical engineer? Because I know of several who think the opposite or your blathering idiocy.
And yet you still dance around the prime question...why are you so hellbent on "saving" other people from spending *their* money however *they* see fit?
Are you a crusader? Are you everyone's banker?

In that case, why don't you STFU when the adult folks are speaking. Oh...look...there is a real electrical engineer just up there categorically shooting holes in your "claims". But you will ignore them just as you have ignored my question over and over.
Fortunately, the vast majority of the folks here can see your ignorant rhetoric.

F1nut

That said there are some here that buy into that explanation and believe a bag of charcoal on top of a speaker can improve its sound.

Once again, your reading comprehension needs serious work. The member who posted about the coal states that it did not make a difference when placed on top of the speakers.

DarqueKnight

xcapri79 wrote: »

Running a single pair of speaker cables to a speaker results in the amp "seeing" a single circuit with a single complex load at the end. Running a pair of speaker cables to the low frequency section of the speaker and a second pair of cables to the high frequency section results in the amp "seeing" two different circuits with two different complex load at each circuit end.

The amp doesn't keep track of separate wires. The amp sees the pretty much same complex load with two connections at the same amp terminals as it sees for a single connection at the same amp terminals as long as sufficiently large conductors are used.

I didn't say the amp keeps track of separate wires. I said the amp (source) becomes connected to two different complex loads with two different impedance characteristics when you bi-amp. In other words, one circuit loop with one impedance characteristic is replaced with two circuit loops with two different complex impedance characteristics. I further said that such isolation can reduce electrical noise just similar to putting different household electrical devices on different AC circuit branches.

xcapri79 wrote: »

The amp is a time varying multi-frequency source and the currents from the amplifier will flow into the speaker load in accordance with Ohm's law, and Kirchoff's current and voltage laws. The speaker essentially operates based on Faraday's law of induction. All these are well understood scientific and engineering concepts.

Again, my point is that splitting a complex, reactive, electrical load into two parts and placing each part on a separate circuit branch is not electrically identical to the same load combined on a single circuit branch.

xcapri79 wrote: »

Telco companies are running wires over hundreds of feet if not miles and are involved in numerous commercial, industrial and military applications. The engineering design requirements are different for those applications vs consumer audio interconnects. It is ridiculous to extrapolate extreme properties, requirements and applications to audio equipment based on performance.

Actually, the signal integrity requirements between telco audio transmission and stereophonic audio are very similar. I have some knowledge of the topic because I spent 12 years in telco engineering and 4 years in telco R&D.

xcapri79 wrote: »

The science is misapplied and pseudo-science created to market esoteric cables because they earn tremendous profits.

Yes, I agree that some cable manufacturer's claims are not grounded in scientific validity. There are scam artists in every field of commerce. However, you make yourself look like someone on a hysterical witch hunt by claiming that all high performance audio cable manufacturers are peddling snake oil.

tonyb

You guys are wasting your breath. The only thing you'll hear from X is bogus reasons why he WON'T try anything. Which imho, is ok if he's happy where he's at in his musical enjoyment.

However, others may not be, and that's the whole point of discussing audio related topics or to further your basic knowledge of all things audio.

Which then begs to question, why are you even here X ? You seem satisfied with where your at, obviously you know more than others....in your own mind anyway, whats the point of your membership then ?

skrol

F1nut wrote: »

BlueFox wrote: »

I believe both pair of wires have the same frequencies between the amps and speakers. The cross overs in the speakers then separate out the frequencies they need.

Correct.

Yes, but wouldn't each pair see a different load impedance given the same frequency (except at fc)? Yes, the same signal is applied to both pairs but the signal flow is going to be different through each pair as dictated by the reactive impedance of the high frequency network and the low frequency networks in crossover and the drivers themselves.

As the wire pairs are an RLC network, you have an RLC network for the high pair in parallel with the mid and tweeter XO and mid and tweeter drivers. Then you have an RLC network for the low pair in parallel with the woofer XO and the woofer driver. The question seems to be, is there a change in the signal quality (shape and/or amplitude at various frequencies) due to the cables or is it simply a matter of reduced impedance for the signal going to the highs and to the lows?

I should try to simulate the difference between single and bi-wiring in PSpice, though I haven't not had much success in finding such differences.

skrol

I think DarqueKnight is explaining what I am trying to say a little better.