[drummermitchell]

I wonder how dramatic(sound wise,control)the difference from a 1.5 metre speaker cable to say a 4 metre cable.
I was thinking of MOVING ,all of my racks to the side and just having three
main speakers in front with the amps.
It would definately clean up the front,I did move my speakers in about 3 ft.from
where they were(close to the side walls and about the same from the back.
Main concern is speaker cable length.
I'd hate to move all my gear and spend more coin on cables and find that the
sound is worse with the longer cables.
What would I lose going to longer lengths,would it be a dramatic difference,Thanks guys.

[James Tanner]

The length and resistance of the loud-speaker cable in your audio/video system is very important. In fact, any speaker cable is a compromise and the shorter you make your speaker cable the more accurate the sonic result.

Keeping speaker cables as short as possible is essential for maintaining good (damping) control over the loudspeaker drivers. Music is a dynamic 'transient' (stopping and starting) condition and the better the amplifier can control the motion of the drivers in your loudspeakers the better the performance. The normally extremely low output impedance of the power amplifier will be compromised by any addition of 'series resistance' associated with speaker cables. Therefore, no cables (as in powered speakers) are best followed by keeping the speaker cables as short as possible.

Most loudspeakers have impedance curves which will vary all over the map with frequency but this does not mean that adding a small series resistance due to loudspeaker cable is unimportant. In fact, if you add some small resistance between the amplifier and the speaker, you will create an interesting result. The loudspeaker's frequency response will start to vary directly as its own impedance! The magnitude of this effect increases directly with the magnitude of the series resistance added. So what you can end up with is a frequency response from your speaker which is a direct mirror of the impedance curve of your loudspeaker. This undesirable effect can be minimized with short, low resistance cables and low output impedance amplifiers (no tubes please). The output impedance of any decent modern power amp will be practically zero ohms (Bryston amplifiers are typically .01 ohms). To optimize the damping factor (ratio of speaker impedance over amplifier output impedance plus speaker cable impedance), any resistance between the speaker and the amp is undesirable. If we had a perfect amp with an output impedance of zero ohms and a perfect speaker cable with a series resistance of zero ohms then the damping factor would be infinite. Note: In this case the damping factor would be infinite regardless of speaker impedance (something, even if it changes, divided by nothing is always infinity).

At the other extreme, power loss in your speaker cable contributes to audible dynamic compression because:

Cable Power loss = Current SQUARED X Resistance of speaker cables.

On dynamic peaks, output current can be in the 'tens of amperes'. That squared, times what might seem an insignificant amount of cable resistance can cause significant power loss.

This may explain to some degree why some people hear substantial quality increases in their systems when they bi-wire or tri-wire while others claim little or no improvement. In some cases the extra set of speaker wires would significantly reduce the resistance (and improve the damping factor) between the amplifier and the loudspeakers, especially in long runs. With the advent of multi-channel audio systems utilizing rear/back channels usually positioned 20 to 30 or more feet away from the amplifiers this lack of control becomes a serious issue. The Bryston PowerPac Series of amplifiers are an attempt to minimize this problem by allowing the amplifier to be placed adjacent to each loudspeaker or attached directly to it (ex: PMC loudspeaker) using long interconnects (preferably balanced). By the way, the reason that cable length is relatively unimportant for component (Preamp to Amp) interconnects is that the magnitude of signal current in the conductors of interconnect cables is so small the power loss is insignificant.

You must always try to preserve the dynamic integrity of the recording so reducing the resistance of your loudspeaker cable is one giant step it the right direction.

james

[drummermitchell]

Thanks James,I just realized  ,I can keep my 1.5 speaker cables and order
some longer balanced interconnects.Frig,now I need a new 55"lcd TV as my
52" can't mount on the wall.Dang it,it just breaks me heart,I guess I'll have to
let the wife know , .

[redbook]

Yes, I know that James is right . I have always kept my speaker lines to six feet. The amp is center located and the speakers therefore are about eleven feet apart. For me ,this works in my set up. The cables are Audioquest CV-4, custom cut and terminated with expanding bannana plugs.

[vegasdave]

Same here redbook. I use 10 gauge Belden, bare wire.

[Mad Mr H]

In my cinema setup

The front L C R are all Bi Amp with 3 foot long Kimber Select KS3038

When it comes to the rears I have a pair of 35 foot long !!! speaker cables - My Bad    - Kimber Select at break the bank prices 

2ch uses tri amp with 2 pairs Kimber Select KS3038 and one pair of Kimber Monocle XL for the bass.


Thisis one reason I keep the kit at the front near main speakers.........In time, one day in the cinema room I will move the rear amps next to the speakers.

[95Dyna]

Hi James,

Recognizing the impracticality for many of us to keep SC's at 1 metre or less is there an optimal point beyond which one would begin to see significant degradation.  I can't go shorter than 2.75m (9ft) to stage right but only need 6ft to the left (running from 7Bsq to 5 ohms nominal).

Bill

[James Tanner]

Hi James,

Recognizing the impracticality for many of us to keep SC's at 1 metre or less is there an optimal point beyond which one would begin to see significant degradation.  I can't go shorter than 2.75m (9ft) to stage right but only need 6ft to the left (running from 7Bsq to 5 ohms nominal).

Bill

Hi Bill,


Increasing the gauge (I use 9.5) and bywiring helps.  I would say a couple of meters is not much of an issue.  I typically use 1 meter lengths.

james

[vegasdave]

How does biwiring help?

[James Tanner]

How does biwiring help?

It quarters the resistance.

james

[gerald porzio]

Once the proper guage cable is used for a given length, any quartering or further reduction of the cable resistance is theoretical at best.

[rmurray]

I have never understood the bi-wire deal! If it is only the matter of reducing resistance then why not opt for larger guages? I could go to more strands of the same wire product, right?! I have jbl's of the old school single post connections. I have noted that some other hi class speakers like Jimlab and Sonus faber have stuck with the regular arrangement. I thought it had to due with the type of crossovers although I have never read any rational to really support the bi-wire thing. (other than it's only a marketing scam.) Please shed some light on this; I have other audio friends that share the same quest. Meanwhile James has made the greater sense to my way of thinking. Thanks , it helps alot in this area of learning   RMURRAY.   

[James Tanner]

Hi rmurray:

Correct a higher gauge would do the same thing.  I was referring to using two runs of the same gauge as opposed to one run of the same gauge.

Here's where it gets tricky - many speaker designers I know say that the biwire thing (assuming adequate gauge for the load and powerful enough amp) is simply a marketing ploy. Others claim that there is some advantage to bi-wiring over simple reduction of resistance. 

The theory goes something like this:  in a two way speaker with a single set of wires and a single amplifier feeding the speaker the amplifier driving the speaker is affected by the 'none linear impedance' of the woofer. The back EMF force (a speaker is a motor) can create some distortion in the amplifier as a result of this back EMF. So that same distortion gets fed to the tweeter because it is in series with the woofer through the crossover.

In a bi-wire configuration where you have independent cable connectors and total separation of the crossover between the woofer and the tweeter the distortion from the non linear impedance of the woofer cannot affect the tweeter because it would have to travel back down the woofer cables, through the amp and back up through the tweeter cables.  It can not do this because of the very low output impedances of most good amplifiers. You can take this one step further and use two amplifiers one for the woofer and one for the tweeter!

So that's what the experts tell me -as always = listen for yourself.

[rmurray]

Thankyou Mr. Tanner. That has made sense to me (finally). Does this idea hold any merit ,technically, regarding a threeway or more system I wonder?   

[James Tanner]

I would assume so because the bigger the driver the bigger the motor?

james

[redbook]

Well that answers my questions too,.........  redbook.

[gerald porzio]

Altho my Thiel CS 7.2 aren't biwireable, with 12 ft. of speaker cable going from 10Ga. to 7Ga. (doubling up the 10Ga.), there was no audible difference. Using an amp with a low output impedence (high damping factor) effectively prevents with any EMF from affecting the tweeter. Since tweeters have significantly less mass & movement than woofers, they require significantly less damping factor.

[95Dyna]

Hi rmurray:

Correct a higher gauge would do the same thing.  I was referring to using two runs of the same gauge as opposed to one run of the same gauge.

Here's where it gets tricky - many speaker designers I know say that the biwire thing (assuming adequate gauge for the load and powerful enough amp) is simply a marketing ploy. Others claim that there is some advantage to bi-wiring over simple reduction of resistance. 

The theory goes something like this:  in a two way speaker with a single set of wires and a single amplifier feeding the speaker the amplifier driving the speaker is affected by the 'none linear impedance' of the woofer. The back EMF force (a speaker is a motor) can create some distortion in the amplifier as a result of this back EMF. So that same distortion gets fed to the tweeter because it is in series with the woofer through the crossover.

In a bi-wire configuration where you have independent cable connectors and total separation of the crossover between the woofer and the tweeter the distortion from the non linear impedance of the woofer cannot affect the tweeter because it would have to travel back down the woofer cables, through the amp and back up through the tweeter cables.  It can not do this because of the very low output impedances of most good amplifiers. You can take this one step further and use two amplifiers one for the woofer and one for the tweeter!

So that's what the experts tell me -as always = listen for yourself.

James,

How does using two discreet runs to each speaker compare to using high quality cables that are a single pair at the amp end and 2 pair at the speaker end.  With the 7B's wouldn't you have to bi-wire this way due to the lack of a second output?

[James Tanner]

james

[95Dyna]

OK, so you piggy back on the one pair of outputs with bananas using 2 separate cables.  How does this compare to using a single bi-wire cable with two connectors at the amp end and 4 at the speaker in terms of lowering cable induced impedence.  So many of the prominent cable manufacturers are selling these bi-wire cables claiming the performance advantages discussed above.