[drummermitchell]

I see the new speaker cables are up on the Bryston site.
What is the difference between Bryston's other 9awg.cable and the new cable(besides the jacket).
Tried finding the thread but .
Must be a Q for James,thanks.

[James Tanner]

Hi Don,

The old cable was a twin lead side by side so given it's different geometry it has different electrical characteristics than the new cable. New Cable is 4 conductors twisted to provide very low self-inductance.

MEMO: To all Bryston Customers
SUBJECT: Bryston SC-4 Speaker Cable

Bryston is pleased to announce the introduction of a Bryston Speaker cable.





The Amplifier/Speaker interface is a 'low impedance' connection. Therefore, in a speaker cable you are looking for low 'self inductance' as opposed to 'low capacitance' required in the RCA or XLR analogue interconnect. For speaker cables we use a stranded 9-gauge linear crystal copper terminated if required with 'Heavily Gold plated' Spade lugs or ‘Expandable Banana’ plugs specially made for Bryston.

A speaker cable should have very low series resistance (R), and low series inductance (L), while shunt capacitance (C), is relatively unimportant in this low impedance, high current application. Shielding is almost a non-issue in speaker cables as signal levels are very large and circuit impedances very low. Speaker cables, however, should be kept as short as possible to minimize power losses and the associated dynamic compression of the music signal. If a choice must be made as to which of your cables should be made longer, always let the additional length be taken up with your interconnects.

The Bryston 9-gauge speaker cable utilizes four multi-strand conductors of OFC copper with advanced insulation. Bryston SC-4 speaker cable provides accurate signal transfer and an ideal match to any Bryston amplifier. It provides power and control for maximum performance especially over long lengths. The SC-4 employs twisted combined opposing conductors (red and white) to positive and (black/gray) to negative for very low self inductance and resistance. Also the cable can easily be configured for utilization in Bi-Wired applications. 


Charcoal jacket; 9.5mm (.375”) diameter
Resistance .0008 ohms/ft                             
Capacitance 70pF/ft                                       
Inductance  .2 uH (microhenrys) /ft
9-gauge
In-wall rated - available in 100 Meter (330 ft) spools

[drummermitchell]

Here we go again,I'm on the phone to Mellissa monday morning.
I have to have 3,RCL,surrounds,hmmmm I'll think about that later.I'll check the price,maybe I can do all 5.I guess that was later .

[95Dyna]

Hi James,

Are these cables pliable?  My current cables are stiff and difficult to work with in the tight space behind my 7's.  It makes a difference as to whether I use spades or bananas.

Thanks.

[James Tanner]

Hi James,

Are these cables pliable?  My current cables are stiff and difficult to work with in the tight space behind my 7's.  It makes a difference as to whether I use spades or bananas.

Thanks.

Hi - I would say 'medium' on the pliable scale.

james

[jneutron]

Charcoal jacket; 9.5mm (.375”) diameter
Resistance .0008 ohms/ft                             
Capacitance 70pF/ft                                       
Inductance  .09 uH (microhenrys) /ft
9-gauge
In-wall rated - available in 100 Meter (330 ft) spools

James,

Are you sure about those measurements?  Something is not correct.

How did you measure the inductance?

Cheers, John

[James Tanner]

James,

Are you sure about those measurements?  Something is not correct.

How did you measure the inductance?

Cheers, John

Hi John,

Got it from the manufacturer - what do you see as an issue and I will ask.

james

[jneutron]

Hi John,

Got it from the manufacturer - what do you see as an issue and I will ask.

james

The LC product is too high.

LC=1034 EDC, L in nH/ft, C in pf/ft, EDC is effective dielectric coefficient.

Your EDC is 6.09.  I'd expect it to be in the 2 to 4 range, depending on the insulation thickness.

Cheers, John

[drummermitchell]

Don't know anything about specs,but if they are a step up from the older version,then were good as I liked the first version of speaker cable.Made the call and ordered 3X2 meters for my fronts.

Electricians here at 6:00PM to connect my 2X240 Torus,I helped out pulling 8/3AWG lumex X2 thru my drop ceiling 50ft.runs+one 20a dedicated line .
TUNES TONIGHT ,.sorry it's been a few weeks without music,3 to be exact.

[Speedskater]

With a effective dielectric coefficient like that, these cables are probably not the best choice for microwave signals.
But then, they are speaker cables.

[jneutron]

With a effective dielectric coefficient like that, these cables are probably not the best choice for microwave signals.
But then, they are speaker cables.

Actually, the EDC has nothing to do with the suitability of a cable over any frequency band, it does not represent any loss term.

It is the simple relationship between the inductance of a cable and the capacitance.  The equation I used is the first thing I use when specs for a cable are given, as sometimes the EDC result can indicate an error in the measurements.  Since inductance is typically the hardest to measure accurately, it is usually the first thing questioned should EDC be wacky.

The velocity of propagation is V = 1/sqr(EDC).  On occasion, someoone's specs will give an EDC less than 1, which is superluminal of course, and obviously in error.

High EDC's generally mean extreme capacitance, or lousy lousy inductance per foot, so high EDC also gives a warning sign.

Cheers, John

[Levi]

Gents, don't get too obsessed about the specs.  We tried lots of cables in different price range and specs means nothing.  Let's let our ears do the judging. 

James, can't wait for new Bryston speaker cables.   

[jneutron]

Gents, don't get too obsessed about the specs.  Let's let our ears do the judging. 

Nobody's obsessing over specs.  The vendor felt it necessary to provide specs, and I have asked him about the accuracy of the numbers being given.

If the numbers are indeed inaccurate, I am very capable of providing guidance so that correct measurements can be taken.

Cheers, John

[Levi]

Got it.  Thanks for the clarification. 

Once you have the correct measurements, where does that take you as far as music goes ? 

Nobody's obsessing over specs.  The vendor felt it necessary to provide specs, and I have asked him about the accuracy of the numbers being given.

If the numbers are indeed inaccurate, I am very capable of providing guidance so that correct measurements can be taken.

Cheers, John

[jneutron]

Got it.  Thanks for the clarification. 

Once you have the correct measurements, where does that take you as far as music goes ? 

An interestingly leading question.

If you have not followed the thread on "path", a quick synopsis..

The characteristic impedance of a speaker cable driving a wildy varying load, will affect the settling time of the signal being delivered to the speaker.  This comes from simple transmission line theory and measurement.  This settling time will swing as much as 10 times the measured capability of humans perception.

This effect is not intuitive to most.

Many misconceptions exist out there, many websites by "technical" people are abysmally incorrect in the theory.

So do the specs matter?  Yes, they do.  Should anyone ignore their ears and go with specs?  No.

Can I categorically state how specific parameters will sound with a specific amp and specific speakers?  No.  That dataset does not yet exist, as prior to my posting the information, the possibility of causation/correlation to the L/C numbers was tenuous; the relationship between cable Z and speaker Z was unknown.

I'll put a graph up in a few, so I can explain a bit more.

edit: already had a graph up of the type I was thinking of, so I'll use it.

This graph depicts the tradeoff between L and C for all cables.  To wit, this particular one is of a coaxial braid pair, so there is no internal inductance to speak of.

http://www.audiocircle.com/image.php?id=11638

The lower the overall energy storage of a cable, the lower and to the left the line gets...the EDC=1 line (dark blue) is lightspeed, nothing can exist below that line.

The higher a cable gets away from the origion, the slower the cable. 

It would "behoove" all to use a graph of this type to locate every cable, and how it sounded, for all speakers.  That is of course, a very long emperical path, I prefer the analytical one of course, so post the technicals so others can do that.


Cheers, John

[Levi]

Been there done that.   

I stopped reading white papers long ago.  For me, it is like reading wikiepedia.  Have you stopped  and asked or measured cables inside your speakers?  What about inside the amps?  Perhaps on an engineering standpoint specs means a lot.  However, we are talking about speaker cables here.  You can have the best looking specs in paper, most expensive terminators, and sounded horrible in real world situations.  My point is just listen to them.

Thanks again John. 

[jneutron]

Been there done that.   

I stopped reading white papers long ago.  For me, it is like reading wikiepedia.

For me, white papers are entertainment. Like watching a train wreck at times.  And, that applies to vendors as well as "engineering types" who are trying to save all from the vendors.

  Have you stopped  and asked or measured cables inside your speakers?

What happens on the other side of the terminals stays on the other side of the terminals.  My analysis shows the interaction of the impedance within to the cable outside.  This is a manu consideration, not a user.  Users should only listen, and can be guided by technical knowledge (should it exist).

What about inside the amps?

My t-line analysis shows how the amp output node is incrementally bumped as a result of the line/load relationship.  Again, that is a vendor concern technically, users would be expected to choose by preference. (edit:  for example, a fast transient will reflect off the load, and when it hits the amp node, the feedback loop will contend with that reflection...if one of the pre's saturate during that bump, how fast will the amp recover?  A technical spec the user cannot consider, yet a situation that a vendor should.)

Perhaps on an engineering standpoint specs means a lot.  However, we are talking about speaker cables here.  You can have the best looking specs in paper and sounded horrible in real world situations.  My point is just listen to them.

Specs mean everything, they will be all encompassing as long as the correct ones are used.  For an end user, they can be meaningless if the interpretation information is lacking.

As I repeat often, what the end user likes is the only important thing.  My goal is to eliminate the disconnect between specs and end use preference. 

Thanks again John.

Never a problem.  Tis a nice discussion.

Cheers, John

[Levi]

Agreed!   

For me, white papers are entertainment. Like watching a train wreck at times.  And, that applies to vendors as well as "engineering types" who are trying to save all from the vendors.
What happens on the other side of the terminals stays on the other side of the terminals.  My analysis shows the interaction of the impedance within to the cable outside.  This is a manu consideration, not a user.  Users should only listen, and can be guided by technical knowledge (should it exist).
My t-line analysis shows how the amp output node is incrementally bumped as a result of the line/load relationship.  Again, that is a vendor concern technically, users would be expected to choose by preference.
Specs mean everything, they will be all encompassing as long as the correct ones are used.  For an end user, they can be meaningless if the interpretation information is lacking.

As I repeat often, what the end user likes is the only important thing.  My goal is to eliminate the disconnect between specs and end use preference. 

Never a problem.  Tis a nice discussion.

Cheers, John

[brucek]

The characteristic impedance of a speaker cable driving a wildy varying load, will affect the settling time of the signal being delivered to the speaker.  This comes from simple transmission line theory and measurement.

Allow me to disagree somewhat. You're applying standard transmission line theory to audio bandwidths. There is no possible transmission line theory that would support any type of reflection on a cable at audio frequencies in any length less than many kilometers. The characteristic impedance of a transmission line is only valid at high frequencies - audio doesn't qualify.

Let me be more specific. The worst case audio frequency of 20Khz has a wavelength of about 15 kilometers in air. Considering the velocity factor of the wire, then a rule of thumb for wire transmission would be about a 10 kilometer wavelength. Pretty long speaker cable. So, as far as standing waves on a few meter piece of cable when we're dealing with a 10 kilometer wavelength, the cable appears as DC. No reflections possible, it won't happen.

It's a very common engineering practice to consider only the DC resistance of a (transmission line) cable when the line is short in comparison with the wavelength of the electrical energy that it conducts. Certainly we would consider a couple meter cable short in comparison to 10 kilometers (at 20Khz audio frequency). In fact, in very short cables, in relation to the wavelength of the signal, the resistance of the line is considered completely insignificant and the energy transferred is considered lossless. This would be the case for an audio interconnect with regard to impedance matching and reflections. It's just not a consideration.

With regard to the L and C of a cable, it's important to consider the interface. In an audio amplifier interfacing to a low impedance load, such as a speaker, other than the simple DCR, the inductance is the most important, while the capacitance can essentially be ignored. The system damping formula is almost exclusively driven by the impedance of the speaker cable, which is a function of its resistance and inductive reactance. Parallel capacitive reactance can be ignored here since this a low impedance connection, so we can essentially disregard it and the bypass reactance it causes as it's too small an effect. Capacitance is only a player in high impedance connections such as interconnects between preamps and power amps, since these are a voltage bridge with a high impedance load and the preamp acting as a voltage source where very little current is being drawn.

Anyway, the inductance spec that James shows is quite good (at the expense of capacitance). Likely a nice speaker cable.

brucek

[jneutron]

Allow me to disagree somewhat. You're applying standard transmission line theory to audio bandwidths. There is no possible transmission line theory that would support any type of reflection on a cable at audio frequencies in any length less than many kilometers. The characteristic impedance of a transmission line is only valid at high frequencies - audio doesn't qualify.

Bruce...approximations taught in undergrad and grad are in general, very good.  However, that said;

Start here:

http://www.audiocircle.com/index.php?topic=87684.60

You need only view my posts to follow, none of the other posts are required for continuity of analysis.
Ask any question you wish.  I will answer.

Anyway, the inductance spec that James shows is quite good (at the expense of capacitance)

Actually, it is impossible for a cylindrical single wire pair to have that little inductance, no matter what is done...twisting specifically.  That is actually what spurred my question.

Cheers, John