The effect of cables - A sane debate

[jls001]

After combining two runs (different RCA plugs - REAN) I measure 470 pF. I would expect 240-260 pF at most.

As I had doubts about my measurements I took apart one cable assembly and measured the capacitance of the component parts just to reconfirm.

The four RCA splitters measured 10.7, 15.3, 8.3 and 8.1 pF.

The four Belden 8402 cables with the RCA plugs measured 224, 215, 217 and 206 pF.

Adding up, one cable assembly measures 460 pF and the other about 444 pF. So I guess my earlier measurement wasn't off.

I feel a sense of upper highs being slightly rolled off, probably owing to capacitance doubling. Time to make a new EQ curve for foobar.

 

[vnavin]

Moderator's note

Again the cable debate begins. Some other viewpoints from other forums for all to consider,

Audiophile cables, an interesting question.

Do 'High-End' Audio cables matter?

This will be a never ending debate for millenias.............

BTW, 2 weeks ago FM sprivous was at home with a 'Monster cable' costing Rs.1800/- . I really could not make out the difference between that and my Rs.28/- cable sound quality other than the cost.

Kindly note:
This is already a long thread.
My comments are not in continuation to any earlier discussion going on but starts as a reply to the thread heading and in response to the content in post #1.

So short answer to the question on hand:
Do 'High End Cables Matter?
No, Not at all.

But my system does respond positively to better cables.
That could be since the amplifier design is could be at fault.

But my amplifier is of a very trusted brand!
In support I say: Speaker impedance varies up to +400% to -100% from its nominal value. If the amplifier design is unable to cope with such large impedance then of course it will respond to cable impedance variation. But then the amplifier cannot be trusted to deliver power faithfully corresponding to the input signal and input signal only.

Regards,

Ravindra.

Hi
Good to hear from you but I have a digferent opinion as cables are puerly engineering to achive the desired goal.
Regards
Navin

 

[Ravindra Desai]

Hi
Good to hear from you but I have a digferent opinion as cables are puerly engineering to achive the desired goal.
Regards
Navin

Where is the supporting math (from ANY manufacturer. No videos or sound comparison please. Only Math!)

Also, would you rather have a system that works nicely with ANY cables or do you want your system to change its sound profile with change in cables?

Regards,

Ravindra Desai.

 

[jls001]

Where is the supporting math (from ANY manufacturer. No videos or sound comparison please. Only Math!)

Is there a universally accepted mathematical model or a transmission line model for a cable that correlates the subjective impressions of listeners to the quantum of specific electrical and physical parameters?

 

[captrajesh]

@Ravindra Desai, all the theoretical talk of Amplifier design fault etc. etc. is of little use. What matters is, what's happening on ground. I'd be glad to know of your experiences with cables and amplifier of "good design" (if any)

 

[Kannan]

Where is the supporting math (from ANY manufacturer. No videos or sound comparison please. Only Math!)

Also, would you rather have a system that works nicely with ANY cables or do you want your system to change its sound profile with change in cables?

Regards,

Ravindra Desai.

Absolutely....
Amplifier design is not rocket science and most good brands I am sure offer a good design.

My layman understanding is that there is a minimum level of quality requirement where the need is to minimize interference and noise and have the lowest capacitance value with low level signals.
Also the connector quality matters for a strong connection to minimize signal loss.
Any degradation in low level signal is bound to get magnified at the amplifier stage.
With speaker cable, I think 16awg is more than enough. Decent insulation. Material is need basis...tinned copper for coastal areas is recommended. Some prefer silver though very expensive.

However my suggestion is to lower the overall system noise at the power stage. This has worked the best for me.

 

[Ravindra Desai]

Is there a universally accepted mathematical model or a transmission line model for a cable that correlates the subjective impressions of listeners to the quantum of specific electrical and physical parameters?

'Subjective' is the term that is worrying.
Kindly show me the link to that model.
I would like to understand how that model can generalize the input impedance of ANY amplifier.

If a DIY cable experiment yields favorable results to different users irrespective of their amps, source and speakers and yields great sonic values at very modest costs then its a great effort and worth recognizing and practicing.

Of-cource. I agree, provided it results in improvement universally rather that with isolated individuals.

@Ravindra Desai, all the theoretical talk of Amplifier design fault etc. etc. is of little use. What matters is, what's happening on ground. I'd be glad to know of your experiences with cables and amplifier of "good design" (if any)

A couple of us conducted a cable test with a NAD amplifier in LaCozy, Mumbai, a while back.
Cables ranged from DIY to very expensive ones. Of cource we did not use any low grade, corroded, alluminium cables to check for de-gradation.
There was absolutely no change in perceived audio quality what so ever.

I have my own amplifier designs that I can lend for experimentation that works just as good with ANY cables.

On the other hand, let me know of a cable that I can use with my system or a cable guideline that I can follow and I will do so and report back.

Absolutely....
Amplifier design is not rocket science and most good brands I am sure offer a good design.

But there is a minimum level of quality requirement where the need is to minimize interference and noise and have the lowest capacitance value with low level signals.
Also the connector quality matters for a strong connection to minimize signal loss.
Any degradation in low level signal is bound to get magnified at the amplifier stage.
With speaker cable, I think 16awg is more than enough. Decent insulation. Material is need basis...tinned copper for coastal areas is recommended. Some prefer silver though very expensive.

However my suggestion is to lower the overall system noise at the power stage. This has worked the best for me.

I agree to everything that you have said and it forms the basis of basics to be followed when wiring up a system.
Most Basic cables comply to these guidelines.

Regards,

Ravindra.

 

[Kannan]

As regard to connectors, I have used quite a few types.
For DIY ery guys like me who keep fiddling, the crocodile grip type (I mean very strong push in push out type of connectors) are not warranted as frequent removal can cause damage.

The ones I like most are the star flex type connectors which give a strong grip, but are easy to remove. The best I have used are the screw lock connectors, where you screw down the top and it grips to the input connector. For removal you just need to unlock.

The example of screw lock connector found in a reference MX cable that I have

 

[keith_correa]

Is there a universally accepted mathematical model or a transmission line model for a cable that correlates the subjective impressions of listeners to the quantum of specific electrical and physical parameters?

Don't know about universal acceptance but we can model this in SPICE. You should measure source, driver and cable impedance, capacitance and inductance and use those values in the model. Then check frequency and phase shift.

 

[jls001]

'Subjective' is the term that is worrying.
Kindly show me the link to that model.
I would like to understand how that model can generalize the input impedance of ANY amplifier.

The entire human experience of enjoying audio is subjective. So it need not be worrying when people describe their audio experiences in subjective, perhaps even vague, terms. What should be worrying is when we assume or believe that we know exactly how the three parameters of resistance, capacitance and inductance, or their derivative parameters, behave to cause the subjective responses. Sure, science knows at the basic level but that's about it.

I'm not clear why you're asking me for a model. I myself was asking if there's such a model since you asked for "math only".

 

[jls001]

Don't know about universal acceptance but we can model this in SPICE. You should measure source, driver and cable impedance, capacitance and inductance and use those values in the model. Then check frequency and phase shift.

Frequency and phase responses don't describe all our subjective experiences. There's room for "art" in audio design, I feel.

 

[Kannan]

Don't know about universal acceptance but we can model this in SPICE. You should measure source, driver and cable impedance, capacitance and inductance and use those values in the model. Then check frequency and phase shift.

I have experienced many a times in car audio that even after perfect installation with good equipment, the RTA curve can be haywire due to poor acoustics and speaker driver placement.

Even after tuning with DSP using mic and softwares like REW and achieving the best measured flat response, it does not sound good to the ears.
It is also true that most do not like flat response and do like a blip here and there which I think is what is termed as house curves of various types.

I personally don't like applying any type of EQ. It also does not sound good to my ears.
My reasoning is that if you get a good source quality, then fiddling with EQ spoils the originality of the signal as we are compensating for the deficiency in room acoustics by adjusting the octave character of the music.

Music interpretation is so very personal and subjective, that there are bound to be vagaries.
So those on budgets (high or low) should be careful in allocating the percentages of that budget, and cables should be the least of that, as in my experience, they have the most diminishing value as you scale up.

But for the unintended with no budget constrain, sky is the limit.

However experiments like these (the double interconnects) are truly interesting, setting aside the scientific part. Since there is a huge cost benefit, if it works nothing like that.
That is why forums like hifivision are a great place to be in to read, interact, experiment and share.

Happy listening!

 

[keith_correa]

Frequency and phase responses don't describe all our subjective experiences. There's room for "art" in audio design, I feel.

To those that believe in this, maybe.

Art is not taking a brush, making a stroke and then seeing if it looks good or not. There is a thought and specific meaning behind every stroke. Without that everything is a shot in the dark.

I hear talk (loose?) of capacitance, rolled off highs etc and that too from people who have the equipment to measure/model. The values are invariable for the source and driver so set that in stone. They are variable only for the cables so why not measure, model the souce, the driver and cable and then determine a bottom threshold below which these values are unacceptable. Then don't sweat the individual cable parameter values just as long as these values are above your bottom threshold values.

 

[Ravindra Desai]

Don't know about universal acceptance but we can model this in SPICE. You should measure source, driver and cable impedance, capacitance and inductance and use those values in the model. Then check frequency and phase shift.

Hello,

Here is my math model:

If you will all agree:
Cable has an effect of low pass filter. Its effect will be noticiable in high frequencies.
The cable resistance and the cable inductance forms the series arm of this low pass filter and the cable capacitance forms the parallel arm of the low pass filter.
Consider worst case cable resistance + Cable impedance at any frequency to be 50nF and the worst case cable resistance to be 50ohms.
These are insanely high values that we will not encounter in any cable.
The -3db cutoff for these values turns out to be around 64KHz which is 3X the audio bandwidth.
So the pass band which is the signal (audio) content will remain unaffected.

If your cable parameters are worse than these, change the cable. Done!!

I have done this in a hurry. Kindly correct me if I have neglected anything.

Regards,

Ravindra.

 

[Kannan]

@Ravindra Desai
i am an agnostic so prefer a scientific approach or seek explanation in that regard.

I had this experience in AV Lounge (a hifi showroom in Chennai). A 4-way speaker model he had included an ultrasound generator that could play from 30 khz to 100 khz, way beyond the human audio range.

On its own, it was dead silent to the ears when fed audio signal, but when it was part of the 3-way chain there was a clear added width and airiness to the stage with the generator engaged and disengaged.

I still do not say the generator was audible to my ears, but was probably contributing to the tweeters high frequency band.

 

[Ravindra Desai]

@Ravindra Desai
i am an agnostic so prefer a scientific approach or seek explanation in that regard.

I had this experience in AV Lounge (a hifi showroom in Chennai). A 4-way speaker model he had included an ultrasound generator that could play from 30 khz to 100 khz, way beyond the human audio range.

On its own, it was dead silent to the ears when fed audio signal, but when it was part of the 3-way chain there was a clear added width and airiness to the stage with the generator engaged and disengaged.

I still do not say the generator was audible to my ears, but was probably contributing to the tweeters high frequency band.

Its called adding dither.
You and I should not be resorting to dither (high frequency signals) to create airiness! We are purist audiophiles (oh man!)!
b.t.w. all 'branded' amplifiers purposely have their b.w. limited to around 20K, no?
So 30K upwards affecting sound quality........eh......let's not get into that, ok?

Regards,

Ravindra.

 

[keith_correa]

Hello,

Here is my math model:

If you will all agree:
Cable has an effect of low pass filter. Its effect will be noticiable in high frequencies.
The cable resistance and the cable inductance forms the series arm of this low pass filter and the cable capacitance forms the parallel arm of the low pass filter.
Consider worst case cable resistance + Cable impedance at any frequency to be 50nF and the worst case cable resistance to be 50ohms.
These are insanely high values that we will not encounter in any cable.
The -3db cutoff for these values turns out to be around 64KHz which is 3X the audio bandwidth.
So the pass band which is the signal (audio) content will remain unaffected.

If your cable parameters are worse than these, change the cable. Done!!

I have done this in a hurry. Kindly correct me if I have neglected anything.

Regards,

Ravindra.

A cable will act in conjunction with source and driver values of impedance and capacitance. With that and the cable values you will be able to accurately model frequency and phase shifts. And don't consider 3db for anything. Let's go apeshit and consider +- 1db for the folks who have got bat ears.

 

[Kannan]

b.t.w. all 'branded' amplifiers purposely have their b.w. limited to around 20K, no?

This is a very valid point which makes a lot of sense.

So I looked at the specs of the amp that was driving the speakers
it was CAT SL1 tube mono blocks,
Its spec states (Frequency responses: 0.1Hz–800kHz, +0/–3dB (line input) and 20-20khz for phono.
At next visit let me try a comparison between phono input and line input.
Now I don't know what bandwidth restriction does the line input stage (DAC) offers.
The preamp by the way is also CAT with similar specs as per its roster.

Interesting and thanks for the clarification about the bandwidth restriction in amps

 

[Ravindra Desai]

A cable will act in conjunction with source and driver values of impedance and capacitance. With that and the cable values you will be able to accurately model frequency and phase shifts.

The above was a rough estimate on the amplfier input side.
On the amplifier output side, the loudspeaker impedance will dominate against cable impedance. So cable factors such as break and rust only will dominate. Speaker cable impedance or resistance will never be close to the speaker driver resistance or impedance.

And don't consider 3db for anything. Let's go apeshit and consider +- 1db for the folks who have got bat ears.

-3db was for bat ears.
You and I have accepted the now standard -10db specs!

This is a very valid point which makes a lot of sense.

So I looked at the specs of the amp that was driving the speakers
it was CAT SL1 tube mono blocks,
Its spec states (Frequency responses: 0.1Hz–800kHz, +0/–3dB (line input) and 20-20khz for phono.
At next visit let me try a comparison between phono input and line input.
Now I don't know what bandwidth restriction does the line input stage (DAC) offers.
The preamp by the way is also CAT with similar specs as per its roster.

Interesting and thanks for the clarification about the bandwidth restriction in amps

0.1Hz to 800KHz!!!??? Wow! Tube amp!! What about its slew rate? Is it a buffer power amp? Must have really realy low gain. Forget it. Must be a typo for sure.
Is it an Audio amplifier or RF amplifier or a dog whistle?
Anyway, I would not want the dogs in my neighborhood dancing and singing to such wide frequency b.w. amp, trust me, same applies for you.

Regards,

Ravindra.

 

[rikhav]

M

The above was a rough estimate on the amplfier input side.
On the amplifier output side, the loudspeaker impedance will dominate against cable impedance. So cable factors such as break and rust only will dominate. Speaker cable impedance or resistance will never be close to the speaker driver resistance or impedance.



-3db was for bat ears.
You and I have accepted the now standard -10db specs!



0.1Hz to 800KHz!!!??? Wow! Tube amp!! What about its slew rate? Forget it. Must be a typo for sure.
Is it an Audio amplifier or RF amplifier?
Anyway, I would not want the dogs in my neighbourhood dancing and singing to such wide frequency b.w. amp, trust me, same applies for you.

Regards,

Ravindra.

In the end if I hear a difference with my own ears I would not care what actual science teaches me or what others think and yes I believe in sound changing with cables
And that too with well made and we'll designed amplifiers and speakers

Nothing can be more true then what I get to hear with my own ears