Power cables for active speakers - do they matter?

[RexrothPigeon]

Anti-subjective squad has already descended here

as has the peanut gallery, I guess

 

[Avp1]

For me, I use active Neumanns, and paired them with reasonably priced Belden 19364 power cable (shielded being most important to me).

/

Supra Cables Lorad type are somewhat shielded too. They have kind of conductive fabric wrapping wires under outer PVC insulation. They said this is their know-how. I never saw that sort of arrangement before: https://supracables.se/shop/power/mains-cables-110-250v/lorad-3x2-5-blue-b50/

 

[MarkS]

My expectation was NOT to hear any difference

Completely irrelevant.

You either listened blind, or you did not.

And you did not.

End of story.

 

[mcdn]

We did not know which cables will be tested. Thus no prior expectation. Moreover selection of sequence was completely random and host who swapped cables did not hear them before in his system or elsewhere. Thus there was no preconception what we should hear with each cable change. So I would say that there was a real difference in sound. But there was no control, like cheap stock cable in the bunch. Thus no baseline set at all.

I've been there myself with interconnects. ABX is the standard for a reason, and when properly implemented the change will disappear.

Think of it this way - if you could in fact reliably distinguish two power cables in a 20 trial ABX test where the person making the changes also did not know what cable was being used, then you would genuinely advance the state of the audio art.

 

[JSmith]

So were coathangers in the mix?


JSmith

 

[theREALdotnet]

Power cords are definitely directional, that's all I can say.

 

[GXAlan]

UMIK-2 and measurements followed by recordings of the music that you find the most reliable to have a difference.

1) do a few measurements of the same cord to capture the variability of your technique. Ideally a quiet room with you out of the room is best.

2) then DeltaWave to compare recordings. Look for patterns.

3) Then take the best recording from one cable and the best recording from the other. Post it here to see if we can figure which is which. You said one sounds more transparent. See if anyone else figures it out.

4) Use Foobar to generate ABX testing. See if you can hear it yourself.

 

[JSmith]

JSmith

 

[kemmler3D]

Spacial details like reverb tails were better heard with new cables. This is not what I expected from ATC speakers, but that was real and confirmed by someone who has no stakes in that game.

Tell me: how to quantify that? This is a serious question.

If there is a real difference in clarity as you describe it will show up as:

Lower distortion (THD or IMD)
Lower noise floor
Higher output by ~1dB or so

You may be able to capture such differences with a mic at the speaker.

I'll also say that it's pretty trivial to get people to hear stuff that isn't really there if they are primed to expect a possible difference, especially a "small but noticeable" one.

It's very likely the differences you heard in both situations would go away if you took the trouble to do a full blinded ABX test.

 

[Avp1]

So were coathangers in the mix?


JSmith

They were! Original cables were no-name, or rather unknown name - some company in Italy made them. They make a lot of wire products for all kind of use. Looked like any 15A computer power cables with molded connectors. If I recall correctly they were supplied with ATC speakers when I bough them.

 

[Sir Sanders Zingmore]

It's very likely the differences you heard in both situations would go away if you took the trouble to do a full blinded ABX tes

100% agree.
@Avp1 will you do a properly blinded test?

 

[Avp1]

UMIK-2 and measurements followed by recordings of the music that you find the most reliable to have a difference.

1) do a few measurements of the same cord to capture the variability of your technique. Ideally a quiet room with you out of the room is best.

2) then DeltaWave to compare recordings. Look for patterns.

3) Then take the best recording from one cable and the best recording from the other. Post it here to see if we can figure which is which. You said one sounds more transparent. See if anyone else figures it out.

4) Use Foobar to generate ABX testing. See if you can hear it yourself.

UMIK-2 is not resolving enough. Will need a proper high quality studio class mike to possibly capture nuances of sound in my room. Whatever difference is present - it is very close to noise floor or under noise floor.

 

[Avp1]

If there is a real difference in clarity as you describe it will show up as:

Lower distortion (THD or IMD)
Lower noise floor
Higher output by ~1dB or so

You may be able to capture such differences with a mic at the speaker.

I'll also say that it's pretty trivial to get people to hear stuff that isn't really there if they are primed to expect a possible difference, especially a "small but noticeable" one.

It's very likely the differences you heard in both situations would go away if you took the trouble to do a full blinded ABX test.

Could be difference in noise floor or specific pattern in the noise. Could be distortion pattern (how harmonics relate to each other), But I expect it to be very small. There was one track out of mix, where neither me nor my wife heard any significant difference.

I suspect it all can be related to how amplifier reacts on RF interference. Shielded cable works as additional filter.

Interestingly I did measure capacitance and inductance of cables. New cable had higher (+70%) capacitance and my RLC meter could not measure inductance at all. I measured inductance of old cable without issues.

 

[respice finem]

I do not usually engage in such discussions any more, but I see another cause: plain old fraud and deception. I've once (last Millennium) caught a dealer of rather pricey turntables using Cinch resistors to make the cheaper one worse (quieter). Others may be far more creative...

Based on logic alone: Academically assuming, one power cable were somehow "better" - that would be 2 m or so, what about the totally "unaudiophile" kilometers to the power plant?

One take from a known "mythbuster":

 

[Avp1]

I see yet another possibility: plain old fraud and deception. I've once (last Millennium) caught a dealer of rather pricey turntables using Cinch resistors to make the cheaper one worse (quieter). Others may be far more creative...

Based on logic alone: Academically assuming, one power cable were somehow "better" - that would be 2 m or so, what about the totally "unaudiophile" kilometers to the power plant?

This is why I made cable myself. Wire and connectors are normal from power transfer point of view. Good 2.5mm2 wires for line, neutral and ground. UL certification lab won't approve anything out of normal in that regard.

In our club testing some cables were worse than one which host used daily, despite their higher price.

 

[respice finem]

I didn't say the cable is manipulated. It may be anything in the chain.

 

[kemmler3D]

I suspect it all can be related to how amplifier reacts on RF interference. Shielded cable works as additional filter.

Let's zoom out a little here, though. If your speakers' amps are this sensitive to RF interference, wouldn't you be hearing differences in sound quality all the time due to interference coming through the air? The power cable is not the only source of RF that might reach the PSU or amp.

I just want to share that heard differences that aren't coming from the gear are just as convincing as heard differences that do come from the gear. You really do hear them... which then leads to a quest for an explanation in the gear, rather than the mind. It is only easy to dismiss these kinds of things when it's immediately obvious you've been listening to nothing. I've heard real changes in sound from tweaking DSP plugins that were mistakenly turned off. It happens to a lot of studio folk over time.

I only point this out because I've never seen a test of a power cable show any plausible change in audio output. Amp designers know that power quality is garbage in most homes and account for this in the design. I am not saying it's impossible for audio cables to change the sound (not literally), but I do know it's almost impossible to NOT hear a difference in a test like the ones you've described, regardless of how the gear is behaving.

 

[Avp1]

Let's zoom out a little here, though. If your speakers' amps are this sensitive to RF interference, wouldn't you be hearing differences in sound quality all the time due to interference coming through the air? The power cable is not the only source of RF that might reach the PSU or amp.

I just want to share that heard differences that aren't coming from the gear are just as convincing as heard differences that do come from the gear. You really do hear them... which then leads to a quest for an explanation in the gear, rather than the mind. It is only easy to dismiss these kinds of things when it's immediately obvious you've been listening to nothing. I've heard real changes in sound from tweaking DSP plugins that were mistakenly turned off. It happens to a lot of studio folk over time.

I only point this out because I've never seen a test of an audio cable show any plausible change in audio output. Amp designers know that power quality is garbage in most homes and account for this in the design. I am not saying it's impossible for audio cables to change the sound (not literally), but I do know it's almost impossible to NOT hear a difference in a test like the ones you've described, regardless of how the gear is behaving.

Whatever the difference is - it is very subtle. Need very high quality source record to hear it. It could be that amplifier does not behave in the presence of interference. This is only a limited filtering you can fit into active speaker amplifier pack. There is a lot of RF noise around, and all cables behave as antennas. If it is indeed RFI, this is practically unmeasurable or any attempt to measure changes condition too much. This is why protection from RFI is more art than science.

I now plan to change power cables for preamplifier and DAC, add linear power supply for streamer and use fibre instead of CAT6 to bring network to streamer. I honestly do not know if there will be any advantage from all that. But I try to exclude all possible interference sources.

 

[Devnull]

UMIK-2 is not resolving enough. Will need a proper high quality studio class mike to possibly capture nuances of sound in my room. Whatever difference is present - it is very close to noise floor or under noise floor.

And if it's really that close to the noise floor or under it you can't be sure what you're measuring because of variable environmental conditions. You'd be better off using an oscilloscope and measuring a static temperature controlled load, powering everything off a sine wave UPS to take incoming power variations out of the equation in a shielded anechoic chamber. Or you could just use a well made power cable and enjoy an adult beverage with the wife while you listen to some music. I know which one I'd choose.

 

[kemmler3D]

Whatever the difference is - it is very subtle. Need very high quality source record to hear it. It could be that amplifier does not behave in the presence of interference. This is only a limited filtering you can fit into active speaker amplifier pack. There is a lot of RF noise around, and all cables behave as antennas. If it is indeed RFI, this is practically unmeasurable or any attempt to measure changes condition too much. This is why protection from RFI is more art than science.

Take the door off a microwave, defeat the safety latch, and point it at your amp from across the room... if it's sensitive to RF you'll notice very quickly