Power cables for active speakers - do they matter?

[MaxwellsEq]

Ask yourself (as an EE) what is it about power cables that could theoretically make such a massive change to an audio signal's frequency, amplitude or distortion that you could actually hear it.

Soundest piece of advice so far.

@Avp1 you should try the advice from @JeremyFife What is the mechanism causing the change given the hundreds of feet to your utility's transformer?

 

[solderdude]

@Avp1 already mentioned this. He measured 70% higher capacitance.
The claim is this works like an 'extra filter'.

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]

Just for fun: I once had to go to a psychiatrist (who knew I'm a doc myself) to be able to get a CCP I needed at that wild time (Poland around year 2000).
He asked me a bunch of questions, and got to the question "do your hear voices". Me: every day TBH.... But they all come from this (pointing at the phone)
He certified me as crazy enough then to have the permit.

 

[dasherzx]

different plug types can make a difference like a 2-prong and 3-prong due to grounding and stuff but otherwise absolutely not. or are we talking about the audio cables if thats the case yeah i did buy an extremely poorly made 8m long rca cable from the flea market that totally lacked hf and could only hear bass out of it. but both of these are absolute outliers. they either work, or they're totally borked.

anyways, a simple youtube video of both cables playing the same content will let us all know if thats true

 

[kyuu]

OP seems to have made his mind up based on an invalid listening test, but just in case there's still some room for reason: your EE experience has not given you the understanding of how to perform a listening test that can determine if you are actually hearing a difference. Your controls are inadequate. People hear things all the time that have nothing to do with a change in the signal. You haven't even ensured that your levels are matched, let alone making sure that there is nothing else that can influence your perception besides the actual sound.

It doesn't matter what your expectations are. It doesn't matter how many wives you pull in. You are chasing ghosts until you perform a proper listening test to make sure you are actually hearing something. This has been demonstrated over and over and over and is why double-blind testing is mandatory for actual scientific conclusions. You can't reason or bias your way out of your possession of a normal human perception system that involves your brain and multiple other senses.

Or keep chasing your tail. It's your time and money.

 

[Avp1]

anyways, a simple youtube video of both cables playing the same content will let us all know if thats true

I do not think the difference has enough magnitude to survive mp4 compression used by YouTube.

 

[TrevC]

I do not think the difference has enough magnitude to survive mp4 compression used by YouTube.

Especially as you are imagining it.

 

[kemmler3D]

I do want to concur that it's almost always easier to measure something than to hear it. -60dB is easy to capture and see in many different visualizations, but not as easy to hear as we'd like to think.

 

[Bwaslo]

Curious what the signal input situation to the active speaker was (balanced or single ended)? Noise current between ac powered devices, running along the "ground" or "shield" return of an unbalanced signal input cable can be a very real thing. It shows up as a noise voltage on the input. We've all seen examples, obvious hum or buzz that changes depending on the outlets things are plugged into, or the particular power cables being used (none being actually "better" than others, just different and steering currents differently to flow along shields of signal cable). If balanced cabling is used, though, this shouldn't be an issue.

 

[rynberg]

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.

Nonsense like this is truly entertaining...please describe exactly what aspect of the UMIK-2 is inadequate compared to human hearing? You claim to be an engineer, so let's get into the weeds.

 

[Avp1]

Curious what the signal input situation to the active speaker was (balanced or single ended)? Noise current between ac powered devices, running along the "ground" or "shield" return of an unbalanced signal input cable can be a very real thing. It shows up as a noise voltage on the input. We've all seen examples, obvious hum or buzz that changes depending on the outlets things are plugged into, or the particular power cables being used (none being actually "better" than others, just different and steering currents differently to flow along shields of signal cable). If balanced cabling is used, though, this shouldn't be an issue.

Balanced all the way: DAC to preamp and preamp to speaker. Good quality Mogami starquad type cables. Actually signal cables made measurable difference - less high frequency noise spurs though all under -130dB.

 

[Avp1]

Nonsense like this is truly entertaining...please describe exactly what aspect of the UMIK-2 is inadequate compared to human hearing? You claim to be an engineer, so let's get into the weeds.

Dynamic range. Distortions not compensated by brain signal processing like in your head.

 

[mhardy6647]

sorry to be blunt, but sighted testing is nonsense, full stop:

I'll be a trifle more diplomatic. The problem with 'sighted' testing is that the experimenter is not testing what he/she/they think(s) he/she/they is/are testing.

 

[mhardy6647]

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

with occasional exceptions...

 

[egellings]

Once ampacity requirements (current carrying ability) are met, and ideally if a cord in question has UL or CE type safety approvals, then there cannot be any difference in sound quality caused by power cords. Of course, if a cord is too flimsy to carry the needed current, then S.Q. could suffer due to voltage sag. That would be the least of the problems, since cords, even thin ones, have a relatively low DCR, and it wouldn't take much of a voltage drop to overheat them into getting burning hot. So basically, the whole power cord controversy is a big nothingburger. Once ampacity requirements are adequately met, then they can have no effect on S.Q. whatsoever. HOWEVER, if a listener truly believes in their heart-of-hearts that adequately competent cord A sounds better than adequately competent cord B, then to them and them alone it will. I could see preferring one cord over another based on cost or appearance.

 

[Avp1]

Once ampacity requirements (current carrying ability) are met, and ideally if a cord in question has UL or CE type safety approvals, then there cannot be any difference in sound quality caused by power cords. Of course, if a cord is too flimsy to carry the needed current, then S.Q. could suffer due to voltage sag. That would be the least of the problems, since cords, even thin ones, have a relatively low DCR, and it wouldn't take much of a voltage drop to overheat them into getting burning hot. So basically, the whole power cord controversy is a big nothingburger. Once ampacity requirements are adequately met, then they can have no effect on S.Q. whatsoever. HOWEVER, if a listener truly believes in their heart-of-hearts that adequately competent cord A sounds better than adequately competent cord B, then to them and them alone it will. I could see preferring one cord over another based on cost or appearance.

I had the same stance, but when I found difference in test setup under my complete control, I was really surprised to find difference. I did not expect any.

 

[kharan]

The fact that 4 out of 5 people explained what they heard exactly with the same words surprised me even more. This was not a dealer presentation, so there was no push to choose a specific cable.

That is not very surprising, there's something that's referred to as group conformity where answers will tend to converge in a group. It is fairly flagrant in wine tasting for example where someone can start saying a wrong thing and people will follow regardless, and also start tasting an inexistent flavour note. This is such a huge problem that in any serious blind experiment, answers must be written down and set in stone before participants can start interacting with each other.

 

[mhardy6647]

There were the infamous curtain burner radios in another, simpler time.

Restoring the Curtain Burner Radio of the Early 1930s

Curtain burner resistance line cords create a whole new challenge when it comes to antique radio restoration.

www.nutsvolts.com

 

[egellings]

I had the same stance, but when I found difference in test setup under my complete control, I was really surprised to find difference. I did not expect any.

I would need to see that test setup & protocol. If testing is done on the power cord with a 50/60Hz test frequency using sensitive test equipment, then it might be possible to detect a tiny difference using that equipment to examine the cords. If a higher test frequency were used, then larger differences could show up. As for the listener hearing a difference between two adequate ampacity (current carrying capability) cords, I'd need to see the results of a blinded (preferably double blinded) test at matched volume levels using the same equipment to believe it. Sighted testing is simply not reliable. Of course, if you, in your heart of hearts, truly believe that cord A sounds better than cord B, then get that cord A and enjoy the music. Cord A will enable your belief filter, allowing you to enjoy the sound. If two adequate cords did actually cause a piece of equipment to behave differently, I'd be highly suspicious of the stability of that piece and would likely avoid acquiring it.

 

[sigbergaudio]

I had the same stance, but when I found difference in test setup under my complete control, I was really surprised to find difference. I did not expect any.

We all believe you heard a difference, we've all been there. My own favorite story is when we were two experienced speaker designers who heard the same effect after some digital crossover changes. The only problem was that we did the changes on a different preset than the one we were listening to. So the sound was exactly the same all along.

Have a look here: https://en.wikipedia.org/wiki/Cognitive_bias