RF Interference in Speaker Cables??? (video)

[MakeMineVinyl]

I might relate a phenomenon I've experienced for years where I hear a buzz coming from my HF horns even when the sound system is completely powered down. Note that the speaker I'm talking about is a horn which operates from 500Hz up, and has 107dB efficiency. This buzz is undoubtedly coming from a dimmer I have in the room because as I dim the lights, the quality of the buzz changes. So there is some EMI coupling somewhere between the amplifier (tube) and the speaker, probably the speaker cables which are about 10' long.

This buzz persists when the system is powered on. Does it matter? No. Is it intrusive? No, unless I have my ear literally crammed into the mouth of the horn. Would I hear this buzz if my speakers were more 'normal' efficiency? Undoubtedly not.

So speaker cables can, at least with highly efficient speakers, pick up EMI/RFI which can be heard. Again, it only matters in highly atypical situations such as mine.

 

[tomchr]

@amirm Have you ever thought of trying to quantify if any aspects of speaker cable design DO make a difference? AWG? Capacitance? Inductance? Length? Twisted conductors vs parallel? Maybe measure the same speaker/amp combo multiple different ways with only the speaker cable changing?

Cross-sectional area is the main driver, but you only have to get above AWG 16 for it to no longer matter.

Oldie but goodie:
https://www.soundandvision.com/content/speaker-cables-can-you-hear-difference

Tom

 

[phoenixsong]

Hard to tell what went wrong, maybe the adapter, maybe the studio ghost, maybe something faulty, may be a weird TRS config, maybe poor Shielding on the Senn cable, maybe different gain structure between the two use cases tested.

Definitely not the adapter- there is no buzzing/humming unless the phone is brought close to the cable. Can't be anything faulty, it works like a charm apart from this occasional issue with this particular cable. I don't think it is a weird TRS config as TRS is supposed to be standard and it isn't likely for Sennheiser to breach adherence to this

 

[VintageFlanker]

I guess you noticed this, @amirm ...

Yes, please "both find the time"!!

 

[Lambda]

Pleases also bring the following people to the thunder dome!

EthanWiner
https://www.youtube.com/user/EthanWiner

Julian Krause
https://www.youtube.com/user/JayKayRause

Doug Ford

Sound speed
https://www.youtube.com/channel/UCjL6MFoRxI9dbybAYO4uNzA

Sam Inglis S.O.S.
https://www.youtube.com/channel/UCFw2zGrdiLLAwbNQra1vtnA

 

[PeteL]

Definitely not the adapter- there is no buzzing/humming unless the phone is brought close to the cable. Can't be anything faulty, it works like a charm apart from this occasional issue with this particular cable. I don't think it is a weird TRS config as TRS is supposed to be standard and it isn't likely for Sennheiser to breach adherence to this

I am not sure what you are trying to say? That a xlr to TRS connection is unbalanced? If it is, something went wrong in the chain, that's all, I am sorry I don't have an answer to why it happened. Plus most of the time those cables are used to connect to sennheiser Belt packs, so proprietary wiring is not something we can dismiss unless we see a wiring diagram, which are not supplied with the link you sent me.

Edit: after digging a bit more, I guess we where both right, the wiring of the cable you showed me is "unbalanced", but it is not proper TRS wiring it's custom pinout for the Sennheiser transmitters.

 

[amirm]

Yes, please "both find the time"!!

I am happy to do a video with Gene. In general though, as you have seen, I like the videos to be informative and have real data in them. Us getting together and complaining about the other camp is not what I like to do with the video format.

 

[mansr]

I am happy to do a video with Gene.

Maybe you can help him fix the dreadful sound quality in his videos.

 

[Lambda]

Im sure you need a moderator!
The number one youtube engineer that comes to my mind is Dave Jones... maybe ask him if he can help debunk.

also interesting and related paper from TI:
https://www.ti.com/lit/an/sboa128a/sboa128a.pdf?ts=1613758653068&ref_url=https%3A%2F%2Fwww.google.com%2F

 

[JimWeir]

I don't know how I got dragged into this but thought I do a video showing the proper effects of RF on speaker cables and what it takes to demonstrate audibility. I thought it needed to be done even though I did not want to engage in any tit for tat type of videos.

One cannot overstate the effect of the minds processing to produce “the sound” of our systems. All we get are two somewhat correlated pressure variations at our ears. Those pressure variations are a convolution of the room and loudspeaker and (minimally) electronicsimpulse response on the two signals that are “the art” produced in the mastering process. AND, the producer or artist, when creating that art are listening to two (different) somewhat correlated pressure variations that were consoled from the same signals through different acoustics and gear.
The fact that our brains (and the producer’s brains) imagine a multidimensional event from those two dimensionless signals is the true miracle of the hobby and art form we call stereo reproduction.

The cable and tweak makers and reviewers and most the high end audio market thrive on this transition that happens between the signals and “the sound”. Heyser wrote about this transition on his articles in Audio Magazine “The Catastrophe Theory”.
We each have a perceptual “Manifold” that varies and draws on current stimulus and past experiences. The manifold takes the pressure variations and tries to remap them into some form of believable illusion. The quality of the illusion is dependent on the confidence we have in the whole process chain - from the original recording, all the transmission and processing that happens along the way.
Burn in, Listening Fatigue, and cable risers, power cords, and all the “Magic” that does not follow science are reliant on “real” changes that happen the our perceptual decoding manifold.
Modern science has looked at the difference in the parts of the brain that are active in individuals that experience live vs reproduced music reproduction. In live music much less of the brain gets involved.

check out this link. https://www.medicalnewstoday.com/articles/266426

 

[solderdude]

I might relate a phenomenon I've experienced for years where I hear a buzz coming from my HF horns even when the sound system is completely powered down. Note that the speaker I'm talking about is a horn which operates from 500Hz up, and has 107dB efficiency. This buzz is undoubtedly coming from a dimmer I have in the room because as I dim the lights, the quality of the buzz changes. So there is some EMI coupling somewhere between the amplifier (tube) and the speaker, probably the speaker cables which are about 10' long.

This buzz persists when the system is powered on. Does it matter? No. Is it intrusive? No, unless I have my ear literally crammed into the mouth of the horn. Would I hear this buzz if my speakers were more 'normal' efficiency? Undoubtedly not.

So speaker cables can, at least with highly efficient speakers, pick up EMI/RFI which can be heard. Again, it only matters in highly atypical situations such as mine.

Have you tried, just for fun, disconnected it from the amp and then listened ?
Do you have such a length of twisted cable or coax and tried that.
Just to satisfy one's curiosity ?

 

[tomelex]

Consequent shielding / filtering on the input/PSU/preamp side perhaps? At a neighboring neurology ward (last millenium) there was a patient who could (evidently) occasionally hear LW AM radio (one station only) because of an old shrapnel in his head. So yes, weird stuff happens (very weird in this case).

When I was a kid, about 10 years old, my old bed had a ton of big springs in it. Sometimes, at night, when I lay just right, I could hear morse code. The bed springs, and the other metals in the bed, were demodulating the morse code signals from some nearby ham radio transmitter, and there was enough energy making the actual springs move, hence creating sound. My dad "believed" me but wanted proof, so finally one night I called out to him and he came in and I told him dot , dot dash, dash etc and he then confirmed it was real, as he was a radio operator at one time in WW2. Funny how that got us both interested in amateur radio from that point on and jump started my electronics career. Only many years later was I able to explain to Dad what was actually happening using science.

 

[MakeMineVinyl]

Have you tried, just for fun, disconnected it from the amp and then listened ?
Do you have such a length of twisted cable or coax and tried that.
Just to satisfy one's curiosity ?

I'm not curious enough about this since I never use that dimmer when I'm listening; I have relay controlled lights for that which are either on or off and there is no buzz then. The buzz is just something I notice when I enter the room to fetch something and turn that dimmer controlled light on. Those horns are insanely sensitive, especially since they are run off an active crossover before the power amp, so the horns are directly connected to the amp. I've run them for fun off of a small transistor radio (with a capacitor high pass) and they went extremely loud.

 

[amirm]

The number one youtube engineer that comes to my mind is Dave Jones... maybe ask him if he can help debunk.

I don't need his help but he has done one such video:

 

[Bruce Morgen]

Is there such thing as an unbalanced mic cable? Define cheap?

Virtually every PeeCee headset with a TRRS plug has an unbalanced mic circuit -- and back in the day even legit pro audio mic suppliers like Shure and E-V sold high-impedance versions of many of their classic models -- with unbalanced shielded cables included for connecting to guitar amps and old-style P.A. systems.

 

[Lambda]

he has done one such video

I think this disquiets him as unbiased.
but how can a engineer be unbiasd on an topic like this

 

[PeteL]

Virtually every PeeCee headset with a TRRS plug has an unbalanced mic circuit -- and back in the day even legit pro audio mic suppliers like Shure and E-V sold high-impedance versions of many of their classic models -- with unbalanced shielded cables included for connecting to guitar amps and old-style P.A. systems.

I get that, but what we are normally reffering to a microphone cable, especially if the poster suggest swapping one for the other, suggest a 3 conductor + shield connection. I wanted to point out that XLR is not what makes it balanced, that if it's TRS terminated, it's not for this reason alone that the system would become unbalanced, that's why I wanted more information.

 

[richard12511]

"100MHz... we can't hear 100 KHz, how are we gonna hear 100MHz"

That actually made me laugh out loud when I heard it. Not just 100MHz, but 100MHz at 2 microwatts fully amplified.

 

[GGroch]

One cannot overstate the effect of the minds processing to produce “the sound” of our systems....... We each have a perceptual “Manifold” that varies and draws on current stimulus and past experiences.......Modern science has looked at the difference in the parts of the brain that are active in individuals that experience live vs reproduced music reproduction. In live music much less of the brain gets involved......

Very Interesting stuff! Your argument reinforces the findings described in tomchr's excellent post about conformity bias tests by Asch and later Greg Burns. In 2005 Burn's measured brainwave activity to prove that conformity bias alters the perception of test subjects at the neurological level, that is, "social conformity literally causes their brains to rewrite reality."

I previously thought of bias as nearly imperceptible prejudice that nudges us towards conclusions that are not objective. Your references and Asch/Burns suggest it can be far far stronger than that, totally upending our ability to perceive reality.

 

[richard12511]

I don't need his help but he has done one such video:

Hahaha that was a great video!