EMI/RFI on cables, some objectively quantifiable data

[Ghoostknight]

Hello, i found this video in the depths of youtube and i found the test (and testsetup) pretty unique and interesting



while the nay-sayers will definitely argue wether -90db vs -112db is audible "at all" this test actually shows a real world situation instead of glorified theories and how different cables can matter

regarding EMI/RFI filtering i also found this video on his channel:


first time actually hearing about the EMC connector( Neutrik XLR connector similar to your usual ones but it includes an EMI filtering board and better shielding), i might give this a shot in the future

 

[dunring]

I stick with optical USB cables now that prices have come down thanks to VE headsets using them. Star quad Amazon Basics XLR is all I need. Gearit cables also measures well on my basic test equipment. Amir on audio science review did professional measurements on a few sets a while ago, World's Best, Amazon, and a cheap generic cable.

 

[Ghoostknight]

I stick with optical USB cables now that prices have come down thanks to VE headsets using them. Star quad Amazon Basics XLR is all I need. Gearit cables also measures well on my basic test equipment. Amir on audio science review did professional measurements on a few sets a while ago, World's Best, Amazon, and a cheap generic cable.

i know some of these tests, tho i wonder whether the right stuff gets actually measured as the youtube video is a good example of how it can go wrong tho the culprit of the results in the first video could be the ADC itself

even if a ADC/DAC can "properly" filter the noise in the audioband, it can only do so much till outside noise creeps into the output is atleast my guess, maybe the video demonstrates a particular bad case of EMI and less effective filtering inside the ADC but its a "real difference" where cables apparently matter

 

[gregorio]

while the nay-sayers will definitely argue wether -90db vs -112db is audible "at all" this test actually shows a real world situation instead of glorified theories and how different cables can matter

even if a ADC/DAC can "properly" filter the noise in the audioband, it can only do so much till outside noise creeps into the output is atleast my guess, maybe the video demonstrates a particular bad case of EMI and less effective filtering inside the ADC but its a "real difference" where cables apparently matter

Oh god, here we go again!

You take something that you don’t understand, come up with a “my guess” which doesn’t even pertain to what you’re claiming because you don’t understand what is being tested (or why) and then formulate a conclusion that can only be nonsense because it’s based on NOTHING other than your misunderstanding and guessing. Why do you do this and in a science discussion forum of all places? Do you even know what the guy presenting the video does, what his job entails or who the videos are aimed at?

The test does “actually show a real world situation”, it’s just a completely different real world situation to that encountered by consumers when reproducing audio recordings. Working 100m below the sea is also “a real world situation”, does that mean audiophiles in their sitting room should wear an aqualung and decompress for 10 hours after listening to a Taylor Swift song?

Come on, use your brain to do something other than just invent nonsense, even if that just means asking if you don’t understand what is being tested or it’s context, even a child can do that!

G

 

[frkasper]

The real world situation from the guy in the video is likely not a real world for a typical audiophile. Note that I always analyze the noise floor on my gear using the most sensitive transducers I have on hand. And I have fun doing that kind of exercise. But it always boil down to noise levels being so low that I simply don't care about EMI/RFI on my desktop setup. Which is always a good finding nonetheless.

Now, to the elephant in the room. That does not mean I haven't had EMI episodes in the past. I did, and with a simple dongle connected to my cell phone while listening to an IEM at a lower volume. And that EMI was in the audible range. But the challenge is that this noise come and go, so it makes really hard to reproduce it consistently. I had maybe 1-2 episodes in the past 4 years. But nothing to worry about either.

If one wants to reproduce EMI, it is actually easy to do it in single ended headphone amps. All one needs is a very quiet audio file — with like 90dB attenuation — and crank the volume in the amp (in high gain) while playing this file — be careful with OS notifications. One may be able to hear a faint "coil whine" type of noise depending on the amp and/or the transducer used. And that is very likely to be EMI.

I do like this (noise) theme, but people tend to romanticize it a lot. So, to your sentence...

while the nay-sayers will definitely argue wether -90db vs -112db is audible "at all" this test actually shows a real world situation instead of glorified theories and how different cables can matter

Should one really care about those noise levels? Well, I don't.

Cheers.

 

[XTF1]

does that mean audiophiles in their sitting room should wear an aqualung and decompress for 10 hours after listening to a Taylor Swift song?

I think they should !!!

 

[gregorio]

The real world situation from the guy in the video is likely not a real world for a typical audiophile.

Just for reference and clarity, the guy in the video is a member of a “production sound” team, specifically a “boom operator” and this is the target audience for his YouTube channel. A production sound team is a small group of people responsible for recording the dialogue during the shooting of TV and film content on set/location. The circumstances of a production sound team really could not be more different to a typical audiophile. Firstly, the guy is testing mic cables. Secondly, he’s recording into a field recorder. Thirdly, a considerable amount of post production will be performed on the material that is recorded and Lastly, the environment where the production sound team are recording could hardly be worse. The actors/presenters they are recording will each be wearing a quite powerful radio transmitter, each operating at a slightly different frequency (to transmit the signal from the lavalier mics) and of course the boom mic will be pointing directly at the actor wearing the transmitter. In addition, there will typically be time-code being broadcast wirelessly on set, very possibly walkie-talkies and a monitor mix from the production sound mixer (for the director/1st AD, etc.) being broadcast and Lastly, there will be a whole bunch of batteries being charged, banks of lighting units, probably a generator on location, transformers and AC/DC converters and power cables everywhere, all of which are high sources of EMI/RFI and that’s before we consider the EMI/RFI of the environment where they’re shooting.

In addition, contrary to ghoostknight’s assumption, a field recorder is not a DAC or even just an ADC/DAC but a fairly complex bit of kit with 8 or more channels, mix capabilities, built-in limiters and mic pre-amps and various other features. The exact settings were not revealed by the guy presenting the video but he did reference an almost identical test he’d done previously with cables where the mic-pre was set at 59dB gain, thereby obviously increasing the effects of any EMI/RFI by 59dB and he deliberately tried to induce as much as he could to start with, the cables were wrapped around a bunch of “wall warts”, two AC/DC converters, hung over his video monitor and next to his speakers.

Very little of the above is relevant or applicable to the situation of audiophiles.

G

 

[bigshot]

I was a boom man early in my career. It’s a very difficult job. Getting the microphone into exactly the right place at exactly the right angle isn’t easy, and the whole environment of the set is averse to capturing good sound. I didn’t want to make it my career after doing it a while.