8 kHz static noise in my audio recordings

  • Thread starter Thread starter fictionman
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I don't know but if different mics and cables don't eliminate the noise, it has to be something else. If you've used the same interface on 2 different computers and still had the noise, the interface and it's interconnects are the next place to look.

Yes, I understand.
But it won't be easy to test this, because I have only one audio interface...
Thanks for help
 
Yes, I understand.
But it won't be easy to test this, because I have only one audio interface...
Thanks for help

Take your laptop to a completely different location, not just another room in your house, to see if the noise follows you. If it does, it isn't interference from without but a failure in your interface.
 
There are two antennas about 1 kilometer (0,6 mile) from my flat.
Do you think it could be this?
I already have a wireless mouse but my keyboard is wired.
And, what do you mean by "I redid the system's speakers"?
Thanks for help.

I got rid of the computer speakers, added a pair of JBL 305s, and fashioned the cables using sheilded wire (basically cut a mic cable in half and changed the XLR connector on one end.)

BTW, looking at the frequency spectrum of your noise, there were some peaks around 1000, and then it looks like you have a pair of noise peaks at 8K and 16k which are very similar, like one is a second harmonic of the first. I'm not sure what it could be. 8k would have to be the fundamental, as there is nothing at 4kHz.
 

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Since it seem this could be RF getting in via the microphone try wrapping it* in extra thick chicken foil taking care that foil grounds via the XLR body. Also check with a meter that pin 1 of the XLR connects to the shell. This used to be contentious but now the practice is to bond shells to pin 1.

*Of course, this renders the mic useless but. 'Just testing'!

Dave.
 
Did you get to the root of this fictionman? I have EXACTLY the same irregular pattern of issue on dynamic mics/guitar pickups at the exact same frequency on two interfaces. Condenser is crystal clear. I have gone to extensive lengths to try isolate the source to no avail.

Plight
 
Fictionman was last seen here in 2021 so unlikely, although not impossible, that they'll respond.
I wasn't involved in this thread but reading it back I don't think Fictionman ever described their microphone or cable.

The responses make the assumption of balanced microphone, cable, and input.
I'd bet the input wasn't balanced. ^

Assuming your condenser mic is phantom + balanced, your experience would go some way to supporting that idea.

The advice, I guess, would remain the same - Change everything, bit by bit.
Different cable, different mic, different computer, different power source (battery if possible), different room, different house and, if necessary, different town. :ROFLMAO:

Edit: I've used electric guitars as scanners before, to pinpoint a source of interference.
Might be useful?
 
Fictionman was last seen here in 2021 so unlikely, although not impossible, that they'll respond.
I wasn't involved in this thread but reading it back I don't think Fictionman ever described their microphone or cable.

The responses make the assumption of balanced microphone, cable, and input.
I'd bet the input wasn't balanced. ^

Assuming your condenser mic is phantom + balanced, your experience would go some way to supporting that idea.

The advice, I guess, would remain the same - Change everything, bit by bit.
Different cable, different mic, different computer, different power source (battery if possible), different room, different house and, if necessary, different town. :ROFLMAO:

Edit: I've used electric guitars as scanners before, to pinpoint a source of interference.
Might be useful?
Thanks for getting back so quickly on an old thread! That’s a helpful observation on the specifics of OPs chain.

Okay, time I stop kicking the can down the road, head to the woods nearby and run everything on battery 😂 knock out the gear in isolation in a quiet environment, then build out from there!

The tip with the electric guitar will be helpful because it’s unpredictable. One strange thing I have noticed is that playing an acoustic guitar near a dynamic microphone (not through DI) appears to more readily trigger the response.

If I do crack this nut I’ll come back and post my findings for posterity!
 
Fictionman was last seen here in 2021 so unlikely, although not impossible, that they'll respond.
And on GearSpace with the same problem in January 2020 - He got similar advice - some more technical - and with the same results - he ducked out without reveling anything about his microphone or doing anything different than he mentioned here - if I was to guess he looks like a troll seeking attention.
 
One strange thing I have noticed is that playing an acoustic guitar near a dynamic microphone (not through DI) appears to more readily trigger the response.
Oh? That might blow my idea apart.
Is that a balanced mic and input, and XLR to XLR cable?
 
Oh? That might blow my idea apart.
Is that a balanced mic and input, and XLR to XLR cable?
It seems odd, doesn't it? I understand the full chain is balanced. I'm happy to spin up a new post if it's more appropriate before launching into fresh discussion. What struck me about OP's post is the very close similarities of our problem. The setup I have is:

Interface: Focusrite Scarlett 18i8 3rd Gen, Audient iD4.
Issue occurs with: Shure SM57, SM58, Fender Stratocaster.
But not with: Rode NT1 5th Generation on phantom power.
Cables (both tested): XLR to XLR Nuetrik NC-MXX connectors, Sommer SC Club Series MKII (cable 1, 3m), Rode Professional (cable 2, 5m).
Laptop: MacBook Pro M1 Max.

Audio sample from Focusrite attached (occurs when monitoring and recording), first two tones recorded simultaneously.

Tone 1: SM57
Tone 2: SM58
Tone 3: Stratocaster (humbuck pickup near bridge, balanced TRS)

So the SM57 and SM58 pick up the same signal, but when I had the Rode and SM58 plugged into two different XLR inputs, the SM58 would pick up the signal, but the Rode would not.

I moved into a new flat, purchased the dynamic mics (my first dynamics) and Focusrite all at the same time, so I had three new variables to deal with.

The furthest I have gone to date to isolate the cause(s) was to run the Audient iD4 with the MacBook and no other peripherals, no bluetooth, and no wifi, in another room, turning off the entire mains power in my flat (just long enough that the freezer wouldn't defrost :ROFLMAO:). The issue was prevalent to the same degree in that second room. And walking around the room, changing the position of the mics/guitar did not affect the strength of the signal. Pulling the cable from the interface killed the signal immediately, but I don't believe I tried pulling the cable out of the microphone/guitar. I took away from the testing that the problem certainly seems to originate from the similar and more sensitive components of the guitar/microphones picking up a strong external signal, and are frustratingly most easily triggered by producing sound, even by an acoustic guitar that's not plugged into anything.

My next steps:
1) Do a field test at a friend's house.
2) I've ordered a Gotham GAC-3 with Neutrik EMI XLR ends so I have a RFI-resilient cable to add to the chain. Doesn't hurt to have this regardless.

Frequency Spread.webp
 

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Long shot but do you have anything you could use to safely create a path between earth and your interface chassis?

I recall having a similar issue with a dell laptop years ago - Its power supply was isolated from mains earth and I had similar issues unless I manually crated a path.
In my case it was enough to have a TS cable connected between an unused interface output and a mixer, or monitor speaker, input.

Of course don't do anything you're unsure about or uncomfortable with but if you have a mains powered audio device, like a stereo amplifier, monitor speakers, mixer that you could hook up, safely, for testing, it might reveal something.

I guess this suggestion depends on where you live - I'm in UK where there is a third dedicated earth pin on all our plugs.
 
I bought two of these - and they are great for isolating line level signals, or mics - xlr or jack in and out - just transformers and ground isolation. aliexpress
 
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