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fictionman
Member
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
R
RRuskin
Rick Ruskin
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.
TalismanRich
Well-known member
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.
Attachments
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ecc83
Well-known member
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.
*Of course, this renders the mic useless but. 'Just testing'!
Dave.
plight
New member
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
Plight
Steenamaroo
...
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.
Edit: I've used electric guitars as scanners before, to pinpoint a source of interference.
Might be useful?
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.
Edit: I've used electric guitars as scanners before, to pinpoint a source of interference.
Might be useful?
plight
New member
Thanks for getting back so quickly on an old thread! That’s a helpful observation on the specifics of OPs chain.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.
Edit: I've used electric guitars as scanners before, to pinpoint a source of interference.
Might be useful?
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!
Papanate
Well-known member
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.
Steenamaroo
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Oh? That might blow my idea apart.
Is that a balanced mic and input, and XLR to XLR cable?
plight
New member
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
). 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.
Steenamaroo
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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 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.
rob aylestone
Moderator
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
plight
New member
Thanks for the helpful suggestions both.
I've extensively tested this outside of home and I can't replicate the interference. I'll do some further testing at home today, but all evidence suggests I'm battling something external that's intermittently causing this, maybe the lifts...
Steenamaroo - we do also have an earth pin in Australia. I'll have a play with creating a bridge between some different devices. There are grounding plugs I could explore, too, though wiring cables from a power mains makes me more than a little nervous I wonder if running on battery eliminates a potential grounding issue? Side note, your cover of Graceland is brilliant, do you write your own songs too?
Rob - thanks for sharing this, I'll trial one of these.
If this hardware filtering or the new cables don't help, I'll deal with it in post!
I've extensively tested this outside of home and I can't replicate the interference. I'll do some further testing at home today, but all evidence suggests I'm battling something external that's intermittently causing this, maybe the lifts...
Steenamaroo - we do also have an earth pin in Australia. I'll have a play with creating a bridge between some different devices. There are grounding plugs I could explore, too, though wiring cables from a power mains makes me more than a little nervous
I wonder if running on battery eliminates a potential grounding issue? Side note, your cover of Graceland is brilliant, do you write your own songs too?Rob - thanks for sharing this, I'll trial one of these.
If this hardware filtering or the new cables don't help, I'll deal with it in post!
Steenamaroo
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That would depend on the specifics of the problem.
With my issue I could read a very small voltage on interface/microphone/laptop "earth", with reference to mains earth,
so running on battery in that case would make no difference. The problem was a lack of proper mains earth connection.
Often when running on battery solves a problem the problem was two separate paths to earth with different potentials (ground loop),
and removing the power supply from the equation removed one path.
The fact that you've tested in your home with mains power off and had the issue should mean it's not interference from any of your own devices (boilers, AC, lighting etc),
but the fact that you've tested outside the home without the issue means your recording equipment isn't generating the noise.
Now, that doesn't mean some part of your recording equipment isn't damaged and susceptible to interference, but at least it tells us iit's not the source of it.
Is it possible the issue is present with the NT1 but it's just much less obvious, due the NT1 output being so much higher?
Might be worth plugging in, turning gain up to max, wrapping the mic in a blanket or two and recording as close to silence as you can for 30 seconds or so.
If you do that, share it with us, please.
I completely agree/understand. Don't do anything that makes you nervous,
but if you have a mixer, or monitor speakers, a guitar amplifier - Anything where the chassis is proper mains earth,
just connect that to your interface - line to line or whatever - and that will ensure a proper mains earth for your setup.
Do you have a multimeter?
It might be worth proving 0ohm between microphone grill and interface, and interface and laptop chassis.
There should be 0ohm between all of those but sometimes USB cables let us down.
Papanate
Well-known member
I’d put a couple of Ebtech’s Hum Xs on the wall - and plug all your stuff into those (with two powerstrips) - I suspect dirty power is the culprit - maybe your house is not grounded correctly - you could also look in the outlets with a Multimeter - don’t do this if you don’t understand the ins and outs of testing - but if you do there is probably voltage on ground leaking across - The Microphones are a red herring in terms of some buzzing - BTW What Guitar Amp do you have? Or do you have a Modeler or use Plugins - also if you can try grounding your Mac - the PowerSupply and a Ground Cable like the ones in the pictures.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
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.
View attachment 150178
Last edited:
Steenamaroo
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plight says the issue is present with the household mains supply shut off.
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ecc83
Well-known member
"Ooooo! Nasty!" (only Brits of a certain antiquity will get that reference!)
From all that that has been said before I have to conclude that this is a strong, external RF field.
Well, I SAY "RF" but either it is actually an 8kHz audio signal or it is a much higher frequency RF carrier that the interface is demodulating but what on earth could generate such powerful audio radiation I do not know*
Has another interface been tried?
*In my early teens I built a multivibrator using two KT66s. Ran at about 2kHz but squarish waves so the harmonics wiped out AM radio (all there was then) up and down the whole street.
Ferrite lumps everywhere and 1:1 transformers on the affected microphones is all I can suggest. That and find the source!
Dave.
From all that that has been said before I have to conclude that this is a strong, external RF field.
Well, I SAY "RF" but either it is actually an 8kHz audio signal or it is a much higher frequency RF carrier that the interface is demodulating but what on earth could generate such powerful audio radiation I do not know*
Has another interface been tried?
*In my early teens I built a multivibrator using two KT66s. Ran at about 2kHz but squarish waves so the harmonics wiped out AM radio (all there was then) up and down the whole street.
Ferrite lumps everywhere and 1:1 transformers on the affected microphones is all I can suggest. That and find the source!
Dave.
rob aylestone
Moderator
Nowadays, RF interference from HF, as in Short Wave stations is getting less as they all seem to be closing down. The thing with these RF sources is the power is related to audio, as they are AM in the main, so interference has a music 'rhythm' to it. Constant interference tends to be from FM or worse, digital transmission. Nasty stuff and far easier for it to get in. Worse, many digital systems transmit 24/7, if they are being used or not. These RF currents get picked up by the ground paths, so an aircon unit on a roof, floating on rubber mounts might well act like an antenna, allowing the RF in. Very often, an audio transformer can break that DC path, but letting audio through unmolested. Sometimes, the incoming RF mixes with signals generated in just one piece of kit. Two very high frequencies, way outside the audio band mix, and produce a sum/difference product. This could easily be within the audio bandwidth of just one of your devices, that are susceptible to stuff coming down the grounds. It's so easy to let these into the system. We have all, I'm sure, pulled out a jack plug from a guitar and discovered the cable acts like a mic when you tap it, or a zillion watts of nasty 50/60Hz hum burst out. All you have done is remove the cork from the bottle (as in the guitar from the cable, and all those noises that are there, suddenly have a way in. If you want to experiment - find the biggest old speaker you maybe have laying around. Old guitar or PA ones are ideal. Remove the circular magnet. Take the cable feeding the device you believe is letting the interference in. Wrap it as many times as you can through the hole in the middle - then tape it. You've made a really powerful (but mega magnetic, so take care) filter that allows audio through but works as a hi cut filter - stopping any stray current travelling down the cable, especially on the screen.
Near where I live is a very powerful, old fashioned pager system - lifeboat callouts and a few other users. Most people living local to it have filters on their audio and video gear, TV antenna cables - that kind of thing. Strange patterns on the pictures, odd warbles on the hifi systems. Oddly, modern TV digital systems are much more immune. The interference is still there, but digital systems tend to ignore it. Even hearing aids suffer from the damn thing - it's been this way for 30 years!
Near where I live is a very powerful, old fashioned pager system - lifeboat callouts and a few other users. Most people living local to it have filters on their audio and video gear, TV antenna cables - that kind of thing. Strange patterns on the pictures, odd warbles on the hifi systems. Oddly, modern TV digital systems are much more immune. The interference is still there, but digital systems tend to ignore it. Even hearing aids suffer from the damn thing - it's been this way for 30 years!