Electrical background buzz

Skargill · Post by **Skargill** » June 21st, 2017, 2:53 pm

Hello everyone, I have a problem, when ever I record there is a very prominent and constant background hum, I can limit it with noise removal, but its always there unless I lower the volume to below the accepted DB range. I'm using a samsung Q1U desktop microphone. I've tried switching everything off and running on battery power (not ideal for long recordings) but the noise persists.

Is there a microphone setup thats well known for cancelling out this problem? This issue adds a lot more editing work to my recordings and sometimes I had to clean it up so much that my voice track started to distort.

Post by **annise** » June 21st, 2017, 3:02 pm

It could be a mains current hum which can be removed easily with a notch filter . If you are using Audacity plot the spectrum and see if there are definite peaks at say 60, smaller at 120 etc, with the 60 varying according to your local mains supply.

Anne

Post by **TriciaG** » June 21st, 2017, 3:06 pm

If you don't know how to plot the spectrum, upload a few seconds of the hum and post the link here, and we'll take a look.

Another thing: Put a piece of foam or a thick, folded cloth under your microphone. This will help absorb vibrations from the desk and help the mic to not pick them up.

Skargill · Post by **Skargill** » June 22nd, 2017, 9:21 am

annise wrote:It could be a mains current hum which can be removed easily with a notch filter . If you are using Audacity plot the spectrum and see if there are definite peaks at say 60, smaller at 120 etc, with the 60 varying according to your local mains supply.

Anne

I'm afraid I don't know what means but the buzz does have an electrical sound.

TriciaG wrote:If you don't know how to plot the spectrum, upload a few seconds of the hum and post the link here, and we'll take a look.

Another thing: Put a piece of foam or a thick, folded cloth under your microphone. This will help absorb vibrations from the desk and help the mic to not pick them up.

https://librivox.org/uploads/tests/buzz.mp3

I've amplified it, this is what it sounds like at around 60 db without noise removal. I've also taken to holding my microphone in one hand while recording, I hoped distance would help but I don't think it has.

SkyRider · Post by **SkyRider** » June 22nd, 2017, 9:29 am

I had a Q1U some time ago and it was extremely noisy - if I turned up the noise reduction enough to get a clear background my voice distorted to sound bubbly.

This was mitigated a bit by having the mic closer when I spoke so there was more voice to background then using less noise reduction. In the end though I ended up having to change microphone. I've only ever heard others say good things about the Q1U so assumed that mine was a one-off poor copy but your hiss sounds remarkably similar.

Cheers,
Paul

Post by **TriciaG** » June 22nd, 2017, 9:33 am

I've got a Samson Q1U, too, and it doesn't make nearly as much noise.

This is general static, not a mains hum. It's over a broad spectrum of frequencies, not peaking at 60 Hz.

mahne · Post by **mahne** » June 23rd, 2017, 12:14 am

Hi Skargill,

What do you mean, you have amplified it? Why and how much? Can you upload a raw recording, having both silence and your voice?
And the first ~50 ms of your recording seem to be fine, do you or anyone else have an idea why that could be?

Cheers
mahne

Skargill · Post by **Skargill** » June 23rd, 2017, 10:00 am

mahne wrote:Hi Skargill,

What do you mean, you have amplified it? Why and how much? Can you upload a raw recording, having both silence and your voice?
And the first ~50 ms of your recording seem to be fine, do you or anyone else have an idea why that could be?

Cheers
mahne

Well not really no you wouldn't hear anything at all if I didn't amplify it. That's the problem to get an acceptable volume for a recording means the buzz becomes over bearing needing a lot of noise reduction. I can record without a buzz but my recordings will be rejected for being too quiet.

SkyRider · Post by **SkyRider** » June 23rd, 2017, 10:07 am

How far away is your mouth from the microphone when recording? With most small dynamic microphones you generally need to get pretty close (as in inches away).

[Also, ignore my earlier comment - I was getting the Samson model numbers confused. It was a C01U I had the noise issues with).

Cheers,
Paul

(Edit: Youtube to the rescue! This is how close you need to get to a dynamic mic.)
(Re-edit: Sorry - it would have been helpful to include the link)

mahne · Post by **mahne** » June 26th, 2017, 12:12 am

Skargill wrote: Well not really no you wouldn't hear anything at all if I didn't amplify it.

Then I think we found the problem, you need to have your input gain so high that the last amplification step to get into our accepted range is only a little step (15dB max I'd say). Some people even record with their input gain so high that they need to de-amplify to get in our range. The reason is the SNR, signal-to-noise ratio. The louder your voice comes into the raw recording, the less the noise will make problems.

One possibility is to get closer to the mic (some say max 15 cm away, some say 1-2cm), another one is to increase the input gain slider in audacity (slider right to the microphone item), a third possibility is to search in your computers setting, there might be another slider or "boost" button thing in your system settings.

Try to get as near as possible to the loudness goal with the raw recording.

Hope that helps
mahne

Skargill · Post by **Skargill** » July 2nd, 2017, 7:38 am

I've done what you've suggested, the noise is still there at higher gains but noise removal seems to be easier to deal with so far.