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My Studio Wireless Mic Noise Signal

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My Studio Wireless Mic Noise Signal

Postby mfzb10 » Mon Jun 03, 2019 3:42 pm

Hi!

I work with wireless lavabier mics. Sennheiser G3 - SK100.

I have 4 sets. They all work fine and I use one at a time. One I work with one, the rest are turned off, in a different studio.

I've been having horrible noise coming in, and for the life of me, I can't figure out its source.

Here it's a sample of the noise.

first you'll hear footsteps and THEN the noise. I uploaded it to this "audio host" so you can have a listen

https://instaud.io/3LGZ

This is quite the example, because most of the times the noise has no recognizable "pitch", like in the sample I uploaded, but it's like a wind, like little hits of white noise.

At first I thought it had to do with noise signals at the place I work, but I tried the mics in other places and some times, at random, I get the same noise... so that's not it

I did the "quick setup" several times, in each place, trying to find the best freq bank available. The Squelch is set on low. Nothing helped.

I also thought it might be the batteries (I use normal alkaline duracell 1.5volt batteries)... maybe a low battery problem... but the noise could randomly happen even with a new set of batteries with full charge... so that's not it either.


It is driving me crazy, because it can randomly appear in the middle of an important speech...

-------

Maybe some of you recognize this type of noise and could help to finally get rid of it.

Thank you all so very much!
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Re: My Studio Wireless Mic Noise Signal

Postby Mike Stranks » Tue Jun 04, 2019 9:40 am

The reason you've had no replies could be that, like me, people have gone to your 'hosting' website and then smartly backed away.

Pictures of Assange etc are irrelevant to what the site purports to be. It has the look of a 'gotcha/infection' website that far too many of us have regretted accessing in the past. Of course, it probably isn't, but I wasn't prepared to take the risk. (I didn't stay long enough to investigate, but my quick glance suggested that the page I was looking at through the link may not have been the right one to listen to the audio.)

Please host your audio on something like Google Drive or Dropbox and you may find that we'll listen to it and then offer suggestions.
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Re: My Studio Wireless Mic Noise Signal

Postby John Willett » Tue Jun 04, 2019 1:08 pm

What frequencies are they set to?

Are they set to legal frequencies?

I will not listen due to the post above - but the most likely explanation is another user on the same or a close frequency that is causing interference.
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Re: My Studio Wireless Mic Noise Signal

Postby mfzb10 » Tue Jun 04, 2019 1:10 pm

Mike Stranks wrote:The reason you've had no replies could be that, like me, people have gone to your 'hosting' website and then smartly backed away.

Pictures of Assange etc are irrelevant to what the site purports to be. It has the look of a 'gotcha/infection' website that far too many of us have regretted accessing in the past. Of course, it probably isn't, but I wasn't prepared to take the risk. (I didn't stay long enough to investigate, but my quick glance suggested that the page I was looking at through the link may not have been the right one to listen to the audio.)

Please host your audio on something like Google Drive or Dropbox and you may find that we'll listen to it and then offer suggestions.

Hello!

Thank you for the suggestion!

I uploaded it now to this audio-hosting site, which has no other things than the audio itself:

https://instaud.io/3LGZ

The other site I found by a quick google search "free audio hosting" and it was the first thing to appear.

--------

I was looking for the "edit post" button on the original post but I couldn't find it,
I'll try to change it up there.

Thank you!
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Re: My Studio Wireless Mic Noise Signal

Postby mfzb10 » Tue Jun 04, 2019 1:14 pm

John Willett wrote:What frequencies are they set to?

Are they set to legal frequencies?

I will not listen due to the post above - but the most likely explanation is another user on the same or a close frequency that is causing interference.

Hello sir,

I've uploaded the sample of the noise to a new audio host which has nothing but the audio and it's spectogram: https://instaud.io/3LGZ

They are set to legal freqs. The thing is that regardless of the specific freq bank, I've been having this kind of noise with all 4 sets of wireless mics. So that made me think that the noise could be coming from elsewhere. That and the fact that the noise appears at random, it's quick and sharp, and not just a constant white noise band.

The particular example that I've uploaded also has a recognizable pitch, which can be seen on the spectogram!
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Re: My Studio Wireless Mic Noise Signal

Postby mfzb10 » Tue Jun 04, 2019 1:19 pm

I don't know why but I can't seem to find the "edit post" button to change the link!

Am I getting to old? :bouncy:
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Re: My Studio Wireless Mic Noise Signal

Postby James Perrett » Tue Jun 04, 2019 1:44 pm

mfzb10 wrote:I don't know why but I can't seem to find the "edit post" button to change the link!

Am I getting to old? :bouncy:

You only have a 15 minute window to edit posts after you've posted. I've changed the link in your original post to the new one.
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Re: My Studio Wireless Mic Noise Signal

Postby MOF » Tue Jun 04, 2019 3:08 pm

It sounds like an RF dropout to me.
Set the squelch higher and listen for a mute to check if it is RF related.
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Re: My Studio Wireless Mic Noise Signal

Postby Mike Stranks » Tue Jun 04, 2019 3:20 pm

Thanks OP! That new site didn't cause me any anxieties!

Even before listening I suspected that it was an RF drop-out issue. The listen seems to confirm that. MOF (above) has given advice on that.

What frequencies/band are you using - VHF, UHF or 2.4GHz band? It's possible that if you're on 2.4GHz then something like a router, bluetooth device or similar could be interacting as there's a huge amount of stuff that uses that band.

Come back if tweaking the squelch doesn't fix it....

(... and in passing... most of us who use radio mics - even expensive ones! - only ever use them when there really is no alternative. The issues you're facing are all too frequent with radio mics. I don't know your circumstances of course, but if it's feasible I'd suggest adopting a cabled/wired mic
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Re: My Studio Wireless Mic Noise Signal

Postby mfzb10 » Tue Jun 04, 2019 8:33 pm

James Perrett wrote:
mfzb10 wrote:I don't know why but I can't seem to find the "edit post" button to change the link!

Am I getting to old? :bouncy:

You only have a 15 minute window to edit posts after you've posted. I've changed the link in your original post to the new one.

I didn't know! Thank you very much!

MOF wrote:It sounds like an RF dropout to me.
Set the squelch higher and listen for a mute to check if it is RF related.

First of all, thank you! now I can give a proper name to this issue! "RF drop out".
I will set the squelch to "high" then, and give it a try! thanks

Mike Stranks wrote:Thanks OP! That new site didn't cause me any anxieties!

Even before listening I suspected that it was an RF drop-out issue. The listen seems to confirm that. MOF (above) has given advice on that.

What frequencies/band are you using - VHF, UHF or 2.4GHz band? It's possible that if you're on 2.4GHz then something like a router, bluetooth device or similar could be interacting as there's a huge amount of stuff that uses that band.

Come back if tweaking the squelch doesn't fix it....

(... and in passing... most of us who use radio mics - even expensive ones! - only ever use them when there really is no alternative. The issues you're facing are all too frequent with radio mics. I don't know your circumstances of course, but if it's feasible I'd suggest adopting a cabled/wired mic

Thanks to you! the other site was terrible!
I think it uses UHF. I will go to the studio to check that out, but I think it was around 600mhz. I used the "quick setup" to find the best freq banks available.

I can't use wired mics for this client, because I need freedom of movement for the character that's being filmed.

I don't think it has to do with routers or bluetooth because the freq is not high enough.
I'll check if setting the squelch to high changes anything

Thank you very much to all of you! If I keep running into this problem, I'll post again.
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Re: My Studio Wireless Mic Noise Signal

Postby Mike Stranks » Tue Jun 04, 2019 10:18 pm

Ah video! :D

In that case I understand why you're on radio mics. I use them m'self for video when booming isn't an option... eg when there's an audience.

Are you in the States? If not, where?
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Re: My Studio Wireless Mic Noise Signal

Postby MOF » Wed Jun 05, 2019 12:21 am

I'll check if setting the squelch to high changes anything
Just to be clear, setting the squelch higher will only ascertain that it’s an RF problem, it won’t solve the problem.
Is it a true diversity receiver, those types are better at solving dropout?
Whatever type of receiver you have it’s maybe worth re-siting it to avoid the signal phase cancelling, this is more likely if there’s a lot of metal work in the building.
Also try and make sure there is a clear line of sight between the mic’ and receiver.
Check all aerials have nice and tight connections.
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Re: My Studio Wireless Mic Noise Signal

Postby Mike Stranks » Wed Jun 05, 2019 8:49 am

MOF wrote:
I'll check if setting the squelch to high changes anything
Just to be clear, setting the squelch higher will only ascertain that it’s an RF problem, it won’t solve the problem.
Is it a true diversity receiver, those types are better at solving dropout?
Whatever type of receiver you have it’s maybe worth re-siting it to avoid the signal phase cancelling, this is more likely if there’s a lot of metal work in the building.
Also try and make sure there is a clear line of sight between the mic’ and receiver.
Check all aerials have nice and tight connections.

:thumbup:
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Re: My Studio Wireless Mic Noise Signal

Postby mfzb10 » Wed Jun 05, 2019 12:52 pm

Mike Stranks wrote:Ah video! :D

In that case I understand why you're on radio mics. I use them m'self for video when booming isn't an option... eg when there's an audience.

Are you in the States? If not, where?

I think my bad english gave me away :lol: Spanish is my first language, but I live in Israel.

MOF wrote:
I'll check if setting the squelch to high changes anything
Just to be clear, setting the squelch higher will only ascertain that it’s an RF problem, it won’t solve the problem.
Is it a true diversity receiver, those types are better at solving dropout?
Whatever type of receiver you have it’s maybe worth re-siting it to avoid the signal phase cancelling, this is more likely if there’s a lot of metal work in the building.
Also try and make sure there is a clear line of sight between the mic’ and receiver.
Check all aerials have nice and tight connections.

Thank you!

I'm using the Sennheiser receiver, attached to the Sony X70 camera I use. The only thing between the receiver and the transmitter is the teleprompter, so it's pretty much a direct line with no interruptions. I used it in other environments though, and had the same problem.

Could it be something more related to specific freq banks? For instance, the wireless set I'm using has a 626-668 mhz range... but I had the same problem with all 4 sets I have... Tried every mic capsule, and every type of battery...

I'll keep on digging then!
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Re: My Studio Wireless Mic Noise Signal

Postby James Perrett » Wed Jun 05, 2019 1:11 pm

mfzb10 wrote:Could it be something more related to specific freq banks? For instance, the wireless set I'm using has a 626-668 mhz range... but I had the same problem with all 4 sets I have... Tried every mic capsule, and every type of battery...

In many places you will require a special licence to use those frequencies. Did you buy them in Israel? If not you may be transmitting illegally and there will be other legitimate users of that frequency band.
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Re: My Studio Wireless Mic Noise Signal

Postby John Willett » Wed Jun 05, 2019 1:22 pm

The Sennheiser G3 pocket receive *is* diversity - it uses one antenna on the receiver and the second antenna is the output cable - so it's very important that these are screwed in properly.

You *have* to purchace radio systemns in the country of intended use to make sure you get legal units - ALSO - it's viutal to check with the Sennheiser distributor in your country what frequencies are legal to use in your country or you run the risk of interference from legal users of that frequency.
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Re: My Studio Wireless Mic Noise Signal

Postby MOF » Wed Jun 05, 2019 1:32 pm

The Sennheiser G3 pocket receive *is* diversity - it uses one antenna on the receiver and the second antenna is the output cable - so it's very important that these are screwed in properly.
That’s unusual, if I read you correctly the length of the antenna will change depending on the length of the output cable, whereas it’s meant to be a particular length that corresponds to the frequency band’s wavelength.
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Re: My Studio Wireless Mic Noise Signal

Postby John Willett » Wed Jun 05, 2019 3:02 pm

MOF wrote:
The Sennheiser G3 pocket receive *is* diversity - it uses one antenna on the receiver and the second antenna is the output cable - so it's very important that these are screwed in properly.
That’s unusual, if I read you correctly the length of the antenna will change depending on the length of the output cable, whereas it’s meant to be a particular length that corresponds to the frequency band’s wavelength.

Ideally, yes - but that's how it's done on the pocket receivers.
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Re: My Studio Wireless Mic Noise Signal

Postby Mike Stranks » Wed Jun 05, 2019 3:24 pm

I've just had a quick look around the web... looks like the use of ANY radio device is tightly controlled in Israel.

This https://www.gov.il/he/Departments/ministry_of_communications is the place to check about permitted frequencies.

To reiterate what's been said... most countries have a set of permitted frequencies. And even those that are permitted may need a licence to use.

If you're operating in frequencies that you shouldn't be then that could well explain the apparent random drop-outs...

Here in the UK we can be heavily fined for using unauthorised frequencies. I suspect things will be as rigorous, if not more so, in Israel.

If in doubt: check!
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