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Weird distortion with Sennheiser ME2 lav

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Jack Beattie
Weird distortion with Sennheiser ME2 lav
on Jan 8, 2020 at 10:09:29 am

I recently upgraded to the Sennheiser AVX kit with the ME2 lav which runs straight into my Canon C100.

I've noticed the microphone has a strange distortion with audio where it sounds like the audio is clipping on some dialogue, even though the levels are usually around -15 to -20db, this remains consistent across multiple shoots with different talents.

I've found I'm able to fix this when I take the audio in to Audition and use the DeClicker effect which removes most of the artefacts, but I don't always edit my own projects and it isn't a good look to have this distortion in my clients videos.

I'm wondering if anyone has heard of a problem like this? I am definitely mounting the mic correctly. Maybe I have a faulty transmitter or receiver and I need to speak to Sennhesier?

I'm happy to provide an example of the audio to help diagnose the problem.

Thanks!


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Ty Ford
Re: Weird distortion with Sennheiser ME2 lav
on Jan 10, 2020 at 5:00:54 pm

Hello Jack and welcome to the Cow Audio Forum.

Hmm. AVX. that's a 1.9 GHz system.

Yes, can you please post a sample?

Regards,

Ty Ford
Cow Audio Forum Leader

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford's Blog


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Jack Beattie
Re: Weird distortion with Sennheiser ME2 lav
on Jan 11, 2020 at 3:31:14 am

Hi Ty,

Thanks for your reply. You can find an example of the noise below.







You can hear the clicking sound on some words, I still don't know what could be causing this as it is a new unit and I manually control the gain to peak around -15db.

I don't think it's a microphone mounting issue either as I get the same sound problem on multiple shoots.


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Ty Ford
Re: Weird distortion with Sennheiser ME2 lav
on Jan 11, 2020 at 2:55:43 pm

Hi Jack,

What I'm hearing is peak clipping. Could be that whatever you're metering with is measuring RMS instead of Peak.

Possible?

When you bring it up on the time line, can you zoom in enough to see the peaks?

If it's clipping well below peak, then perhaps some gain staging issue, e.g. between the mic and the transmitter...a sensitivity adjustment or between the transmitter and receiver.

Regards,

Ty Ford
Cow Audio Forum Leader

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford's Blog


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Jack Beattie
Re: Weird distortion with Sennheiser ME2 lav
on Jan 12, 2020 at 9:48:12 am

Hi Ty,

I've had a look at the audio in the timeline and highlighted it. The peak amplitude of the raw audio is at -19.9db and most of the dialogue sits at around that point.

I'm not an expert but maybe there is either a problem with the mic or the transmitter? There are no gain controls on the AVX system so maybe my best bet is to send it to Sennheiser to see if they can diagnose the problem?

Very odd...

Thanks.


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Ty Ford
Re: Weird distortion with Sennheiser ME2 lav
on Jan 12, 2020 at 4:10:21 pm

Hi Jack,

Do you have another device you can try the AVX with?

Does the AVX offer line or mic level out?

I THOUGHT that Line level on what was a 'pro" camera should have been. I have seen situations in which the line input of a device (camera) is called line level, but it's -10 line level and not 0 or + 4. The PD150 and PD 170 video cameras were like this. My mixer has mic, -10 and line output switching.

When I switched to calibrating mic level out and went mic level in to the camera, the problem disappeared. After I figured that out, I also tried switching the mixer to -10 level out and calibrating to the camera. It worked just fine.

Do you have that capability?

Regards,

Ty Ford
Cow Audio Forum Leader

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford's Blog


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Jack Beattie
Re: Weird distortion with Sennheiser ME2 lav
on Jan 15, 2020 at 9:23:47 am

Hi Ty,

Unfortunately I just sold my old Tascam audio recorder.

There is an AF Out button on the receiver of the AVX where you can adjust the dBu in increments of 10dBu.

Mine was set at the lowest setting of -30dBu and it can go up to 0dBu if needed. The camera itself has the Mic +48v setting selected for the channel but also has Mic and Line options.

I wonder if it is worth playing around with the receiver's gain or switching to a line input?

Thanks again.


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Ty Ford
Re: Weird distortion with Sennheiser ME2 lav
on Jan 15, 2020 at 2:04:10 pm

What are the Mic/Line options on the camera?

Regards,

Ty Ford
Cow Audio Forum Leader

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford's Blog


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Jack Beattie
Re: Weird distortion with Sennheiser ME2 lav
on Jan 15, 2020 at 11:57:31 pm

For the XLR inputs there are 3 options. Line, Mic and Mic +48v.

For the AVX I usually leave it on Mic +48v.


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Ty Ford
Re: Weird distortion with Sennheiser ME2 lav
on Jan 16, 2020 at 12:38:26 am

Jack,

Unless the AVX specifically states that it want Phantom Power, I'd turn it off.

What about the ones on the camera?

Regards,

Ty Ford
Cow Audio Forum Leader

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford's Blog


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Jack Beattie
Re: Weird distortion with Sennheiser ME2 lav
on Jan 16, 2020 at 12:50:20 am

Hi Ty,

Sorry I meant that the camera was the one with the controls for Line, Mic and Mic +48v not the AVX itself.

From what I can gather the purpose of phantom power with the AVX is that it can turn itself on when the camera is switched on and it is designed to do this.

It can't hurt to try it out with just Mic settings through the camera or even trying the line switch and seeing how that effects the audio?


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Ty Ford
Re: Weird distortion with Sennheiser ME2 lav
on Jan 16, 2020 at 12:53:13 am

Well you have a level problem somewhere (or something else) that's clipping the peaks of your audio. Try line level on the camera input and make some test recordings.

Regards,

Ty Ford
Cow Audio Forum Leader

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford's Blog


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