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Can someone tell me what is wrong with my sound?

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Eoin Ryan
Can someone tell me what is wrong with my sound?
on Dec 30, 2008 at 2:20:34 am







I've been shooting weddings for years. Never had a problem with sound. If I can't tune into the venues microphone I will attach my own Sennheiser wireless mic and that will transmit straight to camera.

I was doing a wedding two nights ago. I tested the audio before the speeches, looking for anything strange, and everything was fine.

Father of the bride stands up to speak and, as you can hear in the link above, this strange noise started to happen.

PILOT was ON on the microphone. The hotel's mic was wired.

There were, to my knowledge, no other wireless devices on in the room.

I don't think this is interference. Is this what interference sounds like?

Very quickly, between the first and second speech, I creeped up behind the head table, and turned off my mic that was attached to the hotel's mic and attached a wireless lapel mic, on the same frequency, to the Groom and then onto the Best Man for his speech.

Nothing changed. (I popped a Zoom H2 on a mic stand in front of each speaker aswell, which picked up the sound okay from there.)

When editing, I could use the mic off the camera for audio (1st channel), but I'd really like to:

1. Know what caused the problem. What does it sound like to you?

2. Know if I can fix it with a filter. (I use Final Cut Pro 6. Shoot PAL SD 16:9 with Canon XL2. Using Sennheiser G2 Evolution or whatever they're called -- you probably know the ones.)

There was a hissing noise coming from the venues own speakers in the room, and you can hear that in the background in the clip.

I was speaking to the DJ later on and he said that wireless mics in the venue always get interference and it has to do with the lighting system in the room. He said something about electrical interference. When the lights are dimmed, it makes a sound come through the hotel's speakers (that much I can sort of understand, but then he went onto say:) and causes interference with wireless mics!?! Now, I've never heard of anything like this before.

Can someone have a listen to the clip and help me clear up this problem and suggest a possible fix. It would be much appreciated, thanks.







I need to also add that I was using the exact same microphone and receiver later that night and looking at the footage there are no problems. Used it today again. No problems.


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Will Salley
Re: Can someone tell me what is wrong with my sound?
on Dec 30, 2008 at 7:02:39 am

It sounds like crosstalk from nearby radio frequencies (police radio, TV station, etc.) and that would definitely qualify as "interference". It may very well be from some type of lighting - ballasts perhaps.

It is not uncommon to encounter, especially in larger cities, with so much RF flying around.

A way to check this would be when you hear the interference on headsets, change the transmitter/receiver frequency to something different. If the interference follows, it is more than likely a nearby source such as the light ballast or power transformer. If the interference is gone, it was most likely, another radio source.

Be sure to check your cables! Mic to transmitter, receiver to mixer, mixer to camera, for any shielding problems and faulty connections.

So far as a fix, you can try software pop/static filters but it's a random noise, which is the hardest for the software to fix. Soundtrack Pro has a good one.

Let us know what you find out.




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Ty Ford
Re: Can someone tell me what is wrong with my sound?
on Dec 30, 2008 at 10:39:04 am

Hello Eoin and welcome to the Cow Audio Forum.

I'm sorry for your pain. Try a declicker filter. It's typically used to remove clicks from old records, but the noise sounds very similar.

As to the cause; thats more difficult. If you are ABSOLUTELY sure that you listened fully before he got up to speak and that everything was really OK, then, unless the lights changed, it wouldn't be lights.

you said: Very quickly, between the first and second speech, I creeped up behind the head table, and turned off my mic that was attached to the hotel's mic and attached a wireless lapel mic, on the same frequency, to the Groom and then onto the Best Man for his speech.

Nothing changed. (I popped a Zoom H2 on a mic stand in front of each speaker aswell, which picked up the sound okay from there.)

When you say nothing changed, do you mean the noise persisted or that with no other apparent changes, the noise went away?

Regards,

Ty Ford

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






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