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Roll off & attentuate on mic capsule or on mixer/recorder?

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Min Shen
Roll off & attentuate on mic capsule or on mixer/recorder?
on Feb 10, 2009 at 2:12:09 pm

Hi everyone,

quick question - if there's a need to roll off bass (low cut) or attentuate (-10dB) on my microphone, should I do it on the microphone or on the mixer/recorder????

assuming all equipment are professional quality.

Thanks!


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JC Boulay
Re: Roll off & attentuate on mic capsule or on mixer/recorder?
on Feb 10, 2009 at 5:55:37 pm

In general, you should address those issues before hitting the preamp, on the mic itself.

JC Boulay
Audio Z
Montreal, Canada
http://www.audioz.com


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Brian Reynolds
Re: Roll off & attentuate on mic capsule or on mixer/recorder?
on Feb 11, 2009 at 7:30:18 am

It would depend on the mic, why you wish to roll of the bass?, can you monitor the mixer with good Headphones/ speakers?

If you were doing quick news work or working in HIGH winds then roll off at the mic.
If you were doing doco or commercial work I would tend to do it at the mixer, as most mixers have normally have several settings, this way the problem noise can be dealt with and not removing to much bottom end.
Roll off can be a problem these days as most people are viewing / listening on much better sound / speaker systems and if there isn't the right amount of bottom end your product will sound thin and annoying compared to other programs.
Ocassionally compare your product with others produced by different people.


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Min Shen
Re: Roll off & attentuate on mic capsule or on mixer/recorder?
on Feb 11, 2009 at 1:29:21 pm

Hi and Thanks so much to everybody's reply.

I guess the main reason I would wanna roll off would be for AC and electrical hum. So do you think I should still roll off on the mixer instead?

Besides roll-off, what about attenuation? I understand if it's extremely loud volumes on location, then it would be best to attenuate straight on the mic to prevent the diaphragm from too much vibration and distortion, so I should definitely attenuate on the mic first, is this correct?



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Brian Reynolds
Re: Roll off & attentuate on mic capsule or on mixer/recorder?
on Feb 12, 2009 at 7:49:32 am

The roll off on the mic will have no effect on induced AC / electrical hum as this gets into the cable between the mic and the mixer.(but the roll off on the mixer might help with this problem)
A better way to get over induced noise is keep the audio cables at least a metre away from power cables, and if you need to a cross power cables do it at 90 degrees as this will stop induced hum from that point.
If you need to buy audio cable for you kit I would recomend the use of "starquad" type cable.
I prefer Canare L-4AE5C as it will reject hum and buzz, it is also 4.8mm Dia rather than the normal 6mm cable which means its takes up less room in your bag.
You would need to use the attenuation only on super loud sounds (people shouting, Race cars etc.) But if it is that noisy use a dynamic mic they are more robust with less potential problems with the high signal levels.
I hope this helps....



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Rodney Morris
Re: Roll off & attentuate on mic capsule or on mixer/recorder?
on Feb 12, 2009 at 1:44:42 pm

All suggestions here are good thus far. Brian, when I read Min's post about AC hum, I read air conditioning hum, in which case the mixers HPF would work to cut down on. Many mixers have variable HPF settings (some continuously variable) and work well for low level audible (not induced) hums and what not. However, not all clients want you to roll off the low end. I've done a lot of live shots where the studio didn't want me to roll off the low end, even though it gets rid of pesky background noises but doesn't really affect the voice reproduction.

Freelance Sound Technician/Mixer


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Ty Ford
Re: Roll off & attentuate on mic capsule or on mixer/recorder?
on Feb 14, 2009 at 3:11:07 pm

Welcome to the Cow Audio Forum MIn,

Rodney and Brain have given some excellent advice.

Controlling high volume sound as early as possible in your chain is a good idea. If your mic has a 10 dB pad use it. If it doesn't, then you trim at the mixer or at the camera. At some point, however, a microphone's capsule may be overloaded. If it is, no amount of downstream adjustment will work.

Some modular mics offer the ability to change capsules. Of these, a few have attenuation modules that can be placed inbetween the capsule and the body. This keeps the output of the capsule from distorting the rest of the mic's electronics. But, again, if the capsule is distorting, there's isn't much you can do.

Some builtin mic pads are put inbetween the capsule and the impedance converter. Others are put after the converter. If you have a mic with a pad that comes after the converter and the capsule is overdriving the converter, you can't escape distortion.

Low frequency roll off, sometimes call high pass, vary on different mics. Again, some high end modular systems offer a pad between the capsule and the impedance converter. This keeps the impedance converter and other downstream parts from having to deal with LF junk.

I always try to err on the side of caution and not take too much off, leaving some of the work for the folks in post. As mentioned, once you've scraped it off, there's no putting it back.

Regards,

Ty Ford






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






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