Sony portable recorder + lav = wireless mic

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rungunshoot

I don't know how popular a technique this has become, but I've been using portable recorders + lavs instead of RF wireless mics for over a year now. I use a Sony ICD-SX712u portable recorder and a lav mic that came with my Sennheiser G3 kit.

I just plug the lav mic into the recorder, mic the talent as usual, and sync it up in post with FCP X.

This eliminates the hassle and expense of a full wireless system, you don't have to deal with radio interference, and you have unlimited audio channels. The only main drawback is the inability to monitor sound as it's being recorded. But so far I've had really good results just by carefully mic'ing people beforehand.

I've done a blog post which details exactly how to set up and use this system:

http://rungunshoot.com/diy-wireless-mic-lav-mic-portable-recorder-diy-belt-clip-holster/
 
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I just carefully tape down the microphone and keep a visual check on it - I can usually see if it's rubbing on something, in which case I stop the action and correct the mic placement. I've gotten used to paying extra attention to mic placement, and so far I haven't had many issues with un-monitored audio problems. And whenever there's a pause in the action, I have the talent pull out their recorders so I can do a quick visual check of the recording levels.

I actually had more audio issues with RF mics because the talent would wander too far from the receiver and introduce static, or I would fly to a new city and discover my RF frequencies were occupied.
 
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But you do not know until the take is completed - and you have auditioned the audio - if there were any problems. Are you suggesting that the audio be auditioned on the set after every single take? That means removing the recorder from the talent, plugging headphones into the recorder unit, auditioning the audio, making a decision, unplugging the headphones, making sure that the previously recorder audio is not erased, replacing the recorder on the talent. Seems overly cumbersome to me, and wastes a lot of set time. I guess that it would be okay for no budget projects in limited circumstances, but as a regular process??????

Way back when I did production sound I never had problems with "the talent would wander too far from the receiver" because I would use decent quality wireless (Sennheiser or Lectrosonics) with fresh batteries and would strategically place the receivers. I've never had a situation where the talent got beyond 100 unobstructed yards (300 feet) of the receivers, which is about the effective range of quality wireless systems.


BTW, 44kHz does not exist as stated in your article, it's 44.1kHz. Also, sound for picture standard is 48kHz, so there is always the possibility of sync problems if the conversion from 44.1kHz to 48kHz is not handled correctly. If the recorder has the option you should also use the 24 bit setting for the additional headroom, and 24bit does not use any additional data space.
 
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I neglected to note that I'm shooting mostly docu-verite or "reality TV" style footage. My job is to go out to location solo and capture on-the-fly verite footage of highly unpredictable subjects. So issues like talent wandering too far from the camera become very real.

So in my work, there are no "takes" per se. I usually don't listen to the audio until the end of the day (this might be too risky for some people). I just take a visual look at the audio meters periodically to make sure the recorders are still rolling.

I have experienced drift in the sync between two extended takes, but in my research it seems this is an issue with any audio sources running on separate clocks. Not sure if it's a 44.1kHz vs 48kHz issue.

So I'm not sure how viable or necessary this technique is for low-budget narrative work, but it's certainly made my job easier.
 
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I'm doing this too with the h4n and rode pinmic on my upcoming feature -- I don't hope to have to use any of this audio, but my thinking is it'll be a last resort in case my shotgun fails on every take for whatever reason.

The other downside is the h4n is a little bulkier than a wireless system. The plan is to have it in a jacket pocket or a purse, or planted in the scene somewhere.
 
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If the recorder has 2 or more channels, what you can do is use those extra channels to protect going over by using resister or positioning of mic or fabric over it to pad the db of the sound down . This way if the master has noise that is too loud (over the threshold of the recorder set gain level) then another mic will hear the.sound at a lower level and the recorder can record that.
 
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I've thought about using a safety channel, but I'd need a stereo lav, and the ones I've seen seemed kind of bulky (like the Giant Squid models). Anyone know a good stereo lav for this kind of application?
 
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rungunshoot said:
I have experienced drift in the sync between two extended takes, but in my research it seems this is an issue with any audio sources running on separate clocks. Not sure if it's a 44.1kHz vs 48kHz issue.
Click to expand...

You should be using 48kHz and 24bit, although neither of these settings will help with the sync issue. There is only one cure for the sync issue and that is to lock the audio recorder and the camera to the same clock source. The longer your takes, the more drift you will get, the more work you'll have to do to get it back in sync and the more this is likely to degrade the quality of the dialogue.

rungunshoot said:
I've thought about using a safety channel, but I'd need a stereo lav, and the ones I've seen seemed kind of bulky (like the Giant Squid models). Anyone know a good stereo lav for this kind of application?
Click to expand...

You wouldn't use a stereo lav, always try to avoid recording dialogue in stereo. Use a mono lav but route the lav's input to both channels of the recorder. Then, one input on the recorder would be set about 10dB lower than the other, so if the higher channel clips the lower channel provides a safety. For this to work you obviously need a recorder that has this internal routing functionality or a mixer.

G
 
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Can easily cut cables and rewire up.
My sony pcm d50 only has 2 channels and a single gain control. can not db pad a single line with the device directly.
I have made a connector that allows 2 different microphones to be wired into the device via a single mic input, the first time I made this connector i had a lot of noise, but 2nd go worked.
This allows 2 mics, so can easily connect 2 lavs.
Also could db pad a single mic line or put 2nd mic in location on body where talking produces less volume as back up. when audio is clipped then can use backup line recording. this plus that the device has a gain reduction on clipping makes for an even bigger margin for making sure manage to record audio.
 
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it's an interesting 'if all else fails, back up against a wall' solution but definitely not a replacement for radio mics. First thing that springs to mind is getting audio on a rollercoaster ride with a pencil cam that can't take audio.
Then again I don't have the eyes of a hawk to notice the slightest brush against the mic, especially when the subject has wandered off over 100 yards away. With x-ray vision you could also use this technique with concealed mics too :D
 
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