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Old July 19th, 2010, 03:24 PM   #1
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How To Record Audio From Multiple Mics?

I, for the life of me can't capture good audio with my Canon XL1. Here is what I want to do:

Connect a wireless lavalier microphone (Shure SLX4) to my Canon XL1 (for vows), while using the on camera microphone to record ambient sound. I am not sure how to connect both microphones to get quality audio - and what should the settings be for each? I have been disconnecting the microphone and plugging the wireless into that audio input. I have a beachtek unit that is currently not working, so I need to connect to the camera. Any help/assistance would be greatly appreciated.

Thank you all in advance.

DK
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Old July 19th, 2010, 07:43 PM   #2
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Thread title changed from "Somebody help, Please!" to "How To Record Audio From Multiple Mics?"

Please avoid ambiguous thread titles. Thanks in advance.

To use the on-board stereo mic plus one or two external
mics, you need to enable 4-channel audio recording.

Go to this link:

Canon XL1 Watchdog Articles Index

...and read through all parts of XL1 Audio Step By Step. Those pages are more
than ten years old now so the code might render the pages a bit wonky, but the
text of the articles should still be easily readable.
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Old July 19th, 2010, 11:45 PM   #3
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Note that if you chose to record 4 channels on a DV tape, you are using 32K sampling rate and 12-bit sample depth. You might want to test this mode to see if it is acceptable for the kind of production value you deliver. I can tell you that in audio circles, 32K/12-bit is completely discredited. Many lay-people with no audio experience can easily hear the difference (prominently increased distortion) between 12-bit and 16-bit (which is the "standard" DV sample depth). You might get away with this for dialog in a noisy reception, but it will be quite obvious during quiet and exposed speech (such as vows, etc.)

The 32K/12-bit audio samples will have to be trans-coded up to 48K/16-bit for editing. Some transcoding software is better than others, so be sure to include an end-to-end test including all the audio and video conversion steps.

Furthermore, be sure your workflow allows you to capture all four channels of audio from the tape. Most DV hardware and software doesn't support the 4-channel mode since it is almost never used (because of the reduced quality.)
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Old July 20th, 2010, 07:50 AM   #4
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How To Record Audio From Multiple Mics?

Thank you both for the info. Chris, I read the articles, though it all seems to all run together. Is there a simple way to use the on camera mic and connect a lav to the XL1? I really don't want to get into recording at a lesser quality rate and have to do things in post. I must be missing something simple. The articles give you many scenarios, I just need my request simplified.

Thanks again for all of your help!

DK
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Old July 20th, 2010, 08:39 AM   #5
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Hi Doug,

As I said in a previous post, in order to use the on-board stereo mic
plus one or two external mics, you need to switch your XL1 settings
to 12-bit four channel audio recording. That's the only way you're
going to be able to record audio from the stereo mic (two channels)
plus one or two additional channels from other mics.

Just follow these step-by-step directions on this one page...

XL1 Audio Step by Step, Part Four provided by Canon USA

Excerpt: "the exact procedure for 12-bit four channel audio recording is
carefully outlined, along with instructions for monitoring four channel audio
through the headphones. This is pretty much the same description found
in your XL1 owner's manual, except the layout here is, in my opinion,
much more clear."


If you don't want to record 12-bit four channel audio on the XL1, then
your alternative is to record 16-bit two channel audio from the stereo
mic alone, and record additional mics separately using a standalone
audio recorder. During editing you'll have to sync the XL1 audio
racks with those of the separate audio recorder.

You could also replace the onboard stereo mic on the XL1 with a
mono mic, which will free up one of the two available channels in
16-bit mode, allowing you to also record an input from another mic.

Basically:

The on-board stereo mic requires two audio channels. In 16-bit
mode, those are the only two channels you have. If you want
the stereo mic plus another mic or two, then you must use
the 12-bit four channel mode.

If you want to stay in 16-bit two channel mode, then you must
replace the stereo mic with a mono mic in order to free up a
channel for the wireless lav.

Also, the XL1 is a twelve-year-old camcorder. The Canon
XL H1A / H1S of today, along with the XH A1S / G1S and
the new Canon XF 300 / 305, all allow you to switch the
onboard stereo mic to mono to accommodate the exact
situation you're describing. Unfortunately the stereo mic
included with old XL1 doesn't have this capability.

Hope this helps,
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Old July 20th, 2010, 10:51 AM   #6
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As Chris noted, in order to easily record an on-board mic and a wireless signal and still maintain higher quality 48k/16-bit audio, you need to use a different mic than the Canon stock stereo mic. That mic is not only stereo but also had a built-in power connector which makes adapting it to mono more difficult.

The new mono mic should be either self-powered or require no power (dynamic) and should be adapted to connect at whichever set of connectors that can also accommodate your wireless receiver.

Usually it's easier to connect both devices at the rear RCA connectors and make sure you have all your settings correct.

Depending on how you mount and connect the new mono mic, you can also leave the original stereo mic in place so it's ready to go for run-and-gun stereo with only a couple of switch changes. Or you can completely replace the stock mic and use the camera's mic holder but that often requires adding some padding to the diameter of the new mic. I used a small section of thin mousepad wrapped around thinner mics for this.
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