Sound Problems on the BMCC

We have had the unique pleasure of having two BMCC delivered however the pleasure ends there. The first unit arrived on the first day of a five day drama shoot so we had not time to bench test the unit. After the end of the first day we found an problem on the audio input stage of the camera. With our Wooden Camera A box XLR adapter plugged in but no other audio connections there was a noise floor of -31.9db peak on Ch 1 and -34.7db peak on Ch 2 with the camera input level set at 59%. We sent of various Pro Res clips to the nice man at BMD in the UK and he concluded there was a fault with the unit and we should return it. Very swiftly a new unit landed at the studio and with shaking hands we loaded it into our Shape rig, plugged in the jack plugs, ran BM Ultrascope and the same problem presented its self! We ran a few further tests in the Pro Tools suite and discovered that if you wished to line up the audio in the camera with PPM4 from a Sound Devices mixer to a true -18db the input levels on the BMCC needed to be set at Ch1 68% and Ch 2 73%.

So to all you happy BMCC users out there have you seen problems such as these? When recording audio to camera what camera levels have you used to line up PPM4 tone at line level into the camera? Any thoughts on our problem?

Max

You might want to check out this video.. go to about 5 minutes and they talk about the best settings for cleaner audio on the BMCC. to sum it up.. you should set your input levels between 20-30%.

I hope this helps.

...or you could buy a Tascam DR40 for $150 and call the problem solved.

Hi Rich

Thanks for the info but we can't get our BMCC audio to line up at -18db using a PPM 4 tone signal at anything under 70% camera level.

Max

Hi Philip

The Tascam has its own issues and is a poor audio recorder. We are using two boom mic's + three radio mics on drama shoot so we need to record on camera sound via a Sound Devices mixer. The point is the BMCC should be able to record high quality audio and not require more add on's to function correctly.

Max

... So to all you happy BMCC users out there have you seen problems such as these? When recording audio to camera what camera levels have you used to line up PPM4 tone at line level into the camera? Any thoughts on our problem? Max

The audio settings I used for my "first" BMCC video are described on the Vimeo page:


The audio in the edit is straight from the camera, as recorded. I don't consider my findings to be the last word on the topic, but the above are settings that yielded OK results for me. Let me know what you think.

Hi Rich

Thanks for the info but we can't get our BMCC audio to line up at -18db using a PPM 4 tone signal at anything under 70% camera level.

Max

Here is Peter's approach that gave good results:
"Sound: Recorded in-camera using a Sennheiser ME64 mic through a SoundDevices MixPre preamp. The line level output of the mixer was recorded by the BMCC set to "Line level", with input levels set at 85%, and the BMCC's internal mic set to 0% (off). Using these settings, the MixPre's test tone plays @ -18db in FCP7."

Rick Lang
Sent from my iPad using Tapatalk HD

Hi Rick,

Thanks for your reply.

Were both channels set to 85%?

When you put the the rushes into FCP 7 were both channels an equal level on the meters?
Q
Thanks

Max

Hi Max: For the video shoot I linked to above, my mic, mixer & camera connections and settings were different from yours, which may explain the different results. For example, I didn't test 2 mics recorded into separate camera audio channels.

I connected 1 microphone to my MixPre. I connected 1 line output of the mixer to input 1 on the BMCC. I set the BMCC's audio settings to "Ch 2 uses Ch 1 Input". Set "Channel 1 and Channel 2 Input Levels" to "Line". Set "Channel 1 Input" to 85% (the camera set both Ch 1 & Ch 2 to 85%). Set the camera's "Microphone Input" (the internal mic) to 0% (off).

I hope this helps.

I shot a commercial shoot the other day with the BMCC and the Wooden Camera Cage rig with the XLR adapter and worked fine.

We had a audio guy with us and used Ultrascope to check our incoming tone level. Camera was set at 40% input at line level direct from his mixer. Really happy with the rig and the audio setup!

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Hi Todd

Thanks for the info. You were using a similar audio set up as us but we are having to use totally different settings on the camera to achieve the same results.

Max