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Blackmagic Video Assist Audio and BMPC

PostPosted: Fri Mar 09, 2018 2:00 am
by SFCHUD
I am trying to figure out the workflow for recording audio for narrative filmmaking. I am shooting with BMPocket.

I am using Blackmagic Video Assist and would like to use an external mic to record audio to the card in the video assist.

I have a Sennheiser K6 Combo (Shotgun Mic with Boom.

I also have a Tascam D-40 recorder.

Can anyone tell me the workflow using these or similar setup?

My head is telling me to record actors audio using the Sennheiser K6 Combo Boom Pole while running it through the Tascam D-40 and then into the Blackmagic Video Assist?

Is this correct? I found XLR cables on the Blackmagic site, but they are very very short. I have an XLR cable for the Boom Pole and Mic that is super long. It is an older cable, however.

Hopefully, this makes sense.

I am open to entirely new suggestions and workflow that I am not aware of. My goal is essential to get as professionally recorded sound from my actors and get the recorded audio onto the scandisk inside the Video Assist.

My head is going to explode now.

Thanks!

Re: Blackmagic Video Assist Audio and BMPC

PostPosted: Sat Mar 10, 2018 12:36 am
by Denny Smith
Is the Video Assist the 4K model? If so, it has a balanced mic/line input that you could just connect the Mic to the VA4K. You will need the short adapter cables, as the VA is a Mini XLR connector, and the mic cables are usually full size XLR connectors. If the Tascam has a balanced line out (TRS or XLR), then you could connect the mic to the Tascam and connect the Tascam line out to the VA, and set the VA to line level input (instead of Mic input), this way you get two audio recordings. I would record a scratch track on the Pocket camera (BMPCC) also to help with audio sync and use a clap board at the start of yiur takes.

Cheers

Re: Blackmagic Video Assist Audio and BMPC

PostPosted: Sun Mar 11, 2018 8:36 pm
by Erkki Juurus
I'd probably do just a simple dual audio solution, using the audio recorder as a standalone recorder connected only to a mic, and then sync the audio track in post.

I might also use another mic plugged straight into the Video Assist for another audio track. That way you could capture a slightly different audio track, or a decent quality backup track, and still keep things pleasantly simple with minimum hassle.

Re: Blackmagic Video Assist Audio and BMPC

PostPosted: Mon Mar 12, 2018 2:50 am
by Denny Smith
Sounds like a good plan... :roll:
Cheers

Re: Blackmagic Video Assist Audio and BMPC

PostPosted: Mon Mar 12, 2018 1:13 pm
by Brad Hurley
One note on this: the video assist has a cooling fan inside that often runs when recording; I only have the small video assist not the 4K (and only just got it yesterday), but when I was making some test recordings with it the fan came on a few times; it's quite audible even after applying the most recent firmware updates (one of the updates back in 2016 included improvements to reduce fan noise).

Bottom line: be sure your mics are far enough away from the camera that they don't pick up the fan noise.

Re: Blackmagic Video Assist Audio and BMPC

PostPosted: Tue Mar 20, 2018 11:31 pm
by SFCHUD
Thank you for the replies.

I currently have it set up, XLR mini adapter to XLR cable which is attached to a mic.

I finally started getting audio to run through BMVA but also experienced massive feedback and peaking .....

I panicked and turned off the BMVA.

Hmmmmmmmmmmmmm .... any insights?

Re: Blackmagic Video Assist Audio and BMPC

PostPosted: Wed Mar 21, 2018 10:26 am
by Brad Hurley
SFCHUD wrote:I finally started getting audio to run through BMVA but also experienced massive feedback and peaking .....


The 4K BMVA has speakers, which are supposed to turn off automatically when recording and monitoring to avoid feedback. Sounds like that may not be happening in your case? Is there a way to turn off the speakers manually and see if the feedback continues?

See page 17 of the instruction manual:

http://documents.blackmagicdesign.com/V ... Manual.pdf

One other thought: You're using your Sennheiser K6 mic, correct? Are you using it with the internal batteries to supply phantom power? If so, be sure phantom power is NOT turned on in the video assist. You can supply phantom power with the video assist, but if you do that be sure you're not also using the batteries on the mic to supply phantom power. Use one or the other, not both at the same time. See page 22 of the instruction manual linked above. My guess is that this is what's causing your distortion and peaking; I hope you didn't damage the mic.

Re: Blackmagic Video Assist Audio and BMPC

PostPosted: Wed Mar 21, 2018 5:04 pm
by Denny Smith
Good point Brad, I forgot bout the speakers on the VA4K, that would also likely cause feed back.
Cheers

Re: Blackmagic Video Assist Audio and BMPC

PostPosted: Wed Mar 21, 2018 5:24 pm
by Brad Hurley
Denny Smith wrote:Good point Brad, I forgot bout the speakers on the VA4K, that would also likely cause feed back.
Cheers


In this case, though, I bet it's not the speakers (which are supposed to shut off during recording and monitoring), but more likely the effect of having phantom power turned on in the VA and also on this particular microphone, which comes with a battery unit to supply phantom power. The combination would very likely lead to distortion and peaking, and could damage the microphone.

Re: Blackmagic Video Assist Audio and BMPC

PostPosted: Wed Mar 21, 2018 6:33 pm
by Denny Smith
Also a very good consideration. However, I have the same K6 mic setup, with several heads, including the ME66 shotgun, and have made the mistake of leaving the battery in and turning on Phantom power, given the choice the K6 switches to the Phantom power and does not draw from the battery. When powering from both (by accident, I normally remove the battery when using Phantom power), I did not get any feedback or distortion. The mic actually performs better with Phantom power from my observations.
Cheers

Re: Blackmagic Video Assist Audio Only?

PostPosted: Tue Apr 24, 2018 6:56 am
by surfware1
Does anyone know if there is a way to use the BMVA as a standalone audio recorder? It currently can't find the source.

Wondering what settings I am missing or how to do?
Thanks!

Re: Blackmagic Video Assist Audio and BMPC

PostPosted: Tue Apr 24, 2018 5:49 pm
by Tony Rivera
The Video Assists cannot be used as an audio recorder. Audio would need to be embedded to a video feed in order to be recorded on the device.

Re: Blackmagic Video Assist Audio and BMPC

PostPosted: Wed Aug 08, 2018 8:31 pm
by asparagui
I would like to record the video stream (from my laptop) and then record audio over it. I bought an XLR cable to plug in my AT mike using phantom power, but it requires a ton of gain (like +50db) and sounds terrible. Are you saying I this isn't a supported route, or am I misconfiguring things somehow?

Re: Blackmagic Video Assist Audio and BMPC

PostPosted: Wed Aug 08, 2018 8:45 pm
by Tony Rivera
Brad references page 17 of the Video Assist Manual earlier in this thread with some relevant information for expected audio ingest to the product to help achieve ideal recording levels. We'd suggest looking over this to see what will be needed for your setup.

Re: Blackmagic Video Assist Audio and BMPC

PostPosted: Thu Aug 09, 2018 4:31 pm
by asparagui
Yes, I've got things configured properly. Did audio for a few years back in the day.

I guess my hope was to use this setup to record audio without having a mixer/booster in the loop, but it's currently not looking like that is the case. Is that a correct expectation?

Re: Blackmagic Video Assist Audio and BMPC

PostPosted: Thu Aug 09, 2018 5:25 pm
by Denny Smith
I think using a mixer is the best way to go, much better preamps, and more control. A used Sound Devices MixPre would do the trick, and has excellent amps.
Cheers