Blackmagic Forum

I was recording some audio tests with the camera, and I noticed that the on-board audio on the BMCC is giving me incomparably better audio than what the Rode Videomic pro is outputting. The videomic is actually outputting a signal that is barely audible in general, and this is with mic input on the camera, and the settings cranked up and +20 DB on the mic itself. I've been using these two adapters: http://www.amazon.com/gp/product/B00009 ... UTF8&psc=1

http://www.amazon.com/gp/product/B000HH ... UTF8&psc=1

Yet I get the feeling I'm doing something very obviously wrong here. I do plan to buy a preamp in the near future, but should the audio on the rode really be that horrible without one? It's literally unusable.

Any advice would be greatly appreciated. Thank you for reading.

How are you connecting the video mic pro to the BMCC?

The BMCC has balanced input and if you use and un balanced jack it can cause the audio to drop in volume.

adamroberts wrote:How are you connecting the video mic pro to the BMCC?

The BMCC has balanced input and if you use and un balanced jack it can cause the audio to drop in volume.

I've been using these two adapters:

http://www.amazon.com/gp/product/B000HH ... UTF8&psc=1

http://www.amazon.com/gp/product/B00009 ... UTF8&psc=1

Could these be the incorrect adapters?

It's really strange. Even though I did some testing I had the same issue on a shoot today. The noise on the +20 db setting basically means that the audio I captured is trash but that was the only way I could get anything decent level-wise.

I hooked up the Rode VideoMic Pro's 3.5mm jack straight into the BMPCC. Wondering if I didn't mess up a setting (line vs mic).

Those adaptors need to be mono and not stereo I think.

http://www.amazon.com/Monoprice-Plated- ... B002NV2K20

Until I buy a pre-amp I've got the same set up... Rode Video Mic Pro and I've also got the H4n Zoom.

Yeah, I came from the Canon 5d Mark ii world. Anyway...Is is possible to use the h4n zoom to line into the BMCC via the headphone jack and use the sescom cable??

this one
http://www.sescom.com/product.asp?item=LN2MIC-ZOOMH4N

I guess the point is that everyone wants good sound (usable anyway) on the BMCC footage straight out of the camera.

Until I buy a pre-amp I've got the same set up... Rode Video Mic Pro and I've also got the H4n Zoom.

Yeah, I came from the Canon 5d Mark ii world. Anyway...Is is possible to use the h4n zoom to line into the BMCC via the headphone jack and use the sescom cable??

this one
http://www.sescom.com/product.asp?item=LN2MIC-ZOOMH4N

I guess the point is that everyone wants good sound (usable anyway) on the BMCC footage straight out of the camera.

Bump... still looking to see what I could be doing wrong. Any experience you guys may have with the Rode Videomic Pro and the BMCC is greatly appreciated.

The Rode Video Mic Pro has a 1/8th stereo mini jack. It's output is stereo (tho it;s made up of 2 mono signal). If you connect it to your DSLR it will record audio in both channels.

So simple plugging it into the jack adapters you have listed causes the left channel to cancel out the right (this is my understanding) because the input is expecting a balanced mono signal rather than a stereo signal.

You need to split the stereo signal into 2 mono signals that can then be fed to each input. This way each input is receiving mono signal and there is no 2nd signal that can cancel out the first.

I don't have my cables box with me to test but this cable should do the trick:
http://amzn.to/1hzgbMK (at under $4 it's worth a try)

The Rode VMP probably isn't driving the inputs in the cam. Fine for the DSLR but the BMCC needs a powered signal (I'm guessing!)

I hated my Rode VMP, sent it back straight away. Maybe it was faulty, I dunno but I hated the sound and it was noisy ( I had correct settings). I would advise to get a better mice in the future, something a bit more robust than the VMP which quite delicate and flimsy.

Adam's advice on the splitter is good, try that out but I do think the prob is the lack of 'apmage'. Best of luck!

Hugh

Thanks very much all. I will definitely pick up that adapter and update the thread with my results. One question though: is it a concern that that adapter does not offer balanced inputs (one ring as opposed to two)?

atmos82 wrote:Thanks very much all. I will definitely pick up that adapter and update the thread with my results. One question though: is it a concern that that adapter does not offer balanced inputs (one ring as opposed to two)?

You only "NEED" balanced if you are running long cables. Balanced cable basically carries the signal on 2 cables so that it can cancel out any noise introduced in long cable runs. As these cables are so short you should have no issues.

I'll be able to test this confiq on Sunday or Monday.

Thank you, Adam

I tested the Hosa cable adaptor this afternoon.

It works fine with input set to Mic and the mic set to +20dB. As expected the is noise and the "normal" BMCC sound quality EQ issues still exist. I had the camera set to 100% on one channel and 80% on the other.

Sound is too low with it set to 0dB.

I'll post a comparison with samples between the BMPCC and the BMCC this evening.

Grab the cable on Amazon US for $3.56 - http://amzn.to/1hzgbMK
Or Amazon UK for £3.85 - http://amzn.to/1mhEyyL

I'm going to be using the vmp pro for the first time since all these firmware updates came along, is the consensus still to use the input set to mic at 20% and mic at +20db for best SNR and no clipping?



Is the DC offset still as bad as mentioned in the JuicedLink Video ? ? :

https://www.youtube.com/watch?feature=p ... rXGEUCRS5k

Will Tejeda wrote:I'm going to be using the vmp pro for the first time since all these firmware updates came along, is the consensus still to use the input set to mic at 20% and mic at +20db for best SNR and no clipping?

Is the DC offset still as bad as mentioned in the JuicedLink Video ? ? :

DC offset was fixed a long time ago.

Here is a quick test at my desk. Mic is about an arms length away from my. It's on my desk to it's picking up some of the vibration and sound from the fan and I have builder outside making a noise but you get the idea.
https://dl.dropboxusercontent.com/u/646 ... c_test.zip

I can re-record in a better setting when the builders are done.

The problem is with those adapters,

I use the Rode Video mic pro with my bmcc and it works great, but you must use the following:

3.5mm to Balanced
http://www.amazon.co.uk/3-5mm-Stereo-6- ... o+balanced

and

3.5mm coupler

http://www.amazon.co.uk/Pro-Signal-Coup ... mm+coupler


else it will not work properly.

room 3mx5m study room with soft and hard furnishings, no acoustic panels.

Camera was 1.7m from Mic

Mic was 0.4m from subject

Mic used Rode Video Mic Pro, direct into camera via 3.5mm -> Balanced audio cable adapter. No additional preamping used. The mic is self powered and was set to a flat response and +20db gain.

The camera was set to Mic level input at 50% in camera gain.


Unprocessed:
http://tommajerski.com/downloads/Audio/ ... pcGain.wav

You only "NEED" balanced if you are running long cables. Balanced cable basically carries the signal on 2 cables so that it can cancel out any noise introduced in long cable runs. As these cables are so short you should have no issues.

Doesn't running an unbalanced line into a balanced recorder result in a -6dB drop?

Thanks for the info guys.

@Tom I ended up using one of these cables that I had picked up months ago but never got around to using.

http://www.amazon.com/gp/product/B0010D ... CPZVL7E6XQ

Rode Video Mic Pro + Splitter cable into BMCC 2.5k , no preamp

Levels set to 9% on mic level input and Mic set to +20db. Only one side of the mic plugged into Input 1 and hade the other input mimic that for a faux stereo recording.

It was a very noisy scene , I was flying a 2.5k bmcc on a Laing P-03 steadycam with a rokinon 8mm aps-c lens which meant that I could also be relatively close to the subjects and improving audio capture quality a bit. I'm happy overall since it was a small/quick run and gun type of gig.

It was so noisy though that if i brought up the gain any more than 9% roughly it would begin to clip/distort the audio signal.

Might have just been the mic not being able to pick up such a loud dynamic range and distorting though ... in which case wouldnt have mattered which % i set it to. In any case, Setting it to 9% and boosting in resolve a bit gave me good results. Eventually I'll end up getting a pre-amp if i do more in camera audio frequently but for now it's good to know that it works great with some tweaking.

Here are a couple of the clips that i shot (The first clips was before i had set the level down to 9%) :

it could be the case that the sound was just too loud for the mic yes, or perhaps the camera uses negative digital gain which could be lowering the DR too,

this is just an example, but IF the following were true:

100% = +10 db digital gain
50% = 0 digital gain
0% = -10 digital gain

then a low in camera setting would not work effectively to reduce clipping.

to be clear -I have no idea how it works in camera, it might not use digital gain at all -

For proper in camera audio recording, I think someone (maybe me if I have time) should test to find the optimal gain value for the current firmware.

50% is the default level in which there's no digital gain or attenuation.

CaptainHook wrote:50% is the default level in which there's no digital gain or attenuation.

What a good guess!

Good to know, thanks!

CaptainHook wrote:50% is the default level in which there's no digital gain or attenuation.

Good to get an official statement about audio settings. Takes out a lot of guesswork and testing. Thanks.

Does this apply to Mic only or to Line level as well?
Has the zero point always been at 50% or did it chance with the last firmware updates?

Johannes

CaptainHook wrote:50% is the default level in which there's no digital gain or attenuation.

Awesome thank you!

There has been, ever since firmware 1.3, unacceptable basic audio levels. What I mean by this is the following: If you offer a camera with inputs of mic and line level, you should be able to use a powered shotgun mic and get clean audio. DVX100 - clean audio. Sony Z7U - clean audio. Even any Magic Lantern on a Canon Rebel with a mini input - clean audio. BMCC - HISSSSSSSSSSSSSS.

Yes, use a sound person but there are sometimes when you can't.

Other solutions:
Buy an external recording devise. Now I'm spending money and time because BMD won't make it right.

Buy a juicedlink preamp - this is exactly what the issue is. The audio is SO bad, you need a preamp to correct it. Why not just CORRECT THE ISSUE.

I spoke with them today and there is no solution in site because they have no idea that it's an issue.

Only solution - spend more money on something that should be standard.

I spoke with them today and there is no solution in site because they have no idea that it's an issue.

Are you sure you're using balanced TRS cables? If you bring an unbalanced line into a BMCC, you'll get a weak signal. That may be why BMD doesn't see the problem -- they're using balanced leads.

This is the kind of cable you need to patch a shotgun mic directly into the camera.

johnjvogel wrote:There has been, ever since firmware 1.3, unacceptable basic audio levels. What I mean by this is the following: If you offer a camera with inputs of mic and line level, you should be able to use a powered shotgun mic and get clean audio. DVX100 - clean audio. Sony Z7U - clean audio. Even any Magic Lantern on a Canon Rebel with a mini input - clean audio. BMCC - HISSSSSSSSSSSSSS.
=

Recorded in camera using a powered shotgun mic:
http://tommajerski.com/downloads/Audio/ ... pcGain.wav

Sounds pretty clean to me.

The sound got a lot better after about 1.8.