SoundDevice MixPre-D output gain

@ Chris: I can't say cause most of the other cams were used in a project as B-Roll with no own Audio. About the MixPre-D I can say that it is working. I've used it with several other cameras, like the F55, in the past and it was doing a great job.

@ spacewig: As I've wrote before I'm not an Audio guy. However, the MixPre-D is fine and as Jeroen has the same problems like me it's not the MixPre's fault. Shooting Interviews sound ist massively important so I'd rather buy three Roland R26 a day than having a bad sound quality. Since I want to shoot with the BMCC I'll go two ways till the own BMCC Audio is working properly. About Thomann, the guy who did it is a good friend of mine so never mind possibly wrong service. Despite what you are writing the two PreAmps are working! I've received the JL202 today and combined with the MixPre-D and the BMCC I have great sound results now. So the way it works now is: ME66+K6P to MixPre-D to JuicedLink + BMCC and it is working! To make a point here, this was a test only. I find it to risky to have almost 10 Audio Connections (don't even talk about minijack) for two channels. So what it tells me is that the MixPre-D needs to have a tiny bit more output and everything would be fine...

@Jules: You are right about that. I've heard a lot about different results with different BMCCs while using the same setting and Firmware.

Finally we've found that there is really something wrong with this BMCC too. Ch1 has probably an faulty soldered joint so if you push the plug slightly to da distinctive direction you loose about 15% Audio Gain on Ch1. This doesn't change much about the whole MixPre-D problem since I have the same low input on another BMCC of mine.

Max, thank you for your reply. Your findings relate to another thread I was following on the other forum many months ago. User with MixPre was not satisfied with: SD MixPre (Line out +4dB) to BMCC set to Line input. Levels out of MixPre were too hot to get sufficient levels, noise floor was affecting the audio. They reverted back to firmware v1.2, and the line level audio was fine for their purposes.

While you have now chained another device to reach a suitable level, would you be so kind as to confirm that you have tested: SD MixPre (Line out +4dB) to BMCC set to Mic input, and only test starting from 0% Mic level on the BMCC, moving up incrementally so as to not start out too hot.

I am interested to learn how Mic input, above, compares to your new jL202 that has been added to your audio chain. Perhaps this is a battle between the quality of the pre-amps, yet I wonder if the jL202 is really necessary?

Based on all the threads and discussions I have read over the last 6 months, it would appear that the BMCC needs the audio to reflect closer to the attenuation levels of firmware v1.2. As for other aspects of EQ, etc, I make no such comparison, yet there are documented EQ issues with lower frequencies of firmware v1.3. While dual audio systems are the pro way, it appears to be clear that part of the problem is a firmware related audio issue that can be solved by BMD.

You're welcome Christopher.

Well, I've tried the MixPre Line to BMCC Mic under the latest Firmware and it doesn't work. Even if I'm going down to 1% in the BMCC, the input is way to much so the Audio overrides. Strangly not on the levels but you can hear it pretty bad. Probably with another PreAmp or another Firmware it will work.

I have great results with the the JL202 alone as well with the JL202 and the MixPre combined (bother under BMCC line input). It's really good to hear that the BMCC can give you a great sound quality. However, since I don't wanna go with these two PreAmps combined forever, I think about either switching over to the BMC388 as a stand alone solution or just going with the JL202. The JL202 has no Audio Meters but I can grab them via the bmcc's SDI on my EVF. Do you know if you can 'trust' the audio meters of the bmcc?

Max, perhaps the SD MixPre-D output at +4dB is just too hot for Mic input. I understand the jL and other devices output levels at -10dB. Reviewing the MixPre-D manual, the Stereo Line-level Output (Tape Out) is an unbalanced, stereo, 3.5mm connector and output is aux level at -10dB. Perhaps the tape out is the only way of utilising the BMCC input under the Mic input selection.

As for the Stereo Unbalanced Mic Output (TA3M connector) of the MixPre-D, it is fixed at -36dB.

It would appear that the MixPre-D balanced at +4dB vs juicedLink unbalanced at -10dB output points to the BMCC firmware is not matching balanced Line level from a device, such as the MixPre-D, hence the BMCC firmware should be addressed to match balanced Line level +4dB signal input?

edit: the jL366 does provide balanced output. Output is at -10dB, plus option to increase via a switch?

Max, did you test the MixPre-D 'Tape Out' to BMCC Mic input to compare the audio quality to previous tests you have conducted?

Question to all interested parties: Is it correct to say the MixPre-D XLR balanced Line out (+4dB) into BMCC via audio Line input requires the MixPre-D to be boosted above normal levels together with the BMCC at 100% input level, thus the BMCC firmware likely needs an adjustment to the audio Line input, perhaps similar to firmware v1.2 or other variation?

Hi Chris, no I did not test the Tape Out - just the XLR Mic and Line Outs.
Btw, here is a picture of the SD & JL Bundle working with the BMCC



We did test the MixPre-D earlier on other Camera-Systems and it was fine.
Somehow now the line-out level is around -21db... What the heck

@ Chris: Have you checked the line-out level on your MixPre-D?

Hi Max, thanks for the reply. I have not purchased an SD MixPre-D yet. I have been waiting, and waiting for some resolution with the BMCC firmware. I have distilled that the MixPre-D currently will not be optimised with a BMCC. The one thing about the MixPre-D that I want it for is the audio limiters, they are said to be very good. I have been holding out as long as I can to buy one.

I have also been considering a Zoom H6 as part of a lower cost dual recording system. At this rate, I am considering just the H6, pending a BMCC firmware update. The H6 specs read that the unbalanced stereo 3.5mm Line out is -10dB. For now, I might as well use that to record dual, and feed the stereo Line out into the BMCC with a the appropriately made up Y-cable into the BMCC input via Mic setting. -10dB appears to be in line with the juicedLink signal which I understand is -10dB, perhaps like many other unbalanced pre-amp devices?

My intention was the other way around, run a MixPre-D into the BMCC, then latter add an external recorder for 4 (or more) audio channels, such as the H6. Again, the Mix-Pre-D audio limiters are something I would really like to have, coupled with the quality pre-amp. I'll give the BMCC firmware update a little longer, then acquire one of the aforementioned audio items in the new year.

Btw, those two audio mixers you have now overshadow your camera. My rig is also going to massive when complete. I respectfully suggest you sometime test the Tape Out of the MixPre-D and see what a BMCC Mic input recording sounds like. Is that possible? Thanks.

I do not think putting a line out (-10dB) signal into a " mic" input, it will be too hot. The MixPre does have an unbalanced min out that might work better in camera mic input.

I am going to test this with the Pocket camera. Mill post results.

Denny, yes the Tape Out at -10dB to BMCC Mic input might be the go.

Shame that the Line input on the BMCC is so far off. Is this firmware fixable?

I was testing the Sound Device in a friends Audio Studio and Line Out really just has around -21dBu. So I've sent it in for repair and today the news came that the Sound Device is fine...

Sad but seems that the MixPre-D is not working with the BMCC at all. Meanwhile I've received the Juiced Link BMC 388 and tested it with another BMCC from me - everything is fine.

[/quote]

No, I'm using two Juiced Link preamps, so I can't speak for the MixPre. Sorry.[/quote]


I'm thinking of getting the bmc388... can i ask why you are using 2?

Frank, are you using the MixPreD? Are you having good results with your cables soldered cables like you shows in the diagram? I'm having the same trouble as Maxemanuel has. Really strange. Really low signal level and a very high noise level. It would be great to hear experiences from someone having the MixPreD and the BMCC working like they should!

No, I'm using two Juiced Link preamps, so I can't speak for the MixPre. Sorry.

I'm thinking of getting the bmc388 pre amp... is there a reason you have 2?

I was testing the Sound Device in a friends Audio Studio and Line Out really just has around -21dBu. So I've sent it in for repair and today the news came that the Sound Device is fine...

Sad but seems that the MixPre-D is not working with the BMCC at all. Meanwhile I've received the Juiced Link BMC 388 and tested it with another BMCC from me - everything is fine.

Max, disappointing outcome via the Line (Tape Output) that the SD manual says is -10dB. Since your last post I have purchased a MixPre-D. Disappointed the Line (Tape Output) is not going to solve the problem with the BMCC, pending a firmware update, if one will ever follow that will address balanced Line out from the MixPre-D XLR at +4dB to BMCC Line input. MixPre-D audio limiters were the draw card over the juicedLink. Some of the juicedLink pre-amps may have the option to boost the output level via some of the switches, such as the 366, which makes them more useful with the BMCC in the current state of firmware, from an audio perspective?

Max, alternatively, looking at your first photo, I see XLR cables on the output. Did you actually conduct the test via the Line (Tape Out) with a 3.5mm mini jack cable from the MixPre-D to your friend's mixer?

It may be that to use a MixPre-D with a BMCC, it may require rolling back the BMCC firmware to v1.2.1 and then utilise the MixPre-D balanced Line output at +4dB to BMCC Line input. Reading Chris Hocking's dedicated audio thread (http://forum.blackmagicdesign.com/viewtopic.php?f=2&t=7829) the audio recorded into the BMCC may require correction for DC Offset, if the waveform displays the centre off from 0dB, easily observable when there is silence. Correction via Audition CC is as simple as selecting Favourites > DC Offset from the menu, click ok.

Please BMD, give us a hint that you are or are not looking into addressing this issue?

I'll hook up a MixPre to our BMCC and do some tests sometime over the next couple of days and let you know what I find...

Thanks, Chris.

I'll hook up a MixPre to our BMCC and do some tests sometime over the next couple of days and let you know what I find...

Great, thanks Chris!

I was testing the Sound Device in a friends Audio Studio and Line Out really just has around -21dBu. So I've sent it in for repair and today the news came that the Sound Device is fine.

What do you mean it just has -21dBu? You mean the strength of the signal when you switch on the slate?

I don't have much experience with the MixPre-D as I just recently purchased it, but I've had no problems so far and the audio sounds great. I believe I'm running firmware 1.4, and my settings are as follows:

MixPre XLR Outputs on Line setting
BMCC on Line input at 35%
Balanced XLR to TRS 1/4"

This puts the MixPre-D Tone at -19dbu on the BMCC (confirmed through ultrascope) so, in the field, the limiters on the MixPre kick in just before the BMCC Clips.

Just tried similar setup with my edirol r44. Works perfectly fine on bmcc. My setup: r44's line out to ch1 bmcc set volume to 55% mic. I also have r44's headphone jack out to channel 2, bmcc 55% mic. Monitoring both with edirol headphone jack out has the ability to increase gain levels. Work great except bmcc has very thin sound. Increase bass in post finished the job. Just though I share.

I don't have much experience with the MixPre-D as I just recently purchased it, but I've had no problems so far and the audio sounds great. I believe I'm running firmware 1.4, and my settings are as follows:

MixPre XLR Outputs on Line setting
BMCC on Line input at 35%
Balanced XLR to TRS 1/4"

This puts the MixPre-D Tone at -19dbu on the BMCC (confirmed through ultrascope) so, in the field, the limiters on the MixPre kick in just before the BMCC Clips.

Ashley, when you play back the BMCC files containing the recorded audio in apps such as Premiere, FCP or other audio programs, what are the audio meters reading values of for, say, dialogue?

Does the 1K generated tone playback at -19dB in your NLE or audio editor, subject to the audio limiter threshold you set?

Good to hear you are recording audio that you are satisfied with, we may just need a little more information.

If anyone's interested, I did some tests with the MixPre-D here:

viewtopic.php?f=2&t=17104