Sound Devices MixPre-6 II (second generation)

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Dmitry Shijan

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Re: Sound Devices MixPre-6 II (second generation)

PostSun Dec 01, 2019 6:18 pm

Mattias Murhagen wrote:
Dmitry Shijan wrote:I can hear distortion with large headphones if i increase headphones volume to 56 and higher.
I can hear distortion with small plugs headphones if i increase headphones volume to 36 and higher.


The file peaks at 0dBFS True Peak, has an average of -10LKFS and consists mainly of a very low note. That's really a recipe for distortion on many playback systems - unless you turn things down. I would look into the actual schematic of this device to see how the signal flows to make sure you're not missing something.

I don't have this device nor your headphones but judging from what I can see and read here I think your expectations might be off or your testing method.


1. The actual headphones volume is very low when this parasitic noise appears.
2. If i use old MixPre as external headphones preamp and connect it to MixPre-3II line-out i can boost headphones volume really loud without any parasitic noise.
3. If i use old MixPre as external headphones preamp i can hear distortion noise only when headphones volume is boosted VERY high and orange clipping indicator shows headphones clipping.
4. My firewire sound card Echo Audiofire4 with internal headphones peramp produce clean sound without any parasitic noise layers.
5. Maybe it is due analog vs digital headphones amplification?
6. Maybe this is just how ugly digital headphones amplification works in MixPre3II?
7. Maybe it is some internal routing bug that needs to be fixed?
8. Maybe it is defected batch of all early MixPre3IIs? I don't know...
Hope SD tech support answer these questions when they back from holidays.
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Re: Sound Devices MixPre-6 II (second generation)

PostSun Dec 01, 2019 6:20 pm

Well how are the two versions of this device different? Do you have links to manuals?
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Re: Sound Devices MixPre-6 II (second generation)

PostSun Dec 01, 2019 6:32 pm

Under "old MixPre" i mean this legacy mixer. All i know is that it have analog pot. It sounds great as headphone preamp. It sounds slightly better than Echo Audiofire4 internal headphones peamp (which is also very very nice).

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Re: Sound Devices MixPre-6 II (second generation)

PostSun Dec 01, 2019 9:05 pm

Here is video example of that parasitic noise layer that appears starting from headphones volume 58 when use AKG k272HD headphones.
MixPre3II connected as sound card to computer. 40_Hz_-6dB.wav played back from computer.
Headphones connected to MixPre3II headphones out. I put headphones very close to smartphone microphone during recording to record that sound.

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Re: Sound Devices MixPre-6 II (second generation)

PostSun Dec 01, 2019 10:48 pm

Thank you for the video.
I never heard anything like that when playing your 40 and 100Hz clips.
I even produced my own clips with an audio generator and nothing.

I first thought when I heard your clip is that it is related to the power supply.
How do you power it?
Batteries directly connected?
Powerbank USB-C PD?
External USB-C PD power supply?
DC-DC converter?

How is the MP6-II connected to the computer?
USB-C/USB-C or USB?
Have tried switching the cable and/or the USB port on the computer?

On the input stage the mixpre 1st gen did a transformation from analog to digital amplification in the preamp stage. Perhaps their powerful headphone amp stage is suddenly pulling to much power which causes interference from an external switching power source?

Usually switched DC-DC is running at 300k-600kHz and many USB-C is doing 2-4 MHz switch rate so that should not interfere but…
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Re: Sound Devices MixPre-6 II (second generation)

PostSun Dec 01, 2019 11:29 pm

I played back file from computer and also uploaded file to MixPre3II file system and play it back from there. USB powered or battery powered all exact the same. No any changes in noise sound.

I also found that in addition to headphones impedance, parasitic noise appears at different volume depending of different sound frequency:

40_Hz_-6dB.wav start to produce noise starting from headphones volume 58
100_Hz_-6dB.wav start to produce noise starting from headphones volume 62

Also today i had quick attempt to timecode jam MixPre3II with BMMCC. I still not sure if i do things right, but it seems it don't do nothing. I can not see same time indicated on the BMMCC screen. Should it show same time numbers as MixPre3II freerun when jammed?
I switched on timecode input in BMMCC settings, switched to BMMCC audio input to line in, volume set to 100%, switched both devices to same framerate. Have no idea what else i can do. Maybe timecode also somehow related to problem with headphones out? I don't know...

It is odd that Sound Devices have no their forum and we should discuss it in various different places.
By the way, on the MixPre3II box i found sticker "Made in Taiwan" so seems they move manufacture to Asia. On the old "classic" MixPre it was label "Made in USA"
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Re: Sound Devices MixPre-6 II (second generation)

PostSun Dec 01, 2019 11:44 pm

Maybe i need to set timecode Ubits somehow to make it work? This is the only setting that i can't understand yet.
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Re: Sound Devices MixPre-6 II (second generation)

PostMon Dec 02, 2019 2:06 am

To my knowledge the BMMCC audio input can be set to Line och Mic level.
You can also use an audio channel to record and embed a SMTPE compliant LTC into the audio track by selecting Audio Timecode Input.

This does not jam lock the Micro Cinema Camera to the external TC source.
But created a running TC code embedded for process and syncing in post only.

The Micro Cinema can also use the expansion port pin 5 for gen lock multiple cameras during multi angle shots. That’s often used with a central gen lock source that supplies all cameras with gen lock ref signal.


So you should should set your mixpre II to generates TC which you then feed one of the BMMCCs audio input. Left only perhaps?
And the set up the mixpre to do record triggering from HDMI flag and TC from the HDMI output on your external monitors HDMI out. Or if your display do not have HDMI out which carries the trigger signal via a hdmi-splitter between BMMCC and your monitor.

That’s how I understand how do it.

Then a start/stop on the Micro Cinema will trigger a start/stop on the mixpre.
The mixpre own TC gen will record a TC in its multi track was audio as well as an LTC audio track on the BMMCC audio for sync in post.
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Sound Devices MixPre-6 II (second generation)

PostMon Dec 02, 2019 3:18 am

Dmitry Shijan wrote:Maybe i need to set timecode Ubits somehow to make it work? This is the only setting that i can't understand yet.


I just use the Ubits to set CCYYMMDD. I tried to research the purpose of Ubits but couldn’t find anything helpful in the forum places I looked. If course I didn’t look in cinematography textbooks so it may be there.

I may be deluding myself but since Timecode represents HHMMSSFF, I thought it made sense to have the date in the Timecode Ubits.
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Re: Sound Devices MixPre-6 II (second generation)

PostTue Dec 03, 2019 9:35 pm

From BMMCC manual:
"Analog Audio In
The 3.5mm stereo audio connector accepts both microphone and line level audio, selectable in the camera menu. You can also use the analog audio input for embedding timecode onto your video clip by sending an SMPTE compliant LTC timecode in the left audio channel and selecting the timecode option in the camera menu."

So is that means BMMCC can only record embed timecode inside audio file and only when it connected to MixPre3II with cable? No timecode jam sync similar to Pocket4K/6K? That's really odd how could i miss that info before. My audio setup is usually separated from video so i expected some kind of "wireless" timecode synchronization option.

So in addition to unusable headphones-out i also can't jam timecode to the camera. Total disappointment.
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Re: Sound Devices MixPre-6 II (second generation)

PostTue Dec 03, 2019 10:49 pm

I’ve done a write up on this with testing done buts it’s on the other computer.

Basically you can do three routes.

BMMCC doing HDMI TC, Rec trig and locked sync “kind of word clock” out via hdmi to MP on HDMI TC in.
This should work with both mixpre 3/6 and 3/6 II.
Setting on Mixpre: HDMI TC rec trig. Timecode HDMI TC input.

Or let the Mixpre II do LTC from its stereo out to left channel audio in on BMMCC.
Setting on Mixpre: HDMI TC rec trig. Free run TC.
The mixpre 3/6 II can only jam on aux input it seems.

Or external Timecode generator like UltraSync One.
Jam Mixpre on aux TC input from USO LTC out.
Genlock on USO Sync out to Reference input on BMMCC.
USO LTC output to BMMCC.
HDMI rec trig from BMMCC

Depending on monitor, a hdmi splitter might be needed. And the combination BMMCC and first gen mixpre can not jam so then you need the USO do Genlock to camera and LTC to both mixpre and camera.
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Re: Sound Devices MixPre-6 II (second generation)

PostWed Dec 04, 2019 11:38 pm

Some update about headphones parasitic noise problem. I contacted to SD support again and this time they respond that they can hear same headphones-out noise layer on their unit when they playback similar test files. So the problem is definitely there and it is probably something related to gen II models.
And next they tell me that it is OK, because: "You are sending extremely low frequencies to the MixPre-3 II and at the same time, monitoring at relatively high levels via the headphone amp. Essentially, the frequency is clipping (even through the headphone circuit) as your limiters are off. The combination of high levels and extremely low frequency is causing the distorted audio that you are experiencing."

rick.lang, can you please test those sounds https://www.dropbox.com/s/e7idet23874sb ... o.zip?dl=0 to confirm that problem exists or don't exists on your MixPre6 II generation unit headphones-out?
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Re: Sound Devices MixPre-6 II (second generation)

PostThu Dec 05, 2019 12:18 am

I’ll try tomorrow. Busy this evening.
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Re: Sound Devices MixPre-6 II (second generation)

PostFri Dec 06, 2019 5:51 am

Dmitry, the BMMCC can only record the LTC time code signal, it does not jam sync the camera.

Rick, UBits or User Bits in Time Code, go back to ENG cameras, and were used to give a camera a unique TC signature. Depending on the camera you could set the first two to six display bits to a unique Alpha/Numeric ID, like C01 or A02, or a date etc. ENG shooters did not use clap boards, so User Bits gave the camera an ID, and could also be used to set a subject/take ID also.
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Sound Devices MixPre-6 II (second generation)

PostFri Dec 06, 2019 6:09 am

Thanks, Denny. Since I am already using A and B to identify my cameras, I guess there’s no harm in using CCYYMMDD on a shoot.
Last edited by rick.lang on Fri Dec 06, 2019 5:29 pm, edited 1 time in total.
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Re: Sound Devices MixPre-6 II (second generation)

PostFri Dec 06, 2019 8:11 am

Wow, I just noted, close to million views in few months and it is not even a BMD product. I have been viewing a few times too. :)

Screenshot 2019-12-06 at 10.08.58.png
Screenshot 2019-12-06 at 10.08.58.png (38.14 KiB) Viewed 12039 times


Maybe would be good idea for BMD to look into making a audio recorder ;)

Edit, maybe there is something wrong with the counter, it is going up crazy fast, over 1000 in few minutes.
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Re: Sound Devices MixPre-6 II (second generation)

PostFri Dec 06, 2019 9:58 am

Kim Janson wrote:
Maybe would be good idea for BMD to look into making a audio recorder ;)


At least give us some 32-bit float support in Resolve :-)
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Re: Sound Devices MixPre-6 II (second generation)

PostFri Dec 06, 2019 4:32 pm

Dmitry Shijan wrote: they tell me that it is OK, because: "You are sending extremely low frequencies to the MixPre-3 II and at the same time, monitoring at relatively high levels via the headphone amp. Essentially, the frequency is clipping (even through the headphone circuit) as your limiters are off. The combination of high levels and extremely low frequency is causing the distorted audio that you are experiencing."


As expected.

I doubt you'd run into this problem in real-world use that often.
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Re: Sound Devices MixPre-6 II (second generation)

PostFri Dec 06, 2019 5:12 pm

Mattias Murhagen wrote:
Dmitry Shijan wrote: they tell me that it is OK, because: "You are sending extremely low frequencies to the MixPre-3 II and at the same time, monitoring at relatively high levels via the headphone amp. Essentially, the frequency is clipping (even through the headphone circuit) as your limiters are off. The combination of high levels and extremely low frequency is causing the distorted audio that you are experiencing."


As expected.

I doubt you'd run into this problem in real-world use that often.


Yea, sure. It is not a bug it is a feature :) None of other sound cards, mp3 players produce that distortion sound in headphones.
But With MixPre-3 II i can hear that distortion during sound recording and during music playback all the time. This is actually how i find this problem. I just plug MixPre-3 II to computer and start to listen music. Not too loud. All music sounded with slight strange distortion around bass areas. I described it earlier here in details before i got idea to test it with fixed frequency test sounds.
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Re: Sound Devices MixPre-6 II (second generation)

PostFri Dec 06, 2019 10:22 pm

Dmitry,

I think you're going to have to create a more repeatable and comparable test which also takes into account the topology of devices.

It's fair enough to feel that a device underperforms if you do "the same thing" as you do with others and you get distortion. However, since not all devices are the same (which is obvious) it begs the question of whether or not doing it that way is the 'correct' way of going about it.

So when I asked earlier about manuals for the devices it was so that we could compare the signal path. It's entirely possible that you're using the device in a way it's not really supposed to be used, and I'm thinking of the gain structure now, not just hooking it up to a computer. Support said your limiters were off so it's worth asking if the same is true for other devices. And it's worth understanding just how loud a signal is at various points in the signal path since it's possible that other devices modify the gain at some point without you knowing it.
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Re: Sound Devices MixPre-6 II (second generation)

PostSat Dec 07, 2019 1:57 am

Mattias, I just wanted to playback music form it without cracks and distortion. I expect to use it as sound card and as recorder. Test files are only illustrate worst case scenario and allow to hear distortion noise in more uniform way. Source files are not digitally clipped, so device should not produce any distortion during output.
SD tech support keep send me back dumb explanations and force me to believe that about MIxPre3II is clipping headphones because it is so "special":

Thank you for the information. I can easily replicate the issue you are experiencing by loading your setup file on both an original MixPre-3 and a MixPre-3 II. The MixPre-3 headphone amp circuit is not as powerful as the MixPre-3 II circuit. For this reason, I can gain the 40Hz tone and 100Hz tone all the way to 100 and it all sounds fairly clean (as another user mentioned on the forum). However, the MixPre-3 II has a more powerful headphone amp circuit due to the 32-bit float capabilities which includes clipping indicators.

The test files that you sent are incredibly hot as far as gain goes. When we reduce the computer USB output to a better gain range and then open up the headphone circuit all the way on the MixPre-3 II, everything sounds much better - about the same as the original MixPre-3 at the same headphone gain. Proper gain staging is really important for such tests, especially with pure low-frequency, high energy sine wave tones. Please reduce the gain of the recorded files as well as the USB output of your computer so that inbound levels to the MixPre-3 II are reasonable, and I think you will find that everything sounds much better on the headphone monitor.


No it is not "special" it just somehow incorrect digitally increase gain and so clips output due some mistake in hardware or firmware. This problem should be investigated and fixed somehow. This is NOT incredibly hot source file:
Image
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Re: Sound Devices MixPre-6 II (second generation)

PostSat Dec 07, 2019 4:37 am

It is hot. I think you're thinking about things possibly the wrong way and are missing what they're saying.

If you have two devices that convert digital the same way to analog but place a different amplifier in each after conversion the end results will be different. It's absolutely reasonable to adjust gain according to the devices you connect. A powerful amp will output a hotter signal given the same input. You have to adjust to that.

And a steady-state sine wave at -6dBFS is waaaay hotter as far as the headphones are concerned compared to the short duration peak of say a door slam at the same level. It's just not the same thing. Especially not if it's a low frequency signal.

You can think of this as being a non-issue by considering what it's like in a movie theater. Each channel should be calibrated to -20dBFS average pink noise = 85dB SPL. Your dialog might live somewhere around -30LKFS on average, or about 75dB SPL, if memory serves me... This would all mean that a peak spaceship crash would have individual peaks at about 0dBFS which would translate to 105dB SPL per channel, which in turn gets real loud when played back over several channels (left/right/center/LFE).

So now imagine that -6dBFS average tone you created in a theater. It's about 100dB. Sustained. Per channel. It is very loud. Especially for headphones.
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Re: Sound Devices MixPre-6 II (second generation)

PostSat Dec 07, 2019 5:09 am

I try to lower output volume on computer player but without any success. It clips the same in headphones. The only difference is that clipping is starts closer to headphones volume 80 instead of 60.

If i use MixPte3II line-out i have an option to adjust levels on MixPte3II to avoid output clipping, but there is no option to adjust volume levels before MixPte3II headphones amp. It looks like it always send clipped signal to headphones amplifier. As result headphones amplifier starts to clipping distorted noise even at very low headphones volume levels.

By the way, when i overload line-out, the clipping distorted noise sound is very similar to clipping distorted noise sound that i hear in headphones-out.

How is that test signal sound could be hot? It is -6db. It was taken from branded test CD dedicated to test audio equipment. Hot is digital sound that is over 0db. Music is mastered to fit slightly under 0db and and it sounds bright but without any clipping if other things adjusted as they shoulld.
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Re: Sound Devices MixPre-6 II (second generation)

PostSat Dec 07, 2019 5:33 am

:arrow: I repeat again:
In current situation is impossible to listen normal music from computer with MixPte3II headphones-out without some distortion noise in bass. So it is not usable as computer sound card.

You can hear similar distortion noise MixPte3II headphones-out when you monitor loud recordings with reach bass sounds (something like live recording of trumpet).

This problem don't affect recordings itself. It is only related to monitoring sound.

This problem don't exist in MixPte3/6/10 first generation or in any other audio device i ever used in my life.
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Re: Sound Devices MixPre-6 II (second generation)

PostSat Dec 07, 2019 6:36 am

Dmitry Shijan wrote:If i use MixPte3II line-out i have an option to adjust levels on MixPte3II to avoid output clipping, but there is no option to adjust volume levels before MixPte3II headphones amp.


Ok, I watched your videos again (I have no idea why I'm doing this...) There appears to be a menu item under "Outputs" called "St out gain". You left that at zero. I think this is the gain stage the support person told you to lower (and then adjust the headphone amp knob after).

Dmitry Shijan wrote:How is that test signal sound could be hot? It is -6db. It was taken from branded test CD dedicated to test audio equipment. Hot is digital sound that is over 0db. Music is mastered to fit slightly under 0db and and it sounds bright but without any clipping if other things adjusted as they shoulld.


By "hot" I didn't mean "digital clipping", I meant it's a loud signal. Very loud in fact.

If you want a reality check then get yourself a contemporary pop or dance album that is loud and rip a track from it. Leave the output setting at zero change and the computer output to zero. Lower your headphones all the way down to negative infinity (no sound). Play the music. Put your headphones on. Slowly turn up the headphone amp until it's as loud as you think is reasonable.

Does it distort?

Now go to the output section and turn down the output level until it stops distorting. Compensate by turning up the headphone level using the knob until you're back to where it sounds reasonably loud to you.

Does it distort?

If the answer is that it no longer distorts then that's what you need to do for commercial music playback. You can certainly choose to lower the output from your computer and/instead of the one in the device.

PS: In my home studio my Spotify plays back at full level, but my interface software lowers that level by about 20dB. It then goes to my speakers. In other words; in my setup full level from Spotify, which is normally around -14LKFS (i.e. average dBFS) still needs to be lowered so that it's not too loud when I listen in my room. That's because of the amps/speakers. All devices interact and it's a balancing act making things work. When I mix for TV though I reset things so that my mix at -24LKFS sounds just right to my ears. This has to happen because music and movies/tv aren't the same thing. Music is way louder. Your tone louder still.
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Re: Sound Devices MixPre-6 II (second generation)

PostSat Dec 07, 2019 7:22 am

Sound Devices support respond me in exact same way as you. "This is too powerful amp" "try to lower headphones volume" "don't playback single bass sound too long" "what is the frequency response of your other tested sound card?" and so on... Are you crazy people?

"Outputs" -> "St out gain" affect ONLY line-out output. It don't affect headphones output or computer playback output in any way. I explained this earlier.
Headphones volume is currently adjusted way lover than normal real life volume i use during monitoring. I have two options:
1. Too low headphones volume without distortion.
2. Normal or loud headphones volume with distortion.

Please scroll back few posts and see how it starts. I tested it on music files when i found that clipping distortion cracks. Next i have discussion with SD support and send back my unit to reseller and ask for replacement.
New unit came with the exact same problem. So i start to look for more scientific way to find distortion clipping sound and start to use test signal sounds.

Same test signal sounds don't clips on any other sound cards or on first gen MixPre3/6/10. Test signal was designed to test audio equipment. And if audio equipment can't reproduce it - it means audio equipment is broken or adjusted in wrong way.

Currently i am in very contradictory situation. Due headphones output problem i can't get 100% clean monitoring during field recordings and can't use headphones to listen music from computer when MixPre3II connected as sound card.
Same time i like mic preamps and 32bit recording capabilities of this device. I spend a lot of money for device itself, for customs fees and for multiple shippings (i am located far from USA), so sending it back to Adorama again and got simple money refund sounds like waste of $200.
This is just a very odd feeling that i forced myself to use semi-functional device and that Sound Devices support keeps deny this problem and don't provide clear answer if it will be fixed in future or not. I send my first report about this problem more than month ago. At least instead i would like to hear from support something like "ok, we'll see the problem, we work about to fix it, expect firmware update in few months..."
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Re: Sound Devices MixPre-6 II (second generation)

PostSat Dec 07, 2019 8:17 am

+1

If there is distortion when Second generation device is used for the playback but not when first generation device is used for the playback, it seems pretty obvious there is some problem with the second generation device.

I am always suspicious of first generation of devices using completely new technology, and using several ADC on one channel to get 32 bit resolution is completely new way of doing it.

The Idea might not be that new, using second ADC at lower level, but making it fully automatic as these new devices are doing it, is completely new technology.

I am thinking of getting a new recorder, at this time used 'first generation device' i.e. the ones based on the old trusted technology looks like a good option.



Dmitry Shijan wrote:Sound Devices support respond me in exact same way as you. "This is too powerful amp" "try to lower headphones volume" "don't playback single bass sound too long" "what is the frequency response of your other tested sound card?" and so on... Are you crazy people?

Last edited by Kim Janson on Sat Dec 07, 2019 8:58 am, edited 2 times in total.
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Re: Sound Devices MixPre-6 II (second generation)

PostSat Dec 07, 2019 8:27 am

@Dmitry
Could you save you current setting when the problem occur and upload it. Or email it to me in case you dont want it shared.
I'll copy paste me a configuration file to match my mixpre6 and test some more.

Is your Record setting set to Basic or Advanced Mode?
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Re: Sound Devices MixPre-6 II (second generation)

PostSat Dec 07, 2019 8:46 am

Petter, the clipping distortion occurs at any possible settings. It is don't related to bit depth, sample rate, operation mode (Basic, Advanced, Custom), limiters, Low pass filters, timecode or any other settings. I spend a lot of time testing at all possible settings. it is always sounds the same with the same clipping distortion in headphones. I find this clipping distortion problem when i first time connect untouched MixPre to computer as sound card and playback some well known to my ears music during only few minutes.

MixPre support already confirmed that this problem don't exists on MixPre3/6/10 first generation.
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Re: Sound Devices MixPre-6 II (second generation)

PostSat Dec 07, 2019 8:51 am

I see. OK.
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Re: Sound Devices MixPre-6 II (second generation)

PostSat Dec 07, 2019 1:42 pm

Kim Janson wrote:+1

If there is distortion when Second generation device is used for the playback but not when first generation device is used for the playback, it seems pretty obvious there is some problem with the second generation device.


Unless it's the headphones that are distorting because they're driven harder due to a more output from the amp.

Since we aren't in the same room as Dmitry we can't tell because we can't hear the headphone level.

But whatever. I think Dmitry made his mind up that the device is faulty so let's just leave this alone. Nothing's going to change that I think. Hopefully it's not faulty because that would mean a lot of people would have this issue.
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Re: Sound Devices MixPre-6 II (second generation)

PostSat Dec 07, 2019 1:59 pm

Dmitry Shijan wrote:Headphones volume is currently adjusted way lover than normal real life volume i use during monitoring. I have two options:
1. Too low headphones volume without distortion.
2. Normal or loud headphones volume with distortion.


Ok, so let me ask you this then so there's no confusion:

If you leave the output to zero gain change in your computer/music player,
and if the MixPre doesn't do any change either (because it can't change input level),
and if you then increase the headphone volume knob gradually from complete silence until it's the level you want with your headphones on and listening to loud music; what number does that give you on the screen?

And to be clear then if you start lowering the computer output as you are increasing that headphone level amp with the knob;
distortion is still there even when the headphone amp is at "100" and the computer sending signal is now lowered?
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Re: Sound Devices MixPre-6 II (second generation)

PostSat Dec 07, 2019 2:07 pm

Dmitry Shijan wrote: always sounds the same with the same clipping distortion in headphones.


Just so you know: It's difficult for us to hear if what is distorting is your MixPre3 device or if it's mechanical distortion in your headphones. To me it seems that what support is telling you is that you're driving the headphones harder sooner and that's why they are distorting. The situation - if what they say is correct - is similar to you using the older devices, cranking up the volume on your headphones, then replacing the headphones with a different set that is distorting at a far lower level and then you get distortion - not because of the earlier MixPre but because the relationship between output level and headphone sensitivity had now changed.

Come to think of it, another way you can test this is to simply connect your old and new MixPre devices, play back music or your test tone, and record the headphone output and compare the two. If the newer one isn't hotter level or different tonally then the headphones aren't the problem. It might be a bit difficult to match recording levels and I suppose you could just record it analog electrically instead.

Judging from what they say it seems the same headphones should play back louder on the new device than the old - all else being equal.
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Re: Sound Devices MixPre-6 II (second generation)

PostSat Dec 07, 2019 2:36 pm

It sounds more like you have decided there is no problem.

I have opinion either way, I am just suspicious that the new technology very well might have problems, and so this kind of claims make me more suspicious. Denying the problem will not make it go away, just the opposite. So I hope this gets properly handled and soon.


Mattias Murhagen wrote:
Kim Janson wrote:+1

If there is distortion when Second generation device is used for the playback but not when first generation device is used for the playback, it seems pretty obvious there is some problem with the second generation device.


Unless it's the headphones that are distorting because they're driven harder due to a more output from the amp.

Since we aren't in the same room as Dmitry we can't tell because we can't hear the headphone level.

But whatever. I think Dmitry made his mind up that the device is faulty so let's just leave this alone. Nothing's going to change that I think. Hopefully it's not faulty because that would mean a lot of people would have this issue.
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Re: Sound Devices MixPre-6 II (second generation)

PostSat Dec 07, 2019 2:55 pm

Mattias Murhagen wrote:If you leave the output to zero gain change in your computer/music player,
and if the MixPre doesn't do any change either (because it can't change input level),
and if you then increase the headphone volume knob gradually from complete silence until it's the level you want with your headphones on and listening to loud music; what number does that give you on the screen?

I describe it all earlier in details few times and post a video example that illustrates when distortion starts. It depends of headphones resistance. I try 3 different headphones (small and large, consumer and professional) and they all start to distort at slightly different levels. All somewhere between volume 40-60. Different headphones may sound louder or quieter, but they should never produce that digital distortion noise.

Mattias Murhagen wrote:And to be clear then if you start lowering the computer output as you are increasing that headphone level amp with the knob;
distortion is still there even when the headphone amp is at "100" and the computer
sending signal is now lowered?

Yes, distortion is still there even when the headphone amp is at "100" and the computer sending signal is lowered.

The problem is that Sound Devices don't have community and probably all discussion usually goes directly with tech support emails or phone calls. There are also very few forum discussions here and there. By the way when i got replacement unit and find similar problem, i start new support ticket. Old ticket was 631XX and new ticket was 637XX. So it means that during this month Sound Devises registered near 600 support tickets. I don't know is it many or not, but it is just my personal statistics observation...
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Re: Sound Devices MixPre-6 II (second generation)

PostSat Dec 07, 2019 3:37 pm

Dmitry Shijan wrote:
Mattias Murhagen wrote:If you leave the output to zero gain change in your computer/music player,
and if the MixPre doesn't do any change either (because it can't change input level),
and if you then increase the headphone volume knob gradually from complete silence until it's the level you want with your headphones on and listening to loud music; what number does that give you on the screen?

I describe it all earlier in details few times and post a video example that illustrates when distortion starts. It depends of headphones resistance. I try 3 different headphones (small and large, consumer and professional) and they all start to distort at slightly different levels. All somewhere between volume 40-60. Different headphones may sound louder or quieter, but they should never produce that digital distortion noise.


Yes, I remember now. It was about "58" or something like that, right? With 20dB gain or whatever it is you'd reach digital clipping at -84 given that your file is at -6. That's what seems reasonable. So that leaves analog distortion for anything between 58 and 84.

Dmitry Shijan wrote:
Mattias Murhagen wrote:And to be clear then if you start lowering the computer output as you are increasing that headphone level amp with the knob;
distortion is still there even when the headphone amp is at "100" and the computer
sending signal is now lowered?

Yes, distortion is still there even when the headphone amp is at "100" and the computer sending signal is lowered.


And you stopped lowering it at a point where you were still getting the level you wanted on that music, just unfortunately with distortion, right?

Dmitry Shijan wrote:The problem is that Sound Devices don't have community and probably all discussion usually goes directly with tech support emails or phone calls. There are also very few forum discussions here and there. By the way when i got replacement unit and find similar problem, i start new support ticket. Old ticket was 631XX and new ticket was 637XX. So it means that during this month Sound Devises registered near 600 support tickets. I don't know is it many or not, but it is just my personal statistics observation...


I googled this and found forums where the headphone amp was discussed and it was all praise and no complaints.
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Re: Sound Devices MixPre-6 II (second generation)

PostSat Dec 07, 2019 4:09 pm

Mattias Murhagen wrote:I googled this and found forums where the headphone amp was discussed and it was all praise and no complaints.

Can you post a link? Maybe it was discussion about first gen? For example it is a long thread on Taperssection about MixPres 3/6/10 and a lot of posts about gen I and gen II are mixed in same place. Also the product is very new and probably not too many people use it yet. High end sound recorders are way less popular in masses than video cameras.
By the way i still don't know if headphones distortion noise problem exists in MixPre6II or MixPre10II. I can only speak for two units of MixPre3II that i tested personally and for replies of two people from SD tech support team who confirm that they hear same distortion on their MixPre II units when they playback provided test samples. They don't tell me if they use MixPre3II or 6Ii or 10II.
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Re: Sound Devices MixPre-6 II (second generation)

PostSat Dec 07, 2019 4:13 pm

I believe SD have an active Facebook user group.
Check out their FB and see.
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Re: Sound Devices MixPre-6 II (second generation)

PostSat Dec 07, 2019 10:12 pm

Dmitry Shijan wrote:Can you post a link? Maybe it was discussion about first gen? For example it is a long thread on Taperssection about MixPres 3/6/10 and a lot of posts about gen I and gen II are mixed in same place.


You're probably right about that. I probably saw reviews of the wrong device. I missed that.
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Re: Sound Devices MixPre-6 II (second generation)

PostMon Dec 09, 2019 2:29 am

rick.lang wrote:Any opinions about the MixAssist? Considering it but not sure if it makes sense in a narrative film project where I would be using four mics at most…


Did anybody reply to this yet? MixAssist seems to be for unscripted live sound situations (and recordings thereof). A classic example would be multiple people onstage engaging in moderated discussions. In situations like that, MixAssist helps by figuring out who is talking and attenuating the other mics.

In a narrative film, your sound editor in post should be moving each person onto a separate track and should be selecting the best mic for each person, resorting to alternate takes or alternative mics to deal with issues.


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Re: Sound Devices MixPre-6 II (second generation)

PostMon Dec 09, 2019 3:02 am

Thanks, Owen. I agree MixAssist appears most relevant in a Live production.

Re your audio comment:
In my next job in ten days I’m going to work with over 50 tracks in post if all goes well. Interfacing to a soundboard that will send me one channel per mic generally speaking plus four mixed feeds and my own mic for ambience recording. Now that will be new to me, so I see a lot of challenges as I’m not getting any meaningful assistance. The audio will be provided by Audinate’s Dante over Ethernet to a laptop using Reaper as the DAW. All uncharted territory.
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Re: Sound Devices MixPre-6 II (second generation)

PostWed Dec 11, 2019 7:33 pm

Last reply regarding headphones-out distortion problem from Sound Devices support was more optimistic: "Our firmware team is examining this case as well"
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Re: Sound Devices MixPre-6 II (second generation)

PostWed Dec 11, 2019 7:45 pm

Thanks for your perseverance!
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Re: Sound Devices MixPre-6 II (second generation)

PostWed Dec 11, 2019 8:03 pm

Very nice to hear!
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Re: Sound Devices MixPre-6 II (second generation)

PostFri Dec 13, 2019 9:47 pm

rick.lang wrote:In my next job in ten days I’m going to work with over 50 tracks in post if all goes well. Interfacing to a soundboard that will send me one channel per mic generally speaking plus four mixed feeds and my own mic for ambience recording. Now that will be new to me, so I see a lot of challenges as I’m not getting any meaningful assistance. The audio will be provided by Audinate’s Dante over Ethernet to a laptop using Reaper as the DAW. All uncharted territory.


Hey Rick, this sound like a great and terrible engagement. What assistance are you seeking? Maybe you can get a pointer to expert advice here — probably not from me though because I am just beginning to explore the mysteries of audio production.
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Sound Devices MixPre-6 II (second generation)

PostFri Dec 13, 2019 9:58 pm

Thanks, Owen. I’ve been playing with Reaper. Turns out I may only have about 20 channels from the Dante 64x64 but the biggest challenge, after having access to the Dante 64x64 on the Allen+Heath soundboard is getting the sound into Reaper vía the Dante Virtual Soundboard and Dante Controller (both running into a MacBook Pro 13” 2018). I can’t setup much without access to that Dante 64x64 so I can define it as my default audio input source. Would be good to find someone already doing that with the same or similar combination of gear.
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Sound Devices MixPre-6 II (second generation)

PostTue Jan 14, 2020 6:43 pm

Sound Devices has released version 6.0 for their MixPre recorders. This is very good news and hopefully resolved the Timecode jump with frame rates other than 23.976 fps.


https://www.sounddevices.com/download/


New

32-bit float USB audio streaming. Requires Mac OS Catalina (version 10.15+) and an application that supports 32-bit float. Find out if your application of choice supports 32-bit float audio streaming here.
(MixPre II Series only)

Fixed

MixAssist can now be enabled during Playback with ReMix on.
(MixPre-3, MixPre-6, MixPre-10T, MixPre-3 II, MixPre-6 II, MixPre-10 II)

HDMI record triggers no longer create several recordings if the cable was connected while the camera was actively recording.
(MixPre-3, MixPre-6, MixPre-3 II, MixPre-6 II)

Various system enhancements and improvements.


Here are the apps that support 32bit audio streaming:


32-Bit Float Applications

Posted on January 14, 2020
USB Audio Streaming

32-bit float USB Audio. Only supported in MacOS 10.15 (Catalina).

Adobe Audition 2020 Yes, In and Out
Adobe Premiere Pro 2020 Yes, In and Out
Apple FCPX 10.4.8 No

Apple Logic Pro X 10.4.8 No

Audacity 2.02 No

Avid Media Composer 8.6.5 Untested
Boom Recorder 8.7.3 Yes, In and Out

DaVinci Resolve Untested

Izotope RX7 Yes, In only USB Out will clip if signal is > 0dBFS. Workaround: Normalize to 0dBFS.

Protools 2019.12 Yes, In only Waveform displays and USB out appear still clip if signal is > 0dBFS. Workaround: Normalize to 0dBFS.

Reaper 64 v6.01 Yes, In and Out

Steinberg Cubase LE 9.5 Untested
Steinberg Nuendo 10.2 Yes, In only Waveform displays and USB out appear still clip if signal is > 0dBFS.Workaround: Normalize to 0dBFS.In Nuendo’s VST Audio System, select MixPre-II, not MixPre-II (High Precision). Set Nuendo Project to record 32-bit float.


32-bit float WAV Import.


Tested in Windows10 and MacOS 10.14 and higher.

Adobe Audition 2015.2.1 Yes

Adobe Premiere Pro 2015.4 Yes Waveform displays and outputs appear to be 24-bit, Outputs will clip if signal is > 0dBFS

Apple FCPX 10.4.6 Yes Waveform displays and outputs appear to be 24-bit, Outputs will clip if signal is > 0dBFS

Apple Logic Pro X 10.4.6 No

Audacity 2.02 Yes

Avid Media Composer 8.6.5 No

DaVinci Resolve No

Izotope RX7 Yes

Protools 2019.12 Yes Waveform displays and outputs appear to be 24-bit, Outputs will clip if signal is > 0dBFS

Reaper 64 v6.01 Yes

Steinberg Cubase LE 9.5 Yes Waveform displays and outputs appear to be 24-bit, Outputs will clip if signal is > 0dBFS

Steinberg Nuendo 10.2 Yes


So good news for Reaper users (like me). Some limitations with some other popular apps.
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Re: Sound Devices MixPre-6 II (second generation)

PostTue Jan 14, 2020 7:08 pm

rick.lang wrote:Sound Devices has released version 6.0 for their MixPre recorders.



Hey Rick,

Have you had to use the 32-bit feature to deal with what would otherwise be clipping? If so, your impressions?
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Re: Sound Devices MixPre-6 II (second generation)

PostTue Jan 14, 2020 8:57 pm

I’ve used the 32bit audio to record in the MixPre-6 II and processed it in Resolve but I don’t think it went over the limit of 24bit audio. I know Resolve isn’t ready to handle that but in the future I can put it through Reaper to bring levels within 24bit audio for Resolve.

I used Reaper to convert 96KHz from Dante to 48KHz for Resolve in my last theatrical recording in December.
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Re: Sound Devices MixPre-6 II (second generation)

PostWed Jan 15, 2020 2:15 am

Unfortunately headphones-out distortion noise problem is NOT fixed yet in firmware 6.0 :(
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