Re: Sound Devices MixPre-6 II (second generation)
Posted: Sun 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.
https://forum.blackmagicdesign.com/
https://forum.blackmagicdesign.com/viewtopic.php?f=2&t=97842
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.
Kim Janson wrote:
Maybe would be good idea for BMD to look into making a audio recorder
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."
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.
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.
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.
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.
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.
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.
Dmitry Shijan wrote: always sounds the same with the same clipping distortion in headphones.
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?
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?
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.
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.
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...
Mattias Murhagen wrote:I googled this and found forums where the headphone amp was discussed and it was all praise and no complaints.
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.
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…
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.
rick.lang wrote:Sound Devices has released version 6.0 for their MixPre recorders.
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.
Dmitry Shijan wrote:By the way i still don't know if headphones distortion noise problem exists in MixPre6II or MixPre10II.
rick.lang wrote: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.
rick.lang wrote:You may have a good point as I’ve only watched the meters. It may not present a sync problem on actual footage.