• TGL
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  • Registered: 2012-11-20
  • Posts: 59

Topic: Totalmix - SNR -70db?

Hi guys, sorry to bother you again. As previously stated, we got an UFX back from a customer this morning. We have no 2nd unit (and no other RME device)to compare it to.
The totalmix app shows values bouncing around -70db, up to -68 db (peak, w/ -80 RMS) on the analog inputs -w/ nothing connected to them. The mic inputs are lower, around -73 db. Mic gain  Is this considered normal behaviour? I remember using a UCX with far lower values.

Thank you in advance!

2 Reply by MC

  • MC
  • MC
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  • From: Germany/Thailand
  • Registered: 2007-04-06
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Re: Totalmix - SNR -70db?

No, it's not normal. Something broken, maybe in the power supply.

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2012-05-17
  • Posts: 21

Re: Totalmix - SNR -70db?

Hi,
I got the same behavior with my UFX. About -70dB on the analog inputs and -73dB on the mic inputs. Since I only use the outputs which seem to work normal (no noise distortions, etc) I did not take care about that. Could that be an EMC issue? I never got firewire working on my Windows 7 64Bit System.
What would you recommend? Should I send my UFX back?

Regards,
Michael

4 Reply by MC

  • MC
  • MC
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Re: Totalmix - SNR -70db?

It is not normal for a unit that is advertised with 110 dB SNR to show only 70 dB SNR at the line inputs. So send it back and we will fix that.

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2012-05-17
  • Posts: 21

Re: Totalmix - SNR -70db?

Hi,
thanks for the offer. I made some further investigations to make sure and found that the noise level is sample rate dependend:

Samplerate                LineIn         Mic
44.1 or 48kHz            -100dB        -103dB
88.2 or 96kHz            -96dB          -98dB
176.4 or 192kHz         -70dB          -74dB

So to me in a range from 44.1 to 96kHz the values seem to be ok. The behavior on 192kHz seems strange to me. I suspect there is an external source of distortion. I will do some further investigations and write a post, when I figure out.

@TGL: At what samplerate do you see that behavior?

Regards,
Michael

6 Reply by MC

  • MC
  • MC
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Re: Totalmix - SNR -70db?

There IS a manual:

33.7     Noise Level in DS / QS Mode    103

Nobody mentioned the unusual use of 192 kHz before, nor that the value changes according to the sample rate...

Regards
Matthias Carstens
RME

MC's Website

  • TGL
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  • Registered: 2012-11-20
  • Posts: 59

Re: Totalmix - SNR -70db?

For me, its 48 kHz - haven´t tried to change the sample rate yet. I´ll check on monday.

  • Registered: 2012-05-17
  • Posts: 21

Re: Totalmix - SNR -70db?

Hi,
thank you. Now after reading chapter 33.7 that makes sense to me, since I use 192kHz a lot. I am curious what TGL will find out, since it is happenig at 48 kHz.