• Registered: 2011-12-16
  • Posts: 59

Topic: External sync/lock on HDSPe AIO + +

Mac Pro 8-core 2010, OSX Lion.

Could someone explain what's going on, and if this is the correct behavior....

I use an external converter (Benchmark ADC-1) and want to use its clock as master. The AIO is set to clock mode "Autosync". All incoming sample rates are registered correctly by the AIO in the "Preferred Sync Ref / Input Status" field.

However, the "System Clock" field behaves strange....
Going from 44.1 to 48 on the Benchmark - the "System Clock" field also changes from 44.1 to 48, and the Input Status shows "Sync" besides the digital input field. BUT, going to 88.2 - the system clock goes back to 44.1, and going to 96 it goes to 48. Same for 176.4 and 192 - the system clock just goes back and forth between 44.1 and 48, and the Input Status now shows "Lock" instead of "Sync".

If I manually change the sample rate to e.g. 96 when this is what the external converter is set to - the AIO will go back and forth between 96 and 88.2 instead. IOW, it seems the AIO will only sync to 1 "multiplier"?

Is the AIO performing some sort of sample rate conversion when it displays "Lock" instead of "Sync"?

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Also...when playing back audio files (Quicktime and iTunes) the AIO doesn't follow sample rates....meaning, the AIO stays at whatever sample rate it's set to (AIO is master). Playing back a 44.1 file when the AIO is at 192 sounds....eh, interesting....

  • Registered: 2011-12-16
  • Posts: 59

Re: External sync/lock on HDSPe AIO + +

Ok, operating system does not make a difference. Checked on a Windows 7 partition too.

Can anyone from RME please confirm? The input status shows the correct incoming sample rate, but the "system clock" only moves back and forth between the two rates of the "same multiplier" it was last set to (eg 44.1 and 48, or 88.2 and 96 etc). Only when incoming rate and system clock corresponds does the card show "sync", else it shows "lock".

What's happening? Do I have to manually change between multipliers? Does the card halve/double/triple the incoming sample rate when input status and system clock fields don't correspond?

  • From: Germany
  • Registered: 2007-04-10
  • Posts: 9,603

Re: External sync/lock on HDSPe AIO + +

Runepune wrote:

However, the "System Clock" field behaves strange....
Going from 44.1 to 48 on the Benchmark - the "System Clock" field also changes from 44.1 to 48, and the Input Status shows "Sync" besides the digital input field. BUT, going to 88.2 - the system clock goes back to 44.1, and going to 96 it goes to 48. Same for 176.4 and 192 - the system clock just goes back and forth between 44.1 and 48, and the Input Status now shows "Lock" instead of "Sync".

The behaviour is normal. The sample rate range will change e.g. as soon as you initiate playback or recording in your audio software.


Is the AIO performing some sort of sample rate conversion when it displays "Lock" instead of "Sync"?

No.

As for iTunes, the system sholuld resample. Is the driver up to date?


Regards
Daniel Fuchs
RME

Regards
Daniel Fuchs
RME

RME Support's Website