Measurement issue with Mac

[Leo11]

Hello everyone.
I have been using REW (latest official) on Mac (Sonoma) for a few months and after several experiments I have come to the conclusion that there may be a little bug in the measuring process.
In summary, if an acoustic reference is not used, the capture ends before the entire sweep is emitted. Sometimes it is even cut at 5kHz.
I tried all possible settings (buffer, dither, play silence, delay, etc.) but there is no way to make it work.
The only way is to use an acoustic reference so it proceeds until it detects it after the sweep.
As equipment I have an Ultralite MK5, with in and out on the same unit.
I make some measurements using the Dirac processor as an out unit and the Ultralite as in, but same behaviour.
It seems strange to me that mine is an isolated case. Also if I use Windows everything works fine.

 

[John Mulcahy]

Sounds like a problem with long replay latency on the mac. The acoustic timing reference removes the latency by waiting for the timing reference to start capture.

 

[Leo11]

Sounds like a problem with long replay latency on the mac. The acoustic timing reference removes the latency by waiting for the timing reference to start capture.

Can I provide you with some additional information / files / logs to find a solution to the problem?
This is a rather limiting problem where it is not possible or necessary to use the acoustic reference (subs, digital loopback, band limited measurements, etc).

 

[John Mulcahy]

Post a screenshot of your REW soundcard preferences.

 

[Leo11]

Here the screenshot.
There is also mic cal file loaded.

And here the captured sweep (10Hz to 22kHz, 256k lenght) without timing ref setted and using Ultralite5 digital loopback channel.

And here the same but with "capture noise floor" and "play dither before sweep" options activated.

The same happens if I use Blackhole loopback audio device.

 

[John Mulcahy]

Make the input and output buffer sizes much smaller, 16k is plenty.

 

[Leo11]

I reduced the buffer to 16k and it seems to work.