Recent content by John Mulcahy

48k is a good starting point.

The ASIO buffer, you mentioned reducing it to 8 samples which is pretty much certain to cause problems. REW's buffers are huge, the 16k min setting is fine.

I don't understand the questions. The loopback provides a timing reference. The timing offset allows additional fixed delays, such as time of flight from source to microphone, to be removed. If you don't care about the timing reference, don't use it.

That doesn't affect clock measurements.

Soundcard calibration is measurement output to measurement input, timing references are not used. No, an output can go to more than one place.

t=0 is offset from the loopback by the offset time.

You can measure the headphone impedance directly. I guess you are sure your splitter is one output channel to two connections and not a stereo output to separate connections. Can you post screenshots of the REW soundcard preferences and the Measure dialog?

High timing errors are not caused by delays. They are usually caused by dropouts on either replay or capture, due to buffers too small or sometimes very long USB leads. For ASIO use the largest buffer setting available. There isn't usually a problem using the WASAPI Exclusive Java drivers...

That's not possible to say with any certainty since you have not posted a measurement of the room alone, only of the room plus the equipment whose behaviour you are measuring. In general RT60 can only meaningfully be measured in a frequency range where the underlying assumption of a diffuse...

There are a lot of very sharp, slowly decaying resonances in that measurement. If those are the things you need to analyse it would be better to use REW's modal analysis features:

Select this:

Java applications are abstracted from the hardware and cannot directly control it. On Windows the WASAPI exclusive and ASIO drivers use 3rd party Java libraries that run native code to enable that access. I don't have an equivalent for macOS.

Thanks, I have fixed it for the next build.

Under macOS the device runs at the rate configured for it in Audio Midi Setup and if REW is asking for something different the OS will resample.

Uncorrelated noise has been on my todo list for a long time, I'll add it in the next build.