In and Out from/to the same USB port doesn't work with REW?

[ggHawk]

REW Generator function works fine (sound from speakers). RTA (and SPL Meter) works fine (shows sound when manually making noise into the mic). But simultaneous use of Generator and RTA (or SPL meter) doesn't work - it complains there is no input signal. And "Check Levels" doesn't work in Preferences for the same reason.
Machine is windows 10 with attached USB Presonus AudioBox for both input and output (mic is ECM8000). In the past I've used REW with this same AudioBox (for output), but with a UMIK-1 mic on a different USB port without issues, but I don't have that mic right now. Also, I've used this AudioBox successfully for simultaneous I/O with other apps. Is this a known issue with REW?

 

[John Mulcahy]

No, not a known issue, problem likely lies with the Presonus configuration somewhere. One thing that can cause problems for an interface is if the default formats for the input and output (in the Windows audio properties) have different sample rates.

 

[ggHawk]

Thanks John!. That was it! I'm surprised that the configuration (drop down box) on the REW Preferences page that specifies the sample rate next to the output and input selections didn't override the default settings. That's probably what my Presonus apps did to make it work. I just never looked at the windows defaults for those things since it always just worked.

 

[John Mulcahy]

If you use the WASAPI exclusive option in the Java drivers list (names starting EXCL or ASIO then REW is able to control the interface sample rate, but with the 'normal' Java options the OS makes the decisions and if the rate REW asks for isn't the rate the interface is using the OS will resample. It leaves the card at the default rate, but that becomes tricky when there are two different rates for the same interface

 

[ggHawk]

Thanks again John. Great explanation. I've used WASAPI before, and I thought I tried the ASIO option in the Preferences page driver selection... but maybe I had something else wrong at the time.