REW Beta Release REW API beta releases

Builds updated today (beta 32) with these changes:

• Added: FSAF measurement method
• Added: Support for importing Flac and MP3 files
• Added: Signal generator has a musical note selector
• Changed: If an error occurs when using the alignment tool via the API the response will be the error message rather than a result with zero delays
• Changed: Increased timeout for blocking API calls to 30 seconds
• Fixed: Using alignment tool through the API might produce zero alignment result
• Fixed: Spectrograms for imported audio data may not have started at t=0
• Fixed: Peak finder copy button did not work
• Fixed: Impulse response import did not use the Analysis preferences default width for the left window
• Fixed: Legend area right click popup could be dismissed by mouse wheel
• Fixed: Null pointer exception when clicking on a colour of the default trace colours in the View preferences
• Fixed: RTA was not correctly processing multi-channel WAV files
• Fixed: RMS+phase and dB+phase averages of measurements whose IRs start at 0 seconds had left window set to zero
• Fixed: Filter panel gain spinner buttons stopped working for negative gains in Macedonian locale
• Fixed: Camilla pipeline format was incorrect
• Fixed: Trace arithmetic 1/A with no gain limiting had incorrect Nyquist level

The big addition is measurement with FSAF, Fast Subband Adaptive Filtering. The FSAF process was developed by by Michael Tsiroulnikov aka Michael Zrull. See Michael Tsiroulnikov (2022). Loudspeakers for AEC: Measurement and Linearization, MATLAB Central File Exchange. FSAF measurement allows total distortion + noise (TD+N) to be measured for any test signal, including clips of music. REW's implementation of FSAF allows measurement with noise signals (white, pink, brown) or a section of a file, which can be WAV, AIFF, Flac or MP3. Help for FSAF measurement is here.

FSAF measurement works very well, but there is an important caveat: the process is very sensitive to clock rate differences and clock rate stability. The best results are obtained when using the same audio interface for both output and input, so there is only one clock source. If the input and output devices are different REW can use timing markers before and after the measurement signal to apply clock rate correction. Even with rate correction applied the results are heavily affected by the stability of the clock sources. USB microphones which rely on the USB clock are not suitable for FSAF measurement as the USB clock is not stable. That means, for example, UMIK-1, UMM-6 and Omnimic are not suitable for FSAF measurements. It is possible to use a USB mic which has an internal clock source, such as UMIK-2.

For discussion of FSAF use this thread.

There are links to API help in the first post of this thread.

The result can be read from here:



It will be a new measurement so the endpoints to get the frequency response or impulse response of a measurement would be used to access the data.

There isn't a way to know what the SPL was for imported measurements. There was a change in beta 32 to the handling of imported data, I'll change that back for IR imports in the next build.

Beta 33 uploaded with this fix:

• Fixed: Some impulse response imports had different SPL offset with beta 32

Bowkey said:

In the latest few versions (30-33), there seem to be some problems when importing sweep recordings.

Click to expand...

Please use the Help menu option to generate a diagnostic file and attach it.

Bowkey said:

Done, I've also included the measurement wav files (including the stimulus) that cause the errors.

Click to expand...

No attachment, perhaps it was too large. You can email it to feedback@roomeqwizard.com

Thanks. For reasons best known to itself the MP3 handler was deciding those measured WAV files were actually MP3. I have uploaded beta 34 to deal with that.

I have added endpoints for RTA file import for the next build, but only one channel can be imported at a time and, since RTA file processing can take much longer than the API command timeout, the import command returns immediately with an OK response and import progress has to be monitored either via subscription or by polling the /import/rta-file/progress endpoint.

Beta 35 uploaded with these changes:

• Added: API endpoints to import files for RTA processing
• Changed: If an error occurs during FSAF processing save the excitation and mic data as wav files
• Fixed: Saving CamillaDSP filters to yaml produced an error

Mike0815 said:

I'm getting some errors with Beta 33:
- Out of memory (heap space)
- Some snakeyaml error while saving camilladsp filters (this worked well in the past)

Click to expand...

The yaml error was an obfuscation bug, fixed in beta 35 which I have just uploaded. The out of memory is occurring when allocating the image data for a spectrogram plot, but I don't see any issues with that even when running REW full screen on a 4k monitor, so the memory must have been used by some action before that. Did you load a very large set of mdat files? REW's heap usage is shown in the bottom left corner of the main window.

Try without the big -Xmx value to see what effect that's having. If you get issues with 3G Xmx send me an example mdat and I'll see if I can reproduce the problem.