As an audacity user with an interest in bioacoustics, I’ve often wanted to view the spectrum of ultrasonic sounds recorded at 384KHz. Currently there is a hard upper limit of 100KHz for the maximum visible frequency in the spectrogram view. I understand that most users will have audio files with a sample rate of 192KHz or less, and that a 100KHz limit is a reasonable default computationally and memory wise, however a warning might be more appropriate than a hard limit.
A cursory look at the source code makes me think that this change would be fairly straightforward. Perhaps when I find the time I’ll attempt those changes and report back how it works.
Thank you for your interest. Your feature request is good and reasonable, but we are in feature freeze mode for 1.3.4 and 1.4.0 now, so we can’t promise it’s doable within current development cycle (there still is time and place for minor changes, however).
So if we can’t have this fixed for you now, we will come back to you the next time. Of course, patches are very welcome anytime
In the mean time, make sure you’ve seen Sonic Visualiser which currently is better suited for working with various ways of sound visualisation. it’s an open source crossplatform application as well
Thanks for the quick reply. I’m keen to contribute in the future, but short on free time at the moment. Also, thanks for the suggestion about Sonic Visualizer -It seems like a very capable tool, but it doesn’t have the streamlined interface that Audacity has. Audacity “just works” in exactly the way I think about things. Thanks for the great software – hope I’ll be able to help in the future.
I finally had a bit of time to look into this:
After downloading the linux source package for version 1.3.4 and setting up the build environment, it was mind numbingly simple to change the upper limit!
I did it by changing lines 137-8 in the SpectrumPrefs.cpp file from 100000 to 200000. I was then able to view the full frequency content of a recording sampled at 288 KHz without any obvious side effects.
I’d be happy to post a patch if it weren’t such a trivial change. Perhaps a better idea would be to replace the absolute limits with a warning message instead. I’ll see if I can manage that.