I am teaching a high school Music unit on technology, and we are studying waveforms and the analogue<->digital conversion. What I would like to do is have the students take a sample of sound/music and resample it at various rates and analyze the effects. With Audacity, it is easy enough to change the sample rate in Hz, but it seems to me that I am stuck with choosing between 16, 24, and 32 bit rates. 8-bit also seems doable by exporting to 8-bit PCM WAV. I would like to go even further, however. So my questions:
Is it possible to quantize lower than 8, or to any rates other than 8, 16, 24, or 32 in Audacity?
Even if I succeeded, is there any reason Audacity or any other music player wouldn’t be able to support other bit rates?
If it is not possible in Audacity, does anyone know what else I might try? ffmpeg or something?
You are mixing up the terms “bit rate”, “bit depth” and “sample rate”.
“Bit Depth” (also called “bit format”) is the numerical format used to represent each sample.
Typically this will be 8, 16, 24 or 32 bit, though others are possible, and there are also variations including “signed integer”, “unsigned integer” and “floating point”.
A higher bit depth provides greater accuracy in representing the amplitude of the waveform, hence it provides greater dynamic range (the range between the maximum signal and the digital noise floor).
If you have 8 bit samples and 1000 samples per second:
The “bit depth” is 8 bit.
The “sample rate” is 1000 Hz ( 1 kHz )
The “bit rate” is 8000 bits per second ( 8 kbps )
steve - Thank you for pointing out my error in expressing depth as rate. I will make sure I don’t make the same mistake when explaining to my students.
Trebor - That is EXACTLY what I wanted. I’m not surprised that Audacity had the feature inside its guts somewhere, but I am happy to find out how to access it!
