Complete audio newb here. I want to use my Mac to generate and output sound of arbitrary frequency and waveform using a software. Specifically, I am interested in the entire audible spectrum for acoustic studies of musical instruments but also ultrasonic frequencies which are typically used for laboratory applications such as cleaning, cell fractioning, liposome creation (ability to customize waveform is important), emulsification, which, as far as I can tell, are in the 20 to 80 KHz ranger. I have a Mac Pro 5,1 running High Sierra and a 2016 MacBook Pro running Big Sur and would appreciate software recommendations. I understand that output will require amplification and would appreciate any hardware recommendations in this regard. Is the Mac native sound adequate for these purposes or would I need some kind of bridge between the Mac and amplifier? It would be nice if I could pick up and old card somewhere for the CMP 5,1 that would do some of what I need (perhaps audible range?). Thanks for any insights.
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Sound generator for acoustic design and ultrasound emulsifier?
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I think the Mac built-in (analogue) audio output tops out at 96kHz sample rate, and you have to halve that (Nyquist and all that) to get the maximum frequency you can generate - so 48kHz - and that means it can produce a basic sine wave at 48kHz - any other waveform will have higher harmonics that won't be reproduced correctly. Probably, the output will also be filtered to cut out anything above 48k anyway.
The Mac sound system can go up to 192k sample rate digitally and many external USB/Thunderbolt interfaces (even my cheapo Behringer interface) support that, but whether their inputs and outputs can actually pass anything above audible range is questionable - sample rates higher than 48k are really only there to to give you "headroom" so you can squash, stretch and otherwise process audio-frequency data without introducing errors or messing up the higher harmonics... they're not designed to actually work with ultrasound!
Likewise most audio software that supports waveform generation will top out at - well - audio frequencies. I had a quick try and did manage to get VCV Rack to (apparently) max out at a 69kHz sine wave by maxing out the tuning knob and pumping 10 virtual volts into the pitch input - but since I don't have a wet nose and a waggy tail, I can't tell if it worked (not that my monitor speakers would be able to go that high...).
So, I think you're probably looking at specialist/homebrew software to generate ultrasound and - of course - specialist transducers to play and record it - probably lab gear with computer interfaces rather than audio production gear.
Thanks! This points me to a possibly productive path. Perhaps the electronics testing software and hardware area is where I want to look. I originally thought a signal generator's output piped into an amp and output to an appropriate transducer might be the ticket. The journey will be longer than I thought so I'll have to start with baby steps.