[intricatedetail]

It's a shame there are not very many devices working in audio range (sub 100khz). You still have to scout eBay for a device from the 80s-90s and they are still expensive as hell.

[squarefoot]

Many people use quality audio cards plus software to do this.

http://kokkinizita.linuxaudio.org/linuxaudio/

Look for Jaaa, near the end of the page.

Also interesting, although semi-unknown:

https://www.sillanumsoft.org/

[buescher]

Dynamic analyzers are really cool. I'd like one. Too bad they go for silly prices.

Yeah, the niche seems to be filled by software and either sound cards or equivalent USB acquisition hardware.