I tried the raspbian OS with some moderate overclocking and removing unneeded startup processes. Couldn’t get it under 25 seconds for boot. Kind of a deal breaker (remote start unit could help, but…)
Apparently somebody can start the rpi3 in <3 seconds. I’ll believe it when I try their image myself. Their setup disables USB and networking (maybe audio too who knows) which is a giant pain for configuring my system.
Maybe I’ll try again with an RPi 4 and usb3 nvme. or maybe I’ll just pay hundreds of dollars for a dedicated DSP unit.
In case anyone cares, my main use case is parametric EQ for phon adjusted low bass frequencies. 90dB 20Hz sounds as loud as 70dB 50Hz (give or take) and subwoofers are generally quieter at lower frequencies. Hence, audio processing unit to cut as you go higher than your lowest decently loud frequency.
The lowest cost option for this is about $230USD plus some electrical components (miniDSP 2x4HD). I figure the rpi would cost around $100 including the DAC unit, open source audio software, just need some power source to link the battery to the rpi power cord.
Edit: I don’t want to spam thanks comments for helpful replies, so I’ll just say it here (possibly in advance): thanks!!!