I did a fair amount of DSP in the early 90's with standalone boards & PC cards. Mostly machine code (and processing on DOS PCs in C)
After 2 decades in the bush, I find everything has changed and computing power that I only dreamt about is available from the cheapest PC you can buy.
But the knowledge & skills to design eg good digital filters, is still as rare as it was in 1990. What's changed is the wrappers. Today, we have to grapple with EVIL Windoze mixer, a totally undocumented and moving target.
I've successfully designed and optimised digital filters for a couple of fancy microphone projects this Millenium, but someone else had to knit my filters into the Windoze/Mac/Linux applications.
Part of the problem is that my favourite programming environment is still a 1980 DOS C compiler .. the only thing that's survived a couple of HD crashes while I've been in the bush. I've tried to download & install modern compilers like Visual Studio & GCC but 2 decades is a looo.oong time to be away from the sharp end. On both occassions, the cheapo PCs I've bought off eBay died soon after these massive downloads.
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All is not totally sad for this beach bum though.
Circa 1990, I did the theory to measure a speaker and its THD in the theoretically shortest possible time using a log sweep. Professore Angelo Farina re-discovered this some 15 yrs later and its now in all sensible acoustic packages including the latest AP. I'm happy for him to take the credit as he publicised and analysed it in detail.
Using my own version with Audacity and my DOS programmes, I can now do better measurements in the shed I live in than I could in the previous Millenium with anechoic, B&K bla bla.
Alas, this means I need to keep a machine that runs DOS and these will become extinct when working XP machines on eBay are no longer available. XP is the last version of Windoze that will run a sensible DOS graphics window.
None of the new PCs have XP drivers.
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The really useful 'tool' that would make DSP easy for everyone is a well documented hook to replace Windoze mixer so that you can make a PC do what you want soundwise, both for recording & playback ... instead of Windoze 2nd guessing you.
Modern PCs are so powerful that it really doesn't make sense to use a standalone DSP board except for very specialised applications.
If only I can get into the 21st century
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But from what John says, it appears PCs are now passe and I should be looking at moving stuff to tablets & phones instead.
Sigh!