They can, of course; what made you think otherwise?
As I said earlier, the nice thing about the PWM channels on the Pico is that they accept the same PCM audio format as is used in BBC BASIC for SDL 2.0, so I've simply ported the code from there, with virtually no modifications. As a result SOUND, ENVELOPE, *TEMPO, *STEREO and *VOICE work exactly as they do in BBCSDL.
Back in 1981 you mean? I don't know exactly who it was, it might have been Paul Bond who was in charge of the Machine Operating System (MOS) for Acorn at the time.Who designed the SOUND system as used in BBCBasic ?
RISC OS sound being somewhat different from the BBC Micro has always been a mystery to me. It's true that Acorn's Archimedes didn't have the SN76489 chip, but I expect it could easily have been emulated in software then just as I do now.Then there is the SOUND used in the BBCBasic with the RiscOS ?
Particularly strange is that ARM BBC BASIC has the ENVELOPE statement but it does nothing, even though in the BBC Micro it was entirely implemented in software anyway!
From my (admittedly biased) perspective, Acorn somewhat lost their way once the BBC was no longer actively involved with the specification of the hardware and software of their machines - but of course I would say that!
Certainly when I started to develop BBC BASIC for Windows, 22 years ago now, I was in no doubt that it should emulate the BBC Micro's sound, not RISC OS sound.