11 Jul
2014
11 Jul
'14
4:43 a.m.
On July 10, 2014 10:59:17 AM Fede wrote:
Hi all,
I have a question on a topic not frequently addressed here, but why not just
asking?
Do any of you run some old sound blaster/adlib/gravis ultrasound card? I
mean the ones with chip synthesizers.
Just started reading a lot about the commodore 64's SID and just found out
lot of my childhood's games actually run the audio on actual synths, which
freaked me out totally.
Probably because there was no way to produce sample driven audio from SID.
Actually, that's not entirely true:
Later in this thread I think Len refers to the General Instrument AY-3-8910.
Ironically both the Commodore SID and the AY-3-8910 *can* produce
sampled audio, the SID in two different ways:
1) Use the SID's 12-bit Pulse Width Modulators to produce PWM audio.
Drawback: Maximum operating frequency is around 3Khz, which gets into
the audio, so you need a low-pass filter down there.
2) Use the SID's or the AY-3-8910's Volume registers to produce sampled audio.
(Set the SID oscillators for 'DC' - the highest f number, or the GI's volume
mode to a 'DC' envelope.)
Drawback - it's only 4-bit audio samples.
It would be nice to have any kind of synth chip running as a hardware
synthesizer on a linux computer, really. In my country, the only PCI card
with an OPL compatible chip is the YMF744b, which seems to be supported by
ALSA. Getting that would mean starting to search for methods to create .o3
(instrument patches) files to be loaded to the card, for which there seems
to be no dedicated native linux software. Maybe through DOSbox?
Anyway. These are still just ideas, because the topic is very vast; there
are lots of different sound chips, and I'm even considering getting a c64
to use it as a sort of assembler csound, if that makes sense.
People familiar to the demoscene are aware of these kind of devices'
powerfulness, but most of that that I've witnessed is tempered scale based
and traditionaly rhythmically structured (and they really rock it that
way), but it would be interesting (to me, anyway) to experiment creating
sound textures and evolving timbres on these sort of hybrid soft-hard
synths. *I might be missing lots of important details on the subject*
As Len mentions later, as far as the actual desired sound produced,
virtually any sound and envelope and filtering you could ever want
can be done 'softly' these days - take a look at the open source
xsynth or zynaddsubfx, they are very 'analog-like'.
However, I think it's great that people today still want to dig in and learn
hardware register level programming, even retro style.
Programming sound chips in those days was a total riot - F.U.N.
There's the question of what you are interfacing these chips to.
Embedded MPU? PIC chip etc?
Or PC driven? For experimenting these days you'll probably need
something like a USB kit like a Velmann kit.
Of course you can stick with the original computer like the C64.
Even interface an IBM to it, so the C64 acts as a command-driven
'sound server'.
F.U.N.
Tim.
So, do you people have any way to enlighten me on this? Any thoughts or
ideas?
Thanks a lot, really.
Fede
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