[LAU] Sound Chip as a synthesizer on Linux. Thoughts, ideas?

[Tim E. Real]

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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