Digital Synths

David Halliday (Volt Computer) a-davidh at microsoft.com
Thu Jun 19 17:43:12 CEST 1997


There is a dated but excellent intro:  Hal Chamberlain's Musical
Applications of Microprocessors which goes into great detail about the
"classical" digital synth you are talking about including schematics and
code stubs.

What might be of more interest is the new crop of Digital Signal
Processor chips ( DSP ) from companies like Texas Instruments and Analog
Devices.  There is rumor of an Analog Devices DSP with decent A/D and
D/A all on a PCI card for under $200 - I am familiar with their big
SHaRC development kits but these cost upwards of $1K-buck and are out of
my range...  Anyway, one of these PCI cards, a decent PC clone and a
copy of CSound with one of the front end processors would be an
excellent place to start experimenting with digital synthesis.

MODERATOR ALERT:  RETURNING TO TOPIC - RETURNING TO TOPIC - 

My interest though is Analog synthesis - there is something wonderful
about the sound.  I think that a marriage of Analog tone generation and
signal processing with digital control and sequencing systems will offer
the best of both worlds.


In terms if I/O - going from the PC to the synthesizer, there is no real
need to go for a proprietary connection.  There is a high-speed digital
serial connection called FireWire which was initially developed by Apple
but has been released into commercial use and is now available on many
new motherboards.  The speed of this is such that it can support
streaming video, several channels of digital audio, hard disk drives,
etc...  There are cheap support chips available so incorporating this
into a new design is not a difficult matter.


As for schematics, it is pretty much roll your own for now.  There is a
wonderful body of traditional analog schematics archived at various
sites and the technologies to interface to them are well known, it is
just a matter of putting the two of them together with some software
"glue"


> -----Original Message-----
> From:	Matthew Porth [SMTP:mporth at videologic.com]
> Sent:	Thursday, June 19, 1997 8:33 AM
> To:	synth-diy at horus.sara.nl
> Subject:	Digital Synths
> 
> 
>      
>       Hi all,
>      
>      
>         After reading the recent postings about PIC / Stamp 
>      microcontrollers I was wondering if there is any schemtacis and
> info 
>      for digital synths based around ADC / DAC's and CPU's. These
> digital 
>      systems interest me because I am a software engineer and have
> been 
>      coding for a very long time...
>      
>         I am not really interested in Stamp / 8051 designs as I think
> they 
>      are a little long in the tooth now.
>      
>         I am looking to use at least 1Mbyte of SRAM, at least 3 serial
> 
>      ports (MIDI In, Midi Out+Thru, Hi Speed serial IO (115200 Baud)
> for a 
>      PC link), ADC/DAC via some kind of DMA device or more probably a
> FIFO, 
>      a programmable clock device (5Khz up to 44.1Khz) and the SA110
> CPU 
>      (StrongARM running at 233Mhz).
>      
>         Of course one could always use an 8 bit parallel port
> interface 
>      which would allow a stupidly fast PC link (1->6 MBytes Per
> Second).
>      
>         What it really boils down to I am a software engineer not a 
>      hardware designer. Are there any schematics of digital CPU
> controlled 
>      synths on the net?? Are there any mail lists / news groups that
> deal 
>      with the building of simple computers. I have yet to find
> anything!
>      
>         TIA
>      
>                 Matthew.



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