Re2: Digital Synths

David Halliday (Volt Computer) a-davidh at microsoft.com
Thu Jun 19 19:48:17 CEST 1997


Hi Matthew

I just spent about ten minutes at the ARM site and although it looks
really tasty, I have some problems with it...

First of all, you say that the cost of components for this system would
be about $150

There is a price list on the ARM web site and the cable to go from their
development board to a printer port is $135!
Their cheapest development board ( hardware only - this price is without
any software ) is $486 for a 512K system and their Software Development
Kit is $3,500...  Their top-end hardware development board is $4,400

There are a number of operating systems supported by this chip - most of
them are for industrial real-time systems. OS-9 is fairly widespread.
Since these OS's are not sold in the tens of millions like MAC, Solaris,
DOS and Windows, their price tends to be in the thousands of dollars -
this is not a problem when they are being used in industrial situations,
controlling machines which cost several tens of K-bucks, but when one is
trying to kit-build something from scratch, this is out of line - way
way out of line...

The reason I was suggesting using a PC is that they are everywhere and
that they are cheap and that you can build a nice system for music with
one and still be able to use the PC for other tasks - writing more
e-mail, doing your books, etc...  Spending so much money on a system
which can only do one thing, which you have to write *everything*
yourself, which has ZERO support for any of the development tools (
either not there or priced out of reach ), doesn't seem to me to be a
real world use of ones time or resources.

The ARM chip may be academically superior to the Intel or the Motorola
chips but until they reach real-world parity in terms of dev tools,
support, price, availability...  I see no reason to even consider them.




As for the quality of sample / playback of PC cards - true, the
Soundblaster cards are pretty poor.  They actually do an amazing job
considering the amount of digital noise and RF careening around the
inside of the box.  There are some other cards available which, for a
couple hundred bucks, do an amazingly good job.  

I would suspect that the Motorola board I was talking about would be
pretty good - not audiophile but better than SB.  You have to consider
that this board is being made by Motorola with the express interest in
getting people to use their DSP chips in a PC audio environment.  It is
in their best interests to make this puppy sound as good as possible.



> -----Original Message-----
> From:	Matthew Porth [SMTP:mporth at videologic.com]
> Sent:	Thursday, June 19, 1997 10:52 AM
> To:	synth-diy at horus.sara.nl
> Subject:	Re2: Digital Synths
> 
> 
>      
>      Hello again,
>      
>         I suggest you have a look at the StrongARM system (lots of
> info on 
>      the digital site and at www.armltd.co.uk). These systems have a
> lot of 
>      really nice features that make them scarely efficient performers.
>      
>         I am not looking at x'miting digital data to the PC (although
> you 
>      have just given me a good idea!). It may be that I just use 2
> MIDI 
>      setups on the DigitalSynth card.
>      
>         The advantage of this other using software synths on my PC is
>      
>         - don't have to put up with the shit sample / playback quality
> of 
>      PC cards
>         - can do MIDI and DAC stuff together RELIABLy
>         - can build effects that can be MIDI controllable (e.g.
> flanging/ 
>      delay synced to a multiple of the current music tempo)
>         - don't have to have 2 PC's (thats like BIG SPACE)
>         - cost of components is about $150, not $2500 ;)
>      
>            Matthew.
>      
>      PS - digital synths are allowed here, Aren't they???
>      
>      _____________________________oOo_______________________________
>      
>      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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