[sdiy] CPUs, was... Simulating a Moog

[Metrophage]

--- Tim Parkhurst <tparkhurst at siliconbandwidth.com> wrote:
> Even the fastest Macs are only slightly over 1gHz, so how well do
> they work
> if you've got Cubase and a soft synth (or two) running?

The fastest macs these days are dual 2gHZ models, with 64-bit CPUs.
Fast system busses too. The buzzword-like AltiVec math libraries do
speed things considerably, if apps are compiled to benefit from them.
Logic Audio comes to mind (by a factor of 6x-8x faster)

 What's the
> normal
> load of programs for sequencing/recording? And the PC users out
> there: how
> many programs do you normally run simultaneously for
> sequencing/recording?
> NOTE: I am NOT trying to spark another PC vs. Mac debate! I am simply
> curious and am very much a newbie when it comes to computer based
> recording
> & softsynths.

Not too bad! Even on my old mac 8500 (rip) which ran a 132mHZ PPC 604
CPU, I was able to usually mix six to ten tracks of audio in realtime.
Even running VSTi was no problem, so long as it wasn't too crunchy (ie
FFT based).

My G3 runs a way faster system bus. I can run practically any VSTi in
multiple instances with no problems. My 400 mHZ G3 does leave my PII
350 mHZ completely in the dust, my PII is practically useless for real
time audio. Of course these are both late '90s machines.

My problem is that I like very digital sounds and fast, mathematically
intensive patterns. Such as an additive synth with different frequency
bands having various logical transformations performed on them at the
same time, playing real-time editing patterns of 200 bpm polymetrics
with lots of odd meter and divisions. I can't really pull this stuff
off very well on any of my machines. Just as well, because it sounds
like crap anyway! >;]p  But it' what I enjoy.

Using separate machines for sequencing, DSP, and recording DOES help,
but of course it's a pain if your place is not set up for such antics.
I am living at my mother-in-laws house... running two or three
computers in the living room for a few days is not an option! I am in
the process of replacing my old 8500 with a mac 8600, which I have a G3
500 mHz (actually 560 mHZ) CPU to run in. I am going to use this to run
my favorite sequencers, Max and OpenMusic (as well as lots of other
apps which don't run on anything else). I am also trying (slowly) to
fix an Atari Falcon for running Dr T's "KCS Omega 2", probably the most
hardcore sequencing environment ever made, for any system. Then I can
use my G3 for DSP. My wife broke down and bought an AMD 2200+ last week
for her schoolwork, I am guessing that it might be the new
fastest-machine-in-the-house. I can hardly wait to try running Logic on
that!

Ultimately, fastness being measured in mHZ, cycles per second, can be
very deceptive. This tells you how fast cycles are, but not how many
operations per cycle. MIPS - million of instructions per second- is I
think I better guide to gauging performance, but I hear quoted less
often. For instance, my little Analog Devices DSP card runs at abouut
40 mHZ or so, but can crunch audio more steadily than my 350-500 mHZ
CPUs. CPUs are made to do any old process, not to handle audio well. I
doubt if any of our machines could keep up with a 32-bit, 100 mHZ DSP
chip. The chip architecture is just more audio friendly.

I am trying to get into microcontroller and DSP programming, but with a
new baby it is difficult. At least I quit my job, so for a few weeks I
have more time. I intend to make some interface circuits like MIDI to
CV, gate, trigger. And hybrid modules like wavetable oscillators,
quantizers. Might not make much headway for a few months.
CJ


	
		
__________________________________
Do you Yahoo!?
Win a $20,000 Career Makeover at Yahoo! HotJobs  
http://hotjobs.sweepstakes.yahoo.com/careermakeover