Hi everybody,

I tested my computer performance in realtime with the following orc-sco:

-------------------------------------------------------------------

;** orc for realtime test

        sr = 40000  ;** also experiment with other sr and kr rates
        kr = 400
        ksmps = 100
        nchnls = 1      
        instr   1

inum    notnum
icps    cpsmidi
iamp    ampmidi 4000


kmp     linenr  iamp, 0, .05, .03 ;** use relase < 7 secs

a1      oscil   kmp, icps, 1 ;** try also with oscili
        out     a1
        endin

--------------------------------------------------------------------

; sco for realtime test

f1 0 128 10 1 0 1 0 1 0 1  ; audio function

f0 3600 ; allows realtime midi playing for 1 hour
e
---------------------------------------------------------------

I called my realtime version of csound with the following switches:

csound.exe \
-e -O -P99 -p4 -b100 -B100 -odac \
miditest.orc miditest.sco

note that 
the -O flag (non-standard) = suppresses all console text outputs
-e flag  (non-standard) = enables non-standard sr
-p4  (non-standard) = 4 hardware buffers
-b100 and -B100 = length of each buffer so total buffering space is
about 100*4*2=800 samples or 400/40000 = 1/50 of second theoric latency
delay at sr = 40000hz (actually latency delay is a bit grater than 1/50
of sec in win95)
-P99 = enables midi sustain pedal

holding down the sustain pedal and playing notes once a time with my
master-keyboard, I achieved the following realtime performace before
incurring in dropouts:
at sr=40000 and kr=400 I achieved 50 oscili or 90 oscil polyphony
at sr=32000 and kr=320 I achieved 64 oscili or 126 oscil polyphony
at sr=16000 and kr=160 I achieved 144 oscili or 280 oscil polyphony

with a greater buffer length performance are a little better and are
almost equal using standard sr (i.e. 44100 etc.) but latency delay is
bigger and don't allow a good keyboard-playing feeling. 
Note that wavetable length is only of 128 samples so it should be
enterely contained in cache memory.

My computer is a Pentium 133 with 32M of non-EDO ram and 512k of cache.
Could you do this experiment with other PC configurations and other
platforms? I'm especially curious about the realtime performance of
Pentiums with EDO ram and Pentium-Pros with this orc-sco combination.

thanks
-- 
Gabriel Maldonado

mailto:g.maldonado@agora.stm.it
http://www.agora.stm.it/G.Maldonado/home2.htm