Solid State Logic Soundscape Mixer - Manual (Page 99)

Soundscape Mixpander
Page 99 of 109
High speed SCSI cards
High performance SCSI cards like the Adaptec AHA-2940UW or other Ultra-Wide
SCSI host adapters can block the PCI bus because of the high data rate, which may cause audio
interruptions or clicks. If you experience clicks while using a high performance SCSI card, try
reducing the maximum transfer rate.
Muting of the Mixer due to excessive use of DSP resources
The Motorola 56301 DSP has memory and DSP clock cycle resources that are shared between all
mixer elements and third party DSP plug-ins that are active in the currently loaded mixer. The
Status Bar shows P=xx% and M=xx% for each Soundscape audio card installed in your PC. If either
of these figures exceeds the maximum (100%) for any single DSP then the SSL Soundscape Mixer
will be muted.
However, the DSP processing power figure (P) is calculated from the figures reported by each
individual mixer element or plug-in and as it is very difficult to calculate the “worst case” timing
for each element or plug-in, there may be some inaccuracy in the reported figures. The actual
muting of the Mixer occurs when there is really insufficient time for the DSP to complete the
required processing for the loaded mixer configuration and this may happen with a figure slightly
lower or slightly higher than 100%.
For a given mixer configuration, the “P=100%” DSP power limit can be reached or not depending
on the current Sample Rate. This is because for a higher sample rate, there is less time for
calculations. For instance, if you create a mixer configuration that reaches P=100% at 44.1kHz, then
it will reach P=108.8% at 48kHz. The card will be unable to run this mixer file at 48kHz.
The memory figure (M) is accurately reported by the elements and plug-ins, but there are several
different memory types that can be requested by elements or plug-ins and the figure shown is the
“worst case” usage of any of these memory types. For instance, if a plug-in uses 75% of the X-
memory, but none of the Y or P-memory, then the reported memory figure will be 75% even if the
other memory types are completely unused. It is possible to reach M=100% and yet to be able to
load more mixer elements or plug-ins that do not require the same memory type.
Please note that streaming also uses DSP resources, and this is not reflected in the values displayed
in the Status Bar. Therefore, a mixer configuration that uses 100% of the M or P resources with no
streaming will not function with streaming.