A few settings are available that affect the CPU usage of Stereo Tool.
The easiest way to reduce the CPU load is by adjusting the Quality setting (see the
bottom of this page). That probably suffices when you're just listening to music.
If you're broadcasting and you're using Loudness to reach extremely loud volume
levels, or if just using Quality doesn't suffice to reduce the CPU load enough,
go through all the settings on this page.
Screen refresh speed
The first step to limit the CPU usage is to lower the screen refresh speed.
Note that this only affects the CPU usage if the window is visible, not if
it is iconified. The effect of this is small, but the audio quality is not
affected.
Turn AZIMUTH correction off
If you're using no stereo widening or Stereo Boost (and not Stereo Image Processing),
turning AZIMUTH correction off will reduce the CPU load. This has no effect on the sound,
provided that your input signal does not suffer from AZIMUTH problems (time shifts
between left and right channel, which mainly occurs on tape recordings, but some
CD's with old music also suffer from it.)
If you're using modern good quality CD's, you can safely turn AZIMUTH correction off.
Explanation: Stereo Boost is combined with the Multiband compression, and uses
little extra CPU power if multiband compression was already enabled. AZIMUTH
correction and Stereo Image Processing are combined into another filter, which
can be skipped completely if both are turned off.
Multiband compressor "HQ" setting
Turn this off to reduce the CPU load a bit. This may introduce some distortion
on deep bass sounds, especially when Quality is set to Low. At Normal or High quality,
the effect on the sound quality is very limited.
Combining Limiting and Loudness
If you have both Loudness and Limiting enabled, you can reduce the CPU load
a lot by combining them. This may slightly reduce the output volume.
In the Limiting & Loudness window, enable "Do not preserve loudness ...".
Note: When Loudness is set to 1.00 (off), this may have very big effects on the
output volume and cause severe pumping - so only do this when Loudness is used.
Quality
Finally, it is possible to change the overall sound quality.
The difference in sound quality between Hi and Mid is very small, while the difference
in CPU load between the two is large.
The difference in sound quality between Lo and Mid is a lot bigger, and the difference
in CPU load is smaller. Especially when Loudness is used, use Lo only as a last resort.
The differences mainly affect very deep bass sounds. When using Loudness, at quality
Mid the output volume is a bit lower, and at quality Lo it's a lot lower.
Differences are mostly audiable with very simple one-tone sounds, eg. classical
music will get the biggest gain in sound quality when the quality is set to
high. For "wilder" types of music and other recordings, the difference is
probably inaudiable.
