10.6

288Logic Pro Effects
When you select a half sample rate, the impulse response becomes twice as long.
The highest frequency that can be reverberated is halved. This results in a behavior
that is much like doubling every dimension of a virtual room—multiplying the volume
of a room by eight. The Low (and Lo-Fi) setting can also be used for interesting
tempo, pitch, and retro digital effects. Another benefit of reducing the sample
rate is that processing requirements drop significantly, making the lower quality
settings useful for large, open spaces.
This behavior also applies when you choose Lo-Fi, but the sample rate is divided by
four and the impulse response is multiplied in length four times.
• Medium: Space Designer uses the current project sample rate. The sample rate of
a loaded impulse response is automatically converted to match the current project
sample rate, if necessary. For example, this allows you to load a 44.1 kHz impulse
response into a project running at 96 kHz, and vice versa.
• High: Space Designer uses the highest possible sample rate.
• To retain the original length of the impulse response when the sample rate is changed:
Adjust the Size knob value. Using this parameter with your Quality pop-up menu choice
can lead to interesting results.
If you’re running Space Designer in a project that uses a higher sample rate than the
impulse response, you may also want to reduce the impulse response sample rate.
Adjust the Size knob value to reduce CPU processing time without compromising
reverb quality.
Tip: You can make similar adjustments while running in Synthesized IR mode.
Most typical reverb sounds don’t contain an excessive amount of high frequency
content. If your project is running at 96 kHz, for example, you would need to use
lowpass filtering to obtain the mellow frequency response characteristics of many
reverb sounds. A better approach would be to first reduce the high frequencies by
choosing a lower rate from the Quality pop-up menu, followed by using the lowpass
filter, thus conserving significant CPU resources. It is also worth noting that longer
impulse responses (sampled or synthesized) place a higher strain on the CPU.
Set impulse response lengths
• In Logic Pro, rotate the Length knob to set the length of the impulse response—sampled
or synthesized.
The Length knob setting changes the decay value, depending on the current Size knob
value. To clarify, a Length value of 100% and a Size value of 100% result in a decay that
is the full length of the loaded impulse response.
All envelopes are automatically calculated as a percentage of the overall length.
Changes to the Length or Size parameter values result in envelope curves stretching
or shrinking to fit the new impulse response length.