Apple Impulse Response Utility - Manual (Page 11)

11
Configuring the Sweep Generator
The sweep generator produces a sine wave that sweeps smoothly up from 20 Hz to
20 kHz. The sweep generator parameters set the hardware output, volume, length,
reverb time, and pre-roll of the sine sweep.
To set the hardware output channel for the sine sweep:
m Use the Sweep Channel menu to choose the desired output channel.
To set the output level of the sine sweep:
1 Click inside the Sweep Level field.
2 Do one of the following:
 Drag left (or down) to reduce the volume, or right (or up) to raise the volume.
 Type a numeric value for the sweep level (any value above 0 dB will set the sweep
level at 0 dB.)
Sweep Length
There are three length options for the sine sweep:
 10s: A ten second sine sweep.
 50s: A fifty second sine sweep.
 Off: No sine wave sweep. Choose this setting if you are recording a starter pistol
impulse.
Ideally, you want your sine wave to be short. This avoids artifacts in your recording due
to air motion, rattling of interiors, and other ambient noise—making the 10 second
sine sweep a great choice. Unfortunately, short sweeps may not yield high enough
signal-to-noise ratios in some recording situations. If you find that the results obtained
from recording with a 10 second sweep aren’t all you hoped for, try the 50 second
sweep.
To set the sweep length of the sine sweep:
m Choose the desired sweep length from the Sweep Length menu.