Recording Audio into Impulse Response Utility

Once you have made hardware assignments and configured the monitor and sine sweep parameters, it’s time to start recording audio tracks.

If you are using the sweep generator, you will hear the sine wave sweep up through its frequency range. Impulse Response Utility will record the result onto the selected audio track(s).

If you have set the sweep generator to Off, click Record, and shoot your starter pistol. Impulse Response Utility will record the resulting impulse response onto the selected track.

To select an audio track
Do one of the following:
  • Click in a track lane.

  • Use the Up and Down Arrow keys to navigate through the track list.

To record in Impulse Response Utility
  1. Select an audio track in the Inputs/Track section.

  2. Configure the audio track for recording.

  3. Repeat this step for each track required by the chosen format.

  4. Click the Sweep/Record button to begin recording.

Configuring Audio Tracks for Recording

The Inputs/Track section is automatically filled with the number of tracks required for the impulse response recording, based on your selections in the New Impulse Response Project dialog. Every track lane in the Inputs/Track section has a number of parameters. Some are automatically configured by Impulse Response Utility; others you will need to set before recording.

Figure. Track (lane) parameters.
Track Parameters
  • Speaker Position pop-up menu: Selects the speaker position label for the selected track. Both Impulse Response Utility and Space Designer use these labels to identify, and process, the audio files that comprise a multi-channel stereo or surround impulse response. Impulse Response Utility automatically sets the speaker position label for each track, but you can change these labels to any other position (available in the current impulse response format), if desired.
  • Mic Position pop-up menu: Selects the mic position label for the selected track. Both Impulse Response Utility and Space Designer use these labels to identify, and process, the audio files that comprise a multi-channel stereo or surround impulse response. Impulse Response Utility automatically sets the mic position label for each track, but you can change these labels to any other position (available in the current impulse response format), if desired.
  • Input pop-up menu: Sets the physical input for each track. Be sure to select the correct input before recording.
  • S[olo] button: Click to engage or disengage solo mode for the selected track. When the Solo button is engaged (yellow), the input signal is routed to the monitor section, and the input level is displayed in the VU meter (see “VU meter” below). Only one track can be soloed at a time.
  • R[ecord-Enable] button: Places the selected track into record-ready mode. The R button turns red when engaged. Clicking this button also activates the Solo button for the selected track, allowing you to monitor the input signal before recording. You can record-enable several tracks at once, for multi-channel recording. When you click Sweep/Record, a recording will be made on all record-enabled tracks.
  • L[ock] button: As soon as one track is locked, the sweep generator parameters are also locked. This ensures that any subsequent recordings will use identical sweep settings. This is necessary, as every track must use an identical sine sweep—in order to produce a phase coherent, accurate, multi-channel impulse response.
  • Peak field: Displays the peak level value in dB. If the level ever exceeds 0 dB, the peak value is held until cleared. Clicking the Peak column header resets the Peak readout for all tracks.
  • Level: Displays input meters for each track. These level meters always show the current level of the physical inputs.
VU Meter

Measures either the signal level present at the (soloed) track input, or the sweep generator output. During playback of recorded audio, the VU meter displays the level of the selected track. A status message below the VU meter shows its current operating mode. The VU meter scale ranges from 0% to 100%, with 100% equalling 0 dB.

Figure. VU Meter.

Making a Recording

Once you have configured and record-enabled the desired tracks, click the Sweep/Record button. If you are using the sweep generator, the button shows “Sweep.” If you are not using the sweep generator (Sweep Length parameter is set to Off) the button shows “Record.”

  • Clicking Sweep automatically starts the recording process and generates the sine sweep. The VU meter is automatically switched to display the sweep generator output.

  • Clicking Record automatically begins the recording process. Shoot your starter pistol and Impulse Response Utility will record the audio.

Recording will continue until the entire sine sweep (if the sweep generator is being used) and Reverb Length time has elapsed. The recording automatically ends. You can abort the recording process by clicking the Sweep/Record button.

Note: The Sweep/Record button is disabled if no track is record-enabled.

Automatic Saving of Projects

Impulse Response Utility records into your computer’s RAM, not to your hard disk. This means that nothing you have recorded is saved, until you save your project.

For your convenience, Impulse Response Utility automatically saves your project to disk after every recording.

If you haven’t saved your project, the Save dialog is opened, allowing you to name your project, and choose a hard disk location. If you have already saved your project, the save process happens automatically. See Saving, Opening, and Reverting to Saved Projects for more information.