User manual APPLE IMPULSE RESPONSE UTILITY

[. . . ] Impulse Response Utility User Manual Apple Inc. © 2007 Apple Inc. Under the copyright laws, this manual may not be copied, in whole or in part, without the written consent of Apple. Your rights to the software are governed by the accompanying software licence agreement. Use of the "keyboard" Apple logo (Option-Shift-K) for commercial purposes without the prior written consent of Apple may constitute trademark infringement and unfair competition in violation of federal and state laws. [. . . ] Note: While it is possible to deconvolve each audio track once recorded, there's really no point in working this way; it's far more efficient to wait until all tracks are recorded, and then deconvolve them. 16 Editing and Auditioning Your Impulse Response Once you have recorded (or deconvolved your recorded tracks into) impulse responses, you can use the Editing area to do some "touching up" of your impulse response. You can use the Audition IR window to hear how your impulse response sounds when applied to a test audio file. Editing Your Impulse Response When you have finished recording your audio tracks, you may feel that they have superfluous silence at the beginning or end of the file, don't fade out early enough, and so on. To address these minor issues, Impulse Response Utility allows you to cut, crop, and fade your audio files in the Editing area. Your audio file will automatically appear in the Editing area. You can choose from three different display modes in the Editing area: Â Waveform: Shows the recorded audio as a standard waveform. The vertical axis displays the frequencies, which are color coded by dB range. The color legend in the upper right corner of the Editing area indicates the color schema. These display modes allow you to effectively analyze your waveforms, making it easy to identify material you need to cut or crop, or that requires a fade. The Spectrogram mode, in particular--which simultaneously shows frequency, level, and time--allows for very detailed analysis of your audio. 17 Transport Buttons The Editing area contains two transport buttons: Â Play: Starts or stops playback of the selected audio track. When Cycle mode is engaged (the button is darkened), playback of the selected track repeats continuously. Editing Functions Impulse Response Utility offers three editing functions, accomplished via the two editing buttons at the top left of the Editing window: Cut, Crop, and Fade. All edit functions are accomplished by using the same steps: 1 Click-drag over a portion of the audio in the Editing area. Â Crop: If you make a selection that doesn't extend to either the beginning or end of the audio, the left edit button activates the Crop function. Clicking this button will remove the audio to the right and left of your selection, without touching the selected audio. Â Cut: If you make a selection that extends to either the very beginning or very end of the audio, the left edit button activates the Cut function. Clicking this button will remove the selected audio, without touching the unselected audio. Â Fade: If you make a selection that includes either the very beginning or end of the audio, you can select the Fade function. Clicking this button creates a gradual fade over the length of the selection area. Note: In order to maintain phase coherency between all tracks of your impulse response, edits are performed across all tracks equally. To ensure that your impulse response cannot include tracks that are not edited equally, you are prevented from recording further tracks once an edit has been made. 18 Auditioning Your Impulse Response To really know how your impulse response will sound when used in Space Designer, you need to be able to listen to it in context. Impulse Response Utility includes an Audition window for just this purpose; where the loaded impulse response can convolve test audio files. The Audition window is divided into three sections: the Impulse Response area, the Monitor area, and the Audio Test Files area. Impulse Response Utility allows up to five audio files to be loaded/used as sources when auditioning your impulse response. The Audition window offers the following parameters: Â Enable checkbox: Enables or disables individual impulse response recordings. [. . . ] Step 2: Creating a new project The next step is to open Impulse Response Utility and create a new five channel impulse response project. The New Impulse Response Project dialog informs you that this format requires five speaker positions and five mic positions. When you exit the dialog, twenty-five audio tracks will appear in the Inputs/Tracks section--one for each speaker position, from every microphone position. Step 3: Configuring Impulse Response Utility parameters Position your microphone towards the speaker you want to record (the left front speaker, for example). [. . . ]