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SABINE THE DIGITAL DELAY ADVANTAGE Manual

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THE DIGITAL DELAY ADVANTAGE .....................................................1
- Why Digital Delays? ........................................................................................................................ 2
Loudspeaker Synchronization .....................................................................................2
- How to Synchronize Your Signals .................................................................................................... 2
- Processing (or Group) Delays .......................................................................................................... 2
- Center Cluster Speakers .................................................................................................................. 2
Comb Filter Distortion .................................................................................................3
- Calculating Comb Filter Frequencies ................................................................................................ 4
- Comb Filter Amplitude ..................................................................................................................... 4
- Correcting Comb Filters ................................................................................................................... 4
The Precedence Effect: Aligning the Acoustic Image ..................................................4
THREE APPLICATIONS ........................................................................5
- Application I: Under-The-Balcony Speakers .................................................................................... 5
- Application II: Center Cluster with Front Fills ................................................................................... 6
CALCULATING DELAY TIME USING DISTANCE ................................7
A guide to using Digital Delays
Synchronize loudspeakers
Eliminate comb filter distortion
Align acoustic image
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Summary of Contents for SABINE THE DIGITAL DELAY ADVANTAGE

  • Page 1: Table Of Contents

    A guide to using Digital Delays Synchronize loudspeakers Eliminate comb filter distortion Align acoustic image Contents THE DIGITAL DELAY ADVANTAGE .............1 - Why Digital Delays? ........................2 Loudspeaker Synchronization ..................2 - How to Synchronize Your Signals ....................2 - Processing (or Group) Delays ......................2 - Center Cluster Speakers ........................
  • Page 2: Why Digital Delays

    (or group) delays, and usually range between 0.9 to 5 milliseconds. You will notice that Sabine delays display the processing delay as the smallest possible delay value. You can simply bypass the unit for 0 seconds delay.
  • Page 3: Comb Filter Distortion

    All those in the audience who are closer to the performer than the center cluster will hear the direct sound from the performer before they hear the sound from the loudspeakers. This makes the sound seem to come from the performer, not the loudspeakers. (See the Precedence Effect below.) Comb Filter Distortion Many who took high school science may remember ripple tank experiments where waves are generated from two separate point sources.
  • Page 4: Calculating Comb Filter Frequencies

    Calculating Comb Filter Frequencies The reinforcement and cancellation frequencies depend on the delay time (the time difference between the arrival time of the original signal and the delayed signal). The frequency of the first cancellation occurs at 1/(2 x t) Hz, where t = the delay time in seconds. The cancellations are separated by (1/ t) Hz. Fig. 3 shows how the comb filters change with the delay time.
  • Page 5: Three Applications

    Haas showed that you must increase the loudness of the delayed signal by about 8 to 10 dB (twice the perceived loudness) in order for the acoustic image to move back to the original center position. Increasing the loudness more than this, or increasing the delay somewhat more than 35 milliseconds, makes the delayed signal sound like an echo.
  • Page 6: Application Ii: Center Cluster With Front Fills

    There must be thousands of installations throughout the world like this that "get by" without digital delays. But with the Sabine digital delay, you can improve the intelligibility and add a new quality without ringing up any significant costs. Use the digital delay in this situation to align the visual image with the acoustic image.
  • Page 7: Application Iii: Synchronizing The Signals Of A Far-Throw And Short-Throw Loudspeaker

    It is impossible to remove comb filters with equalization, but a Sabine digital delay eliminates them in short order without affecting the spectral balance for the rest of the audience. Find the axis where the levels from the two speakers are equal. This is where the comb filters are most severe. Carefully adjust the digital delay so that the signal from both speakers arrives at precisely the same time.