AES New York 2015
Workshop W15

Friday, October 30, 6:00 pm — 7:00 pm (Room 1A22)

W15 - Audio Enhancement: How to Improve the Effectiveness of Cross-Channel Filters by Using Time Compression/Expansion to Maintain Signal Alignment

Daniel Rappaport, CACI - Annandale, VA, USA
Eddy B. Brixen, EBB-consult - Smørum, Denmark; DPA Microphones
Gordon Reid, CEDAR Audio Ltd - Cambridge, UK

A common forensic audio enhancement request is to attenuate music or a television/radio broadcast from a recording to unmask underlying speech. Traditional equalization and expansion techniques affect the desired target signal as well as the unwanted noise. When a clean reference recording is available, cross-channel adaptive and lattice filters or dynamic spectral subtraction may be used to cancel out the offending signal. Various tools and filters are available for this type of processing, but they all rely on precise alignment of the reference signal to the recording being enhanced. Even with the aid of auto-alignment tools, word clock drift negatively impacts the effectiveness of the filter. This workshop will present a technique to calculate the linear offset and apply time compression/expansion to the reference track, which increases the effectiveness of the filter.

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EXHIBITION HOURS October 30th   10am - 6pm October 31st   10am - 6pm November 1st   10am - 4pm
REGISTRATION DESK October 28th   3pm - 7pm October 29th   8am - 6pm October 30th   8am - 6pm October 31st   8am - 6pm November 1st   8am - 4pm
TECHNICAL PROGRAM October 29th   9am - 7pm October 30th   9am - 7pm October 31st   9am - 7pm November 1st   9am - 6pm
AES - Audio Engineering Society