Dolby Unveils Soundtrack Loudness Meter; Offers DVD Spectacular Disc
Sound-pressure level (SPL) meters have been around almost since the beginning of sound recording, but almost all of them are instantaneous-response types. The 737 is unique in that it monitors loudness over time and mimics the human ear's non-linear sensitivity to sounds in different parts of the audible frequency spectrum.
Dolby has conducted a number of studies to determine the amount of very loud sound that average theatergoers will tolerate. Movie fans more easily endure intermittent loud noises, such as single gunshots, than continuous loud noises, such as the roar of jet engines. The duration of loud sounds is expressed as an "annoyance factor" in a numerical readout on Dolby's new meter. This factor indicates to technicians whether the sound level should be changed.
The problem of ultraloud soundtracks is particularly acute with movie trailers, which are often mixed at higher levels than films to get the audience's attention. However, this strategy backfires when customers complain, causing projectionists to lower the overall playback level, often to the point at which dialog in the subsequent feature film is too quiet. Dolby president Ioan Allen has written extensively on this problem.
Dolby's efforts to quantify and standardize soundtrack levels have been applauded by the Screen Advertisers World Association and the National Association of Theater Owners. According to NATO president William Kartozian, "This question has been an ongoing problem for exhibitors because it's been a problem for our customers . . . We're happy that all segments of the industry---led by Dolby---are addressing this issue." The Trailer Audio Standards Agreement was developed last year by a consortium of theater owners, movie studios, and sound engineers. The 737 Soundtrack Loudness Meter is an outgrowth of that agreement.
A Dolby product of special interest to home-theater fans with DVD players is DVD Spectacular, a 5.1-channel recording that includes orchestral and piano music as well as audio and video test signals for calibrating home-theater systems. The disc also has four Dolby film trailers and recordings of Tchaikovsky's 1812 Overture in both 5.1 and traditional stereo for comparison.
DVD Spectacular costs $25 plus $5 handling in both the US and Canada. The distributor is Proxy, which can be reached at (800) 983-6529. Ask for product line number 22800. Payment is by credit card only. Dolby Labs emphasizes that the disc is available only through Proxy; all orders sent to Dolby will be returned.