Equipment Review FEB/2001
Dolby Headphone
New audio technology licensed by Dolby Labs and soon to appear at the headphone out jacks on most components.
Not a piece of equipment, but a technology that will be made available in a chip for inclusion by manufacturers in the headphone amp circuit of any component providing a headphone jack. Developed originally by Lake DSP of Australia and now licensed by Dolby Labs, the process is somewhat similar to the erstwhile Auri headphone processor or the Lucas processor sold by Sennheiser, but even more effective. The idea of all these approaches is to provide headphone users - whether watching movies on a plane or late at night at home or listening to stereo music - a sonic experience closer to what they would get from a standard 5.1 surround speaker system instead of the rather bizarre effects normally heard via headphones. These effects are usually that of the sound being divided up into three quadrants - one each located right at the left and right ears, and a more amorphous one dead center in the middle of the listener's skull. This can be especially disconcerting when watching a film or TV and the voice of actors - which are placed dead center on the screen - comes from inside your skull.
The Auri and Lucas required the user to select among a series of test tones in order to match the headphone processing more closely to the user's hearing. Even after selecting the tone that place the sound most precisely, both units greatly affected the timbre of music. I for one preferred the more accurate tonally but less accurate spatially sound of plain old stereo on headphones. Dolby Headphone makes no serious alteration of frequency response but does succeed in moving the sounds out of the listener's skull and more into the room. Some persons may find sounds somewhat elevated above their head - here perhaps more precise adjustment with those test tones would have helped - but the effect is still nearly always better than straight stereo on headphones. For Dolby or DTS 5.1 surround soundtracks and discs it is better to selected Downmix on your processor or receiver, or else - even better - select the PCM Stereo option if offered, and then process with Dolby Headphone. One of Lake's demos at shows is to have the listener sit in the sweet spot of a surround speaker setup and then switch between Dolby Headphone and the actual surround speakers. It is impossible to hear the difference, but of course this demo is a custom setup especially created for the room in which the listener sits.
The basic Dolby Headphone technology will be indicated by the new logo as shown above on the test DVD. Their will be no adjustment at the headphone jack on most components, but some higher end components may offer two other enhanced acoustical environments. The standard setting is a rather small and damped virtual room. Option DH2 will be a larger and more "live" room more suitable for music listening. Option DH3 will be a big hall more like a movie theater or concert hall, with much more reverberant field. The test DVD demonstrated all three, and I found Option DH3 highly strange when used on the soundtracks of film scenes taking place outdoors or in small rooms. Option DH2 was nicer than DH1 for most music listening, however.
Singapore and Qantas Airlines have already installed Dolby Headphone on some of their planes' movie systems (while many modern airlines still use 19th-century acoustic ear tubes!!). NEC's latest Japanese notebook PC also has it. Uses of the new technology can be in DVD players, set-top cable boxes, satellite receivers, all types of TVs, VCRs, PVRs, computers, video game consoles, surround decoders, auto sound units, even MP3 portable players. Dolby Headphone makes a great counterpart to the new Dolby Pro Logic II, since both will bring the surround sound experience to more people in more different situations and also make use of the preponderance of sound sources that are plain old vanilla stereo rather than one of the new digital surround sound formats.
- John Sunier
Back to First Equipment Review
Return to the February Home Page
Send Comments to AUDIOPHILE AUDITION!
