Sound for home theater – the kind of sound that engenders what’s termed, “the immersion experience” – is not dependent on loudspeakers alone. Nor on amplifiers, a DVD player, cables, or any other gear.

What makes home theater sound like a movie theater is the loudspeakers and the particular room they occupy. The immersive feel of home theater, where the surround sound envelops you in the total experience, comes from a perfect balance between image and sound. Anything that throws this balance off, works against the experience. The space needs to make psychoacoustic sense to the brain; your visual perception of the room has to balance with your auditory perception. If it doesn’t, your brain gets very upset, quite literally.

Of course, to achieve that immersion experience, you need excellent loudspeakers. But you also need a room with the proper geometry and acoustic treatment. The loudspeakers and the room together form a system. Tuning this system, getting the loudspeakers to work within a given space, is absolutely critical to the immersion experience. Tuning the loudspeakers to the room is the final, critical step in home theater setup. Improper or in-expert tuning can make a hash of the whole experience.

iDP Technology: Making Psychoacoustic Sense

When it comes to tuning a surround sound system to the listening environment, iDP (interactive digital processing) technology leaves nothing to chance. It gives AV systems installers full control over a fully active home theater system.

The Origins of iDP Technology
In early 2002, 75-year old English loudspeaker manufacturer, Tannoy, merged with Danish digital signal processing manufacturer, TC Electronic. Both companies identified in each other the essential technological expertise, in loudspeaker acoustics and digital electronics, for developing premium audio systems solutions for the residential and professional markets.

Tannoy re-engineered its patented, core technologies: the constant directivity, point-source Dual Concentric driver and the ultra high performance, WideBand SuperTweeter.

TC Electronic drew on its deep knowledge of digital signal processing and control technology.

The combination Tannoy’s and TC’s technological expertise resulted in the development of Tannoy iDP (interactive digital processing) technology and its first application in the Eyris iDP range of loudspeakers for the home theater market.

The concept of incorporating digital signal processing into a loudspeaker made its first appearance in professional studio monitoring for music and film mixing.

In essence, iDP technology allows a system installer to tune an individual loudspeaker/room system to match a specific home theater environment.

Not to be left out of the picture-or sound-for-picture-the home theater owner has access to various system pre-sets created by the installer. But primarily, iDP technology is an installer tool, and an essential one, for customizing a surround system to make psychoacoustic sense in a particular space and creating that home theater immersion experience.

iDP: What it Consists of

First of all, it is a powerful software package. iDP digital programming enables factory calibration of the frequency response of individual speakers to extremely tight tolerances-tolerances exceeding even the exacting standards of the professional monitoring industry. Every speaker in a surround sound system is established with its own natural voicing platform. It’s perfect, flat in both amplitude and phase.

iDP technology is also a loudspeaker system. Enough to say here, as realized in the Eyris range of loudspeakers from Tannoy, the iDP loudspeaker system incorporates two technologies that greatly increase accuracy and extended frequency range over conventional loudspeakers: Dual Concentric driver design and the WideBand SuperTweeter. The Tannoy Eyris loudspeakers are also bi-amplified.

iDP: How it Works

The iDP software package allows the installer to alter the precision, factory-defined frequency response for each loudspeaker and add delay to the system so that audio performance is perfectly matched to the acoustics of a particular home theater environment.

On-board digital processing allows the exact acoustic profiling of each loudspeaker, optimizing its performance relative to its location–whether that be in free space, close to a wall, in a corner, or in-wall. (Additionally, a loudspeaker placed against a padded wall is not going to perform the same as one placed against a glass wall.)

The iDP software has four bands of EQ with five different types of filters built in. It’s highly flexible, very much like a pro hardware or software based EQ system. The installer communicates (via a PC and RS232 connection) with each loudspeaker –in-place, in the actual home theater environment –and adjusts it to compensate for variations in room acoustics. Using the iDP software, the installer can get each speaker back to its ideal frequency response programmed in at the factory so it performs exactly the same, under real world conditions.

Similarly, programmable delay lines in the software can compensate for imperfect speaker locations. For e.g.: the LCR front loudspeakers in a surround system should function as a single, large loudspeaker, their aural information arriving at the listener/viewer’s ear at the same time. Often LCR loudspeakers are of unequal distance from central viewing/listening position. By physically measuring the distance from the loudspeakers to the listener’s ears, the installer comes up with a differential that he can correct by adding delay to the system, virtually changing the physical position of each loudspeaker in space.

In short, iDP technology eliminates the effects of the room and the effects of distance.

The System Owner

The system owner has access to the installer-defined pre-sets for AV or 2.1 stereo program – e.g. global volume, system mute, bass management, reference levels, etc.- via the display panel on each loudspeaker…

or by using industry standard network controllers such as AMX or Crestron.

Crestron ST-1700C wireless touchpanel

For the system owner, iDP technology and powered loudspeakers deliver audio-for-video with the need for an amplifier and all the wires that would connect to it. A DVD player and a system interface (such as the Crestron wireless controller) are all that’s required.

Currently the only incarnation of on-board DSP (digital signal processing) technology in a totally integrated residential audio system is from Tannoy. But the basic idea has turned up in offerings from other manufacturers. Expect DSP to find its way into other high-end surround sound products in the near future.

Tannoy Eyris iDP Loudspeaker System

Initially, the Tannoy Eyris iDP loudspeaker system is being offered as a complete home theater package for professional installation.

In its basic 5.1 configuration, the system consists of: four active Eyris iDP? DC3 floor standing loudspeakers with 500 Watts RMS to LF and 250 to HF; a DCC center channel with 500 Watts RMS to LF and 250 to HF; and a 1000 Watt subwoofer with two side firing, 12″ aluminum-coned drive units, and onboard iDP engine. However, the system can be configured in any combination and number of DC3’s and DCC’s. Networking facilities allow expansion for 5.2, 6.1, etc. and for future compatibility, the system can accept direct digital 192kHz inputs.

The DC3’s and DCC loudspeakers feature both Dual Concentric and WideBand technologies. The Dual Concentric driver offers phase-coherent, point-source sound reproduction and a 90 degree symmetrical dispersion pattern. Operating between the roll-off point of the Tannoy Dual Concentric high frequency unit and 54kHz, the SuperTweeter reproduces the leading edge of individual notes, allowing the listener to experience the entire bandwidth information of instruments. More information is available on both technologies at:

Charles Conte is president of Big Media Circus, a marketing communications firm.