It’s a sad fact, but true: stereo imaging doesn’t scale well in larger spaces. Due to level offset and distance factors, the typical small sweet spot of a living room environment remains almost the same size when played through a conventional sound system in a large auditorium. While a few choice center seats will experience the spatial imaging that defines a non-monaural mix, the vast majority will be subjected to an unrealistic combination of sources that do not represent the true nature of the performance. Thus, most performance audio systems are operated in a mono mode that sends an identical signal to each loudspeaker, yielding an egalitarian, but bland sound across the venue. Several manufacturers have made an attempt to alleviate the problem, but no single technology has proven effective, until TiMax.
Spreading the sound source far and wide is what TiMax is all about. How it achieves what the company terms Source Oriented Reinforcement (SOR) is based on the realization that localization involves not only level (volume) matrixing, but time (signal) delay matrixing as well. In fact, it is this combination that defines TiMax as a unique technology, one able to address spatial imaging in real time and in a variety of acoustic environments.
The crux of the TiMax innovation is its use of the precedence effect. Also called the Haas Effect, in honor of its first empirical observer, precedence states that a sound source delayed relative to an identical source by more than 1mS, but less than 30mS will “disappear” to a listener seated between the sources. If the delay is increased beyond 40mS, the delayed source will reappear as an independent device to the listener, but with an adverse effect on intelligibility. Thus, a signal delayed by up to 30mS will fuse with the direct signal in the perception of the listener, even if the delayed signal is louder. Therefore, the first arriving signal takes precedence over the delayed signal(s) and is the sound the listener will acknowledge as the source.
TiMax engineers use this phenomenon to pan signals across a large listening environment and have furthered their success with the implementation of the Kuttruff Effect that states multiple sources can be delayed by a summation greater than 30mS without loss of intelligibility through the strict adherence of sub-30mS delay times between individual signal sources. In use, this allows speaker B to be delayed by 30mS relative to speaker A while speaker C is delayed by 30mS relative to speaker B. As a result, speaker C is 60mS behind speaker A, but the Haas Effect between A and B and that between B and C tie them coherently together. The TiMax system pans and delays multiple speakers in a room through a rather complex matrix that gives the operator a deft hand in creating localized material for the majority of the audience. The TiMax system arrives as the proverbial “black box,” in an eight-rackspace (8U) card chassis that connects to a rack-mounted PC running Windows 95 or Windows 98SE (don’t laugh – it’s stable) via a parallel cable. As is common with many DSPbased units, the TiMax system can be ordered with a varying number of I/O cards (up to four) sporting analog or digital interfaces, with eight I/O ports per card. Converters are 24-bit resolution and use XLR balanced connectors for analog cards and AES/EBU ports on the digital cards. Two new non-modular configurations have recently joined the range in the form of the lower cost TiMax ImageMaker8 (3U 8x8) and ImageMaker16 (4U 8x16).
If there is any doubt as to TiMax’s origins, they are dissipated at the first sight of the manual, which demonstrates TiMax’s undeniably British heritage. The 1602 Group LLC, a company formed from a recent buyout of Solid State Logic’s Pipe Organ System business, distributes TiMax in the USA. The product is ably supported by the audio gurus at the company’s Virginia headquarters.
Building a piece of hardware is one thing; crafting a software interface that works is quite another. Fortunately, the TiMax team spent a great deal of effort on making the interface as elegant as the actual workings. As a theater-oriented product, TiMax is designed to handle numerous shows and their accompanying array of cues. To that end, the software allows detailed information about each actor, channel, and MIDI-triggered effect (up to sixteen per cue) and CD tracks to be stored in simple English as part of the show control data stream. The matrix screen is a straightforward mouse-controlled affair with ease of setup as its primary consideration while the play list is a scrolling cue arrangement that gives pertinent information at a glance.
Setting the TiMax system to accurately convey stage placement of instruments and voices is accomplished through designing Image Definitions. Essentially a relationship among speakers, the Image Definition conveys the level and signal delay settings each speaker should receive based on its proximity to the acoustic source. Hence, the speaker closest to the source receives the least amount of delay while the farthest speaker gets the greatest delay with the pretense being a continuously localized signal should be available to each listener, regardless of seating position. An intuitive drag-and-drop scheme is used in the most amazing section of the system: the Effects Screen. Here, pulling icons that represent the various inputs around to various locations on the Image Definitions results in the aural “placement” or localization of the source or continuous movement multiple aural images among the loudspeakers, if movement is the effect you want to achieve. Thus, the total number of speakers in the system is the only limit to surround sound, not a predetermined format such as 5.1.
For its trial run, we set up the TiMax as a support network in an Atlanta area Wal-Mart that had been converted for use as an Easter Sunday venue with seating for 4,000. Faced with the obvious acoustical challenges of a department store turned worship space, the sound system employed a four-ring delayed loudspeaker array comprised of JBL SR-X Series, Apogee AE-9 and subs, and AA ILS-1264 cabinets powered by Crown MA Series amps fed by two Crest X-VCA consoles with Klark Teknik and Lexicon outboard gear. The system controller was a prototype of the upcoming Architectural Acoustics Digitool running in LMS (Loudspeaker Management System) mode.
When the TiMax arrived on-site, the sound system was up and running, making a before-andafter comparison easy. After a few obligatory computer technical difficulties, the TiMax roared, or at least whirred, to life and the critiquing began. Since the musical portion of the service revolved around the forty-piece orchestra from the host church, Wildwood Baptist, there was ample opportunity for source orienting the sound reinforcement. The result was subtly profound, with an obvious improvement in the mix, of the clarity of each instrument, as well as a welcomed reduction in the overall SPL required to achieve “fullness.” The system worked without failure and added to the service a much-needed dimension to the spartan surroundings. While it did not transform the Wal-Mart into one of the world’s renowned acoustical spaces, it did make a marked difference perceivable to even the most casual listener.
In use, the TiMax does what its creators claim and performs its duty with great audio clarity. While it will not find its way into every worship venue, it does have its place in churches and large-scale arena-style worship venues. For a church with a strong drama and music department, excellent audio and video systems, and a competent technical crew, the TiMax system just may be the next logical step in improving system performance, and, hopefully, the message’s impact.
The editor would like to thank Art Yeap of NOVO Group in San Francisco, CA for his help with this article.
