Audio Engineering Society

Chicago Section

Meeting Review, May 2nd 2001

other meeting reports

5/2/01 Meeting Highlights
by Bob Zurek

DSP in the Installed Sound Market

On May 2nd, Chicago Section Chair Marty Reiling of Shure Inc. gave a presentation about digital signal processing in the installed sound market. Marty started off this presentation by going over some of the DSP applications and products he saw at this year’s NAB show which he dubbed “ the year of the DSP.” Marty observed that whole racks of equipment are being replaced by single DSP components in both the fields of audio and video. Not only were products shown in the older established areas like delay, FX and amplifier control, but also new consoles with built in DSP were shown. Mr. Reiling then went on to discuss the customer requirements as well as the established, new, and experimental applications of DSP in the Live Performance, Broadcast, and Studio markets. Marty then went on to the church and stadium installed sound market applications. For the Church market, he reviewed the established usage of DSP, and then discussed new applications for this market such as delay, notch filters, and complete “sound in a box” systems. HE also briefly discussed experimental application of DSP in the church installed sound market such as wireless microphones with DSP and integrated echo cancellers. As with the other markets, Marty covered the past applications of DSP to the Stadium sound market, and then went on to discuss new and experimental applications like the “sound in a box” concept, and digital audio networking. Next, Mr. Reiling discussed the challenges a DSP manufacturer faces from creating good analog sections to acquiring of hiring the right expertise to get the project done. Marty mentioned that these challenges must be met while keeping a realistic perspective in the marketplace. The engineers and product manager have to ask themselves the questions: “what are we reproducing?” and “what can we actually hear?” These two questions will lead to the appropriate specifications and design. Marty then posed the question of “why not do DSP on a PC?” The answer boiled down to the facts that the engineer can do a better job with a dedicated box, and of major importance to the installed sound market, make a unit with a crash-proof operating system. The issue of grounding and shielding in a DSP box was addressed. Mr. Reiling observed that shielding in DSP needs more attention, and that “every DSP device is an unintentional RF radiator.” Marty also observed that unlike most analog systems, DSP products are a group effort requiring the input of diverse backgrounds, such as analog and Digital Hardware engineers, software coders, documentation writes, and ergonomics and human factors experts. In addition to these specific personnel needs, the project also requires investment in development tools, management, and measurement tools. Marty commented that many of the DSP disadvantages of the past are going away, and the market is moving from fixed path boxes to the new GUI controlled reconfigurable one’s on the market today. He also quelled some of the DSP myths that have evolved over time such as: the number of chips means more processing capabilities, and that adding more processing modules increases delay in the system. Marty then demonstrated a few of the boxes available on the market today, which had GUI’s that varied from powerful but difficult to use schematic capture type interfaces to easy to use drag and drop interfaces like the Shure P4800 SoundplexTM system processor. The meeting concluded with an informative question and answer session.