Fifty people attended AES San Francisco's June, 2004 meeting, at Universal Audio (UA) in Santa Cruz, California. The speakers were David Crane, Sean Lamb, and Dr. David P. Berners. They are: Training Manager, Materials Manager, and Director of Algorithm Development, respectively.

David Crane gave an overview of UA’s history and philosophy. Much of UA’s approach to sound engineering is inspired by the pioneering work of Bill Putnam, an industry leader in the 1960s and 70s. Mr. Putnam developed techniques that modern-day audio professionals take for granted, such as multi-band equalization, half-speed mastering, and acoustically isolated booths for recording vocalists.

One of UA’s main businesses is selling re-creations of classic audio gear, such as preamps and limiters. Sean Lamb explained some of the challenges involved in reproducing the Teletronix LA-2A Leveling Amplifier. The heart of the LA-2A is a cadmium-sulfide photocell, which proved to be difficult to reproduce. Ironically, this was due to advancements in its design and manufacture. Current versions are too fast, compared to the original version of the photocell.

UA makes software which emulates a wide range of audio devices, with an emphasis on vintage audio. Dr. David P. Berners talked about methods for characterizing signal processing gear digitally. Simply comparing the output of a device with a variety of inputs, is useless. An infinite number of input signals would be necessary. Functional modeling is the best approach, as it takes into account what is really happening inside the device. With an accurate model of how a device behaves, it is possible to create a convincing emulation in the digital domain.

One of the challenges in emulating audio devices, is that different units of the same model, by the same manufacturer, sound differently.

UA also manufactures a PCI DSP card, with many plug-ins, claimed to simulate a range of well-known audio processing devices. UA’s computer card contains sufficient processing power to avoid swamping the user’s computer CPU.

by Paul Howard