Line 6 Case Study

Line 6 Dials in New and Vintage Tones for Guitarists using SHARC —

Guitarists are constantly searching for the "right" sound from their instrument to create a unique style or emulate the sound of a noted player. This elusive search can lead to 'chronic gear syndrome', a tangle of expensive boxes, patch cables, guitars and amplifiers that promise to deliver the desired sound. Trial-and-error gear-collecting and patching was the only approach before Line 6 revolutionized the electric guitar effects industry with its innovative POD^® guitar processors. Rather than a single effects box, the POD could produce a wide range of effects (tremolo, reverb, flanging, delay, chorus, etc.) and could also produce the characteristic clean and overdriven tones of history's most desirable amplifiers (without setting the knob to '11' !!)

The technique they pioneered is called "modeling" - which uses a series of complex digital algorithms to emulate the analog circuitry found in traditional "stompboxes," vintage guitar effects units and the characteristics of vacuum tube power amplifiers. Line 6 approaches the challenge of delivering the "right" tone by developing powerful digital signal processing algorithms derived though painstaking measurement and analysis of the most highly regarded amplifiers and other gear from the recent past, the not-so recent past, and today. Line 6 has analyzed so much equipment that they have a unique perspective on the components of 'tone'. Since one 'tone'-producing component is often used in conjunction with other components (stompbox with amp with reverb or rotating speaker), Line 6 provides presets of popular gear combinations, as well as combinations that they have only encountered in their development lab. This process is quite complex, and requires a deep understanding of the art and science of 'tone'.

LINE 6 have been pioneers in the field of digital signal processing for musicians. From the introduction of the original POD in 1997, LINE 6 has changed the way musicians and recording engineers approach guitar effects. Digital modeling has opened up the availability of authentically vintage sound and has allowed creative musicians to experiment with effects that are only available through modeling. LINE 6 has expanded the technology to include several lines of amplifiers and modeling guitars, both electric and acoustic.

In order to flawlessly deliver these levels of signal processing at the highest quality, Line 6 required a processor powerful enough to deliver the performance needed, and be flexible enough to accommodate many different modeling algorithms.

"Beginning with our first product to utilize an Analog Devices DSP, the Vetta^™, on through our latest SHARC based products, like the M13; the power, flexibility, and ease of use of the SHARC has allowed for quick prototyping and creative experimentation. The freedom and calability of the SHARC has aided us in the advancement of our modeling technology and has given us the ability to better serve the customer with more sophisticated features and capabilities." Angelo Mazzocco, Lead DSP Engineer. "We also depend heavily on the extremely useful and well equipped Visual DSP debugger. It has become a crucial part of our development process."

SHARC features built in peripheral devices including SDRAM interface and DMA controllers, for connecting to external RAM. The integration of key peripherals is important not only for performance reasons, but also contributes to reducing bill of materials, power and PCB area.

For the new Spider Jam^™ and JM4^™ products, the SHARC is playing a central role in these systems and we decided to employ Analog Device's VisualDSP++ Kernel. We enjoyed the benefits of having flexible real-time operating system with great integration with the VisualDSP++ environment. As stated by Senior Embedded Engineer, Joe Sarlo, "The VDK is nice in that it gives you things like threads and semaphores in a really easy-to-use way, without having to deal with a bunch of other features you don't need or changing how your code is structured. In other words, it's nice and modular so you can use just the parts you want."

Line 6 develops its products using Analog Devices' Crosscore Development Tools and VisualDSP++. They have developed a proprietary signal processing kernel and code libraries that contain the algorithms and parameters that produce the carefully researched and developed Line 6 models. Line 6 currently uses SHARC processors in more than a dozen products, and it is continuing to introduce new models and products based on SHARC processor technology.