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STRATOMATIC ROCK-N-ROLL
by DAVID PLUM, Phd

After 23 years in development, David Plum, Phd. has
released a White Paper in support of the pending
release of Strat-o-Matic Rock 'n Roll,
a virtual band development, composing, and recording tool


Although I respect the work Pete Townshend and his developers have been doing," said Plum in a recent interview, "their software will allow users to create little more than a musical self-portrait. That's cool, but what rock 'n roll fans really want to know is, 'What would a band with Jimi Hendrix, John Bonham, John Entwistle, and Gary Rossington sound like?'"

What Strat-o-Matic Rock 'n Roll offers is not only a chance to form these Supergroups but, through the software, to accurately simulate the writing and recording of original music. The possibilities are endless, but the best way to understand exactly how this works is to study the following White Paper. Plum will be available to field your technical questions via email.


Stratomatic Rock-n-roll involves a combination of Linear Predictive Coding techniques for modeling vocal tract formant frequency acoustics,


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Blind Adaptive Filtering analysis and reproduction of numerous amps. guitars, acoustics, etc,


Neural Networks for "on the fly" performance creation and modeling of a wide range of rock-n-roll styles.

Because of the compute intensive nature of the various algorithms used to process a performance, massively parallel hardware is required to run in real time. These algorithms, described using pure untimed C++, were taken directly to synthesizable RTL by using the industry leading high-level C++ synthesis tool. The auto-generated RTL is then synthesized, placed and routed, and then run on a standalone Altera Stratix-II FPGA based platform. This is what we refer to as the Stratomatic Magic Box. The Magic Box can be run as a standalone platform for live performances, or can also be interfaced with a PC using either light pipe or Firewire interfaces. The Stratomatic performance engine can run as an independent application or as an AU plug-in under Logic, Pro Tools, etc.

Stratomatic Rock-n-roll has two primary modes of operation, performance mode and accompaniment mode.

In performance mode the user drives the song creation process by selecting the instruments and instrument styles. Pre-canned templates are provided for quickly creating either general period sounds or specific instrument arrangements e.g. Song Template > Beatles > Rubber Soul > I'm Looking Through You. Once the initial instrument tracks have been created the user can drive the song creation by adjusting parameters on the performance engine. The performance engine has been designed to operate on a simplified set of constraints for the beginner or non-musician. These constraints consist of general purpose constraints such as mood, rhythmic style, room, etc. These general purpose constraints run a number of heuristic algorithms based on the instrument performance settings. Once the initial constraints are set the user simply clicks on the Generate button and the song is created. For the novice this may be the last step in the song creation process, however there are a number of additional optimizations available to the advanced user. When running in simple mode, the vocals are auto generated using the performance database, vocal tract models, as well as a specialized phrasing engine that mimics vocal inflections of many of Rock-n-roll's best vocalists. The limitation with this mode is that the lyrics are drawn from a limited database of about twenty songs, leading to a limited number of vocal possibilities and themes. There is some room for customization here, but advanced users will probably wish to cut their own vocals. Users can run their own vocal tracks through the Stratomatic vocal algorithms. This will extract a baseline excitation that is then fed though a user selectable vocal tract model. The phrasing engine will post process the reconstructed vocal applying stylistic vocal transitions. Auto pitch detection and correction algorithms are also run with no artifact insertion. This approach usually leads to more natural sounding vocals.

The other operational mode is accompaniment mode. This is a real-time mode that allows the user to play their instrument of choice with Stratomatic providing the back up. This mode uses many of the same performance settings used in performance mode to allow the specification of instruments sets, tempo, style, etc. The key technology that differentiates accompaniment mode is the "learning engine" The learning engine processes the user's input instrument in real-time and performs causality analysis to adapt the instrument set to match the user's style. Advanced foot pedal control is supported to allow the user to drive the performance engine when things like guitar solos and drum fills are desired at specific places in the performance.

David Plum, Phd. holds advanced degrees in both Electrical Engineering and Computer Science and is currently working in the field of high-level synthesis and electronic system level design.