COSM Revisited A Fresh Look at the Amazing Modeling Technology Inside BOSS and Roland Guitar Products By Jim Bybee If you own, or are shopping for, a BOSS guitar product (or one from BOSS’ parent company Roland), you’ve probably seen the “COSM” acronym in some documentation and even on the products themselves. At first blush, you might think it’s just a simple marketing tag; however, it’s much, much more than that. COSM—which stands for “Composite Object Sound Modeling”—is the complex digital technology at the heart of amazing guitar devices such as the VG-99 V-Guitar System, GT-10 Guitar Effects Processor, and MICRO BR BR-80 Digital Recorder, just to name a few. It’s also the backbone of revolutionary Roland “V” instruments like the V-Drums, V-Synth, V-Piano, and more. Here, we’ll take a brief look at the proprietary modeling technology that’s been at the core of so many BOSS and Roland processors and instruments for so many years, with a focus on its use in guitar and bass products. The Roots of COSM Roland first developed COSM for the VG-8 V-Guitar System, which was introduced way back in 1995. The VG-8 was truly a milestone for the guitar products industry, the very first device to incorporate digital modeling in a guitar processor. While modeling is commonplace in the guitar world today, the VG-8 and COSM represented jaw-dropping technology at the time, blazing a new path that quite literally changed the music landscape moving forward. The VG-8 was such a revolution because it took the sound from a guitar’s six individual strings—captured via a special GK divided pickup—and processed them on multiple levels, all while retaining the guitar’s natural feel and playability. First, there was instrument modeling, which recreated the actual sound characteristics of many different electric and acoustic guitars, plus entirely new sounds achieved with a process called HRM. In addition, the strings could be pitch-shifted and doubled on an individual basis, allowing for instant altered tunings and 12-string effects. From there, the signal could be processed through an arsenal of virtual guitar amplifiers. This now-familiar concept was simply astounding at the time, and the ability for a guitarist to call up any classic amp at will—along with a perfectly mic’d speaker cab—was like a dream come true. Of course, the VG-8 also included a host of effects processing to sweeten the sound even further, including COSM stompbox effects and more. Moving Forward After the VG-8, COSM became the leading technology in BOSS and Roland guitar products. This continues to this day, and COSM is continually being developed and refined to expand its potential. In particular, COSM amplifier and speaker modeling is an essential part of an enormous range of past and present products, from BOSS GT- and ME-series guitar effects processors to BR recorders to Roland’s CUBE amps. Among the biggest benefits of modeling is the ability to record great guitar sounds direct, without having to hassle with mic’ing up an amp and dealing with loud volumes. This is something that us guitarists take for granted these days—but it all started with COSM! COSM instrument modeling for guitars has been continually developed as well. The latest products that incorporate this technology include the Roland GR-55 Guitar Synthesizer and the current V-Guitar System, the VG-99. There’s also the VB-99 V-Bass System, which brings the world of COSM instrument and amp modeling to bass players. While first developed for guitarists, COSM has been the basis for other groundbreaking Roland instruments. In 1997, V-Drums changed the percussion world just as the VG-8 changed the guitar world. Featuring COSM virtual drum sounds and ultra-responsive mesh-head pads, V-Drums became the leader in electronic drums overnight, and they’ve remained so ever since. More recently, the V-Piano and V-Piano Grand incorporate an offshoot of COSM to create their amazingly responsive and realistic piano sounds. Of course, COSM is used in many other instruments, as well as effect units such as the BOSS VE-20 Vocal Processor. Let’s Get Physical COSM is actually an amalgamation of many different digital modeling technologies developed by BOSS and Roland. These were created to precisely model the electronic, mechanical, and magnetic characteristics inherent to an instrument, amplifier, or speaker, and also to create completely new sounds. In concept, the COSM process is not unlike the amazing computer-generated imagery (CGI) we all see in today’s high-tech films, where complex software is used to digitally construct people and animals from the inside out, from skeleton to muscles to skin. COSM models all aspects of an amp’s circuitry—every component, every path. Variable Guitar Modeling, or VGM, is the main component of COSM when it comes to guitars and basses. It can be broken down into three separate elements: Electronic modeling—With this process, BOSS and Roland engineers analyze and simulate the actual electronic circuitry and how it interacts in a device such as a vintage guitar amp or a classic stompbox. This includes the detailed behavioral characteristics of vacuum tubes, transistors, and all other electronic components. Magnetic modeling—Electromagnetic components are a huge part of the sound of electric guitars and amps; this VGM process simulates the characteristics of guitar pickups, amp transformers, speakers, and more. Physical modeling—This process is a central part of COSM instrument modeling. It simulates the characteristics of the materials used to construct an instrument, including the type of wood, the metal parts, and even the finish. Physical modeling is also used to analyze the construction materials used in different guitar speaker cabinets. Measuring sound in an anechoic chamber. Harmonic Restructure Modeling (HRM) is another component found in some COSM guitar products. The vibration of a guitar string generates many harmonics, and these harmonics define the actual sound character of guitar sounds as we recognize them. With HRM, BOSS and Roland engineers manipulate these harmonics and change them to create very un-guitar-like tones, while still retaining feel and playability of the guitar. In a Roland V-Guitar System, for example, HRM applies the harmonic characteristics of organs, reed instruments, and synths directly to your actual guitar. When all the VGM and/or HRM elements are brought together, the result is a realistic composite of the individual components of the object whose sound is being modeled. That’s a real mouthful, so COSM’s extended name describes this process much more elegantly: Composite Object Sound Modeling. Get it? Realtime, All the Time COSM accomplishes all its modeling magic in real time using super-fast digital signal processing to alter the guitar’s sound as you play. Your guitar’s string signals are the fundamental building blocks of the sound you hear, even when the real-time modeling process modifies that sound into something quite unlike a guitar. As such, COSM retains the natural feel and responsiveness of your guitar playing, with every subtle, expressive nuance coming through. If It Sounds Good, Play It Well, there you have it—a brief introduction to the amazing COSM technology. Rest assured, there are a lot more details to this story, but getting into them all would add up to a book! As a player, all you really need to know is this: COSM equals unparalleled realism and great sound quality, thanks to nearly 20 years of continuous research, development, and refinement. So, the next time you see the COSM logo on a BOSS or Roland guitar product, you’ll know you’re getting the first—and still the best—digital guitar modeling available.