The ROLAND D-550 is very different from any other synthesizer, past or present, and as such heralds the dawn of a new era in synthesis. In the past, synthesizers have progressed through severalvery diffrcnl stages. Firstly, there were ANALOG synthesizers, which relied on a variety of components, such as, VCO's. VCF's, and VCA's. These analog building blocks were relatively easy to understand and program, and they could produce sounds of remarkable warmth and character. However, when it came to accurately simulating acoustic sounds, the process could easily become too involved.
On the other hand, the next breed of synthesizers, known as DIGITAL synthesizers, could easily simulate acoustic sounds, yet they were far more difficult to program. Furthermore, the digital technology behind these instruments seemed to imply that a different type of sound should occur. In general, just as an analog synthesizer would be described as "warm" in character, the digital counterpart was very often "thin". Essentially, the two types complemented each other, one being easy to program, the other capable of accurate simulation.
The ROLAND D-550 has now changed all that. Thanks to a new custom disigned Integrated Circuit known as the 'LA CHIP*. Here, LA stands for Linear Arithmetic synthesis which is the heart of the new technology. LA synthesis involves a great many technological advances resulting not only in a superior sound quality but also an improved ease of programming. In this way, Roland has succeeded in maintaining a high degree of familiarity to the user despite the technical wizardry involved.
To explain the D—550 in a very simple manner, we must begin by saying that it is the next step in DIGITAL synthesizers. This means that the sound is entirely computer generated. In fact, the D--50 has four distinct sections :
Remember, first of all. that this isa totally digital instrument, even though the sound would seem to suggest far more. Through LA synthesis, the D-550 appears, to have four powerful synthesizers built in. Each of these hypothetical synthesizers could behave like a conventional analog synthcizcr, or a PCM sampled synthesizer. Consequently, they are referred to as PARTIALS. since they are far more than just a pure synthesizer. These Parlials are combined in pairs to form a TONE. A Tone could cither be a mix of the two Parlials. or they could take advantage of the LA version of cross modulation. In this way, some of todays more popular digital sounds are remarkably easy to achieve.
However, it is the performance characteristics such as after— touch, and the control of every aspect of the sound that makes the D — 550 a totally new instrument. These things and a sound that can only be described as unique, the LA sound.