Alesis QSR 64 manual About Modulation

Editing Programs: Chapter 6

AMP

Each voice/filter combination is followed by an amplifier whose level can be controlled by a variety of modulation sources. This allows for creating sounds with percussive or slow attacks, particular types of decays, tremolo, etc.

Filter and amp settings can interact. If the filter cutoff is extremely low, then no signal will get through, no matter how the amp is set. Similarly, setting the amp for a short decay won’t let you hear any filtering set for a longer decay. This is because the volume will reach zero before the filter decay finishes.

ABOUT MODULATION

Modulation modifies some aspect of a sound over time. Since oscillators make static sounds (unlike acoustic instruments, whose timbre and dynamics change—often radically—over the duration of a note), modulation is the key to making rich and expressive sounds. The vibrato of a flute, the expression pedal of an organ, a wah- wah pedal on a guitar--all of these are examples of modulation. You're probably familiar with the mod wheel of a synthesizer, which typically adds vibrato to a Program as it is raised. But in synthesizer programming, modulation is used to control even the basic characteristics of a voice: its attack, decay, and release times, for example. Every box in the signal diagram on page 49 pointing towards the Voice, Filter, or Amp boxes is a modulation source. The amount of modulation, the time it takes place, and what controls (such as key velocity, footpedals, aftertouch, mod wheel etc.) affect it are important parameters in every Program. The QSR provides the modulation flexibility of patch cord-based instruments, but with the convenience and ease of use of digital technology.

With some parameters, the modulation amount can be positive or negative. A positive control signal increases the value of the parameter being controlled. A negative control signal decreases the value of the parameter being controlled. Setting modulation to 00 turns off the modulation source. Example: Keyboard velocity can either make a sound brighter the harder you play, or make it less bright, or have no effect on the Filter at all. You have the freedom to set modulation any way you want, even in ways that are the opposite of what they would be on an acoustic instrument.

If a “baseline” setting exists for a parameter, modulation amounts add or subtract values from the existing setting. However, modulation cannot force a value beyond its maximum range. For example, if the Amp is already at its minimum value (lowest level), you could apply positive modulation to raise the level. But applying negative modulation will not affect the Amp level, since it's already at its lowest value and cannot go any lower.

The QSR lets you assign several modulation sources to one modulation “target” parameter, which allows for interaction between two modulation signals. Example: If the Amp parameter responds to both the envelope generator and a pedal, the parameter will follow the general envelope shape but will also be influenced by the pedal.

QSR Reference Manual 5