Sounds, Programs, and Mixes

Understand the relationship between samples, sounds, Programs, and Mixes before planning your QSR Drum Synthesizer.

This topic covers important concepts and terms related to the differences between samples, sounds, Programs, and Mixes in the QSR.

Links to sections in this topic The concepts discussed in this topic can be confusing but here are the key takeaways:
  • The QSR uses samples to create sounds.
  • Programs determine which sound plays based on MIDI note numbers.
  • Mixes assign different Programs to MIDI channels.

Samples and Sounds

A sample is a digital file that represents the waveform of a sound. Samples come from several sources. A short recording of an instrument can be used as a sample file. Electronically-synthesized waveforms can be used as samples.

In the context of the QSR, a sound is the combination of a sample and its associated processing. Several functions in the QSR (filter, amplitude envelope, pitch envelope, LFO, multiple modulation sources, signal processors, etc.) are used to process a sample file.

The QSR has 16 megabytes of sound ROM (Read Only Memory) containing built-in, digitized, acoustic and electronic samples. The QSR contains a variety of instruments, including drums and percussion. The QSR's samples are organized into 17 Sample Groups of different types. To use the built-in samples in an edited Program, you first select the Sample Group and then choose the name of the sample you want to assign to a sound layer in your Program.

The available built-in sample groups are listed below:

Table 1. Standard QSR Sample Groups
Piano String Noise Sound FX
Chromatic Brass Voice Rhythm
Organ Woodwind Ethnic  
Guitar Synth Drums  
Bass Wave Percussion  

The Drums and Percussion Sample Groups contain a variety of samples that are used in the built-in drum Programs. You can also use these samples to create your own custom drum Programs. However, due to the low quality of some samples, you will probably want to add your own custom samples as well. The QSR makes an ideal platform for creating a drum synthesizer, partly because of its ability to use custom samples—a feature typically found in only high-end sound modules.

Programs and Mixes

To get the most out of the QSR, you will need to understand the differences between Programs and Mixes. People who have previously used a synthesizer can usually understand the concept of Programs but many get confused by Mixes.

The QSR Reference Manual describes Programs and Mixes:

A Program is a stored configuration of parameters which emulates the sound of an instrument or sound effect, such as a piano or synthesizer or drum set. A Program may have from 1 to 4 different sound layers, each of which can use different samples. Programs can combine sound layers in a variety of ways to create the sound of the instrument the Program is intended to emulate. You can layer the sounds on top of one another, split the layers up into different sections of a keyboard (note ranges), or use different sound layers depending on how hard you play the keyboard or drum (this is known as velocity crossfading).

A Mix is a combination of 1 to 16 Programs. The Programs can be combined in many ways. The most common is multitimbral, which means that for each MIDI channel the QSR receives (up to 16), a different Program may be selected, thus creating anything from a small pop/rock ensemble to a complete orchestra (or a drum kit). Another way of using a Mix is by layering two or more Programs together, so that they play simultaneously from your MIDI controller. You can also create a split, where one Program is in the lower half of your keyboard, while another is at the top half; and these programs can even overlap in the middle.

Built-In Programs and Mixes

The QSR provides 640 built-in Programs, divided into 5 Banks of 128 Programs each. More Programs (and custom samples) can be added using a PCMCIA Sound Card in the card slot on the front panel. We will use a PCMCIA card to store our custom samples, Programs, Mixes and Effects.

The QSR also stores 100 Mixes in the User bank and 400 Mixes in the Preset and General MIDI Banks.

Drum mode versus Keyboard mode

Each of the four sound layers within a Program operates in either Keyboard mode or Drum mode. Programs developed for keyboard applications (e.g., piano or synthesizer programs) typically use the standard Keyboard mode. Keyboard mode allows the full range of the keyboard to be mapped to individual sounds or samples, which you can play using a single MIDI channel. You can also split the keyboard by using two sound layers in the Program, each set to respond to different ranges of notes (overlapping or not).

Alesis also uses the Keyboard mode to create drum kits that comply with the note number assignments in the General MIDI standard. You can use the built-in QSR kits but you cannot edit them without expensive editing software. So we will use Drum mode throughout this Manual for programming.

Drum mode changes the nature of the voice function in the QSR and adds features used when creating drum kits. You can set Drum mode for one or more, or all, layers within a Program.

In Drum mode, individual drum samples cannot be “stretched” across the entire range of the keyboard.

In Drum mode, each of the 4 sound layers provides 10 sound slots. Each slot has a single note number assignment. You can assign 10 different drum sounds (to 10 different note numbers) in each Drum mode sound layer. If all four sounds in a Program are placed in Drum mode, you could assemble up to 40 drum sounds.

Within each sound layer, you can use a MIDI note number only once. However, you can use the same note number in each of the four sound layers. This allows layering of individual drum sounds and velocity crossfading.

One advantage of using Drum mode stems from the fact that each of the 10 sound layer slots has its own set of parameters (Pitch, Filter, Range, Effects Level, panning, etc.). You can adjust the parameters for each slot independently. In Keyboard Mode, the processing functions available apply to all sounds in the Program. So, for example, if the snare sound in a built-in, Keyboard mode drum kit is too loud relative to the kick drum you cannot adjust its level or panning without affecting the other drums. The ability to adjust individual drum sounds makes Drum mode ideal for programming our drum sound module.

Drum Programs

Keyboard mode is often used for drum kits that are compatible with the General MIDI standard. The built-in drum kits in the QSR use Keyboard mode to support the General MIDI standard. The QSR Reference Manual explains that in Keyboard mode, if you select a kit (such as “Rock Kit 1”) as the voice of a Program sound, an entire arrangement of preset, pre-mapped drum sounds will be assigned across the keyboard. If you select a single drum (such as “Timpani”) as the voice, that single drum sound will sound across the keyboard range, with a different pitch on each note (the original sample pitch will appear on C3).

The QSR is a perfect General MIDI companion, since its Mix Mode uses 16 channels. Although many channels are commonly used for specific types of instruments (Example: Channel 1 is usually piano, channel 2 is usually bass, etc.), channel 10 is always used for drums. In the General MIDI standard, drum sounds are assigned to predefined note numbers, ensuring consistency and interoperability.

Drum mode simplifies the task of making up your own drum kit, whether you use custom samples or the selection of over 340 different built-in drum samples. The QSR contains 21 kicks, 26 snares, 33 toms, 43 cymbals, 75 percussion, 83 percussion effects and 63 synth waves.

In the drum synthesizer Programming Strategy described here, we will not use Keyboard mode. Rather, we will use Drum mode in our Programs. But we will follow the General MIDI note number standard where possible.

Drum Mixes

The QSR plays sounds in either Program or Mix play mode. In Program play mode, a single MIDI channel controls the Program. Each MIDI Note On command on that MIDI channel triggers a different sound. Sounds can be layered or assigned to different note numbers or ranges.

A Mix, on the other hand, combines multiple Programs on a channel-by-channel basis. In Mix play mode, the MIDI channel determines which Program is used. Mix mode was created to allow sequencers to control the QSR. In Mix mode, the QSR plays back different instrument sounds in response to different MIDI channels. For example, one might create a mix using channel 1 for piano, channel 2 for bass guitar, and channel 10 for drums (typical when General MIDI instruments are used). Because of its 64 voices and built-in effects, the QSR can simultaneously generate multiple instrument sounds.

This multitimbral feature is extremely useful when creating a drum synthesizer sound module. The QSR could simultaneously play multiple drum sounds using a single Program, within limits, but if we also separate different drum groups (snares, toms, kicks, cymbals, etc.), placing each on its own MIDI channel, then we can use Mix mode during playback and gain the ability to independently change the sounds of each drum group.