About the QSR

Learn what makes the QSR an ideal drum synthesizer sound module.

This topic introduces the QSR synthesizer and discusses features that are useful for creating a drum synthesizer sound module.

Links to sections in this topic

What is a QSR?

The Alesis QSR, a rackmount synthesizer introduced in 1997, was an extension of the Quadrasynth (QS) series. The QSR is a 64-note, polyphonic synthesizer that uses wave-table (sample-based) synthesis. It uses the same synthesis engine as the QS7 and QS8 keyboards but fits in a single rackmount space. The QSR offers 16 megabytes of built-in sounds in its internal ROM. You can easily expand its sonic library by plugging a PCMCIA Flash RAM card into its dual expansion card slots.

Features and Specifications


  • Large, easy-to-read display,
  • Enhanced General MIDI sound set
  • Hundreds of sounds and multitimbral mixes
  • Includes Alesis' acclaimed stereo grand piano sounds
  • 64 voice polyphony
  • Front panel interface for performing, programming and editing
  • Expansion card slots for adding an additional 16MB of new sounds, and
  • Sound Bridge software for adding your own custom samples
  • ADAT Optical Digital Interface and Serial Data port
  • Play back up to 100 Standard MIDI File sequences without any external sequencing device


  • Sound Generation Method: 16 Bit Linear 48kHz Sample ROM
  • Synthesis: QS Composite Synthesis ™
  • Voices: 64, each with sweepable low-pass filter, 3 envelope generators, 3 LFOs, programmable effects send and QS Modulation Matrix, dynamic voice allocation
  • Available Waveform Memory: 16 MB, expandable to 32 MB via PCMCIA Expansion Card Slots
  • Program Memory: 512 Preset, 128 User Mix Mode (400 Preset, 100 User)
  • Effects: QS Parallel Matrix Effects™ (4 independent stereo multi-effect processing busses)
  • Multitimbral Mode: QS Mix Mode (64 Part multitimbral across 16 MIDI channels)
  • Expansion Slots: PCMCIA card slots, QCard and Sound Bridge compatible
  • User Interface: Backlit custom LCD display
  • MIDI Connections: MIDI In, Out, Thru.
  • Audio Outputs: Main L/R (1/4”), Aux L/R (1/4”), Headphone (1/4” TRS)
  • Power: 9VAC External Transformer, UL and CSA Approved
  • Dimensions: (WxHxD) 19"x1.75"x6" (483mm x 45mm x 153mm)
  • Weight: 4.5 lbs (2 kg)

How the QSR Generates Sounds

The architecture of the QSR can be confusing. Alesis created a powerful synthesis platform with lots of flexibility but the architecture is rather complex. If you are unfamiliar with the QSR, you will need to understand certain concepts and terminology. You must clearly understand Programs, Mixes, and Effects. I briefly mention those concepts here but additional information can be found throughout this Manual.

Programs contain the settings that determine how the QSR responds to incoming MIDI Note On commands. The QSR generates sounds from sample files. It combines up to four samples to create the sound for each note within a Program. The QSR supports high sampling rates on each sample file so there is no loss of sound quality. The availability of four sample layers is very powerful; layering can be used in several ways. You can layer individual sounds to change the character of the drum. Or you can use the velocity crossfading feature to change the sample based on the note's velocity. You can also use the layers to create a stereo sound from two mono sample files.

How Sounds Are Used

Sounds are defined within Programs that specify which sample files are used in each layer and how the layers are used. Once you have created programs, you can play them directly in the Program play mode. But there is another mode that is more powerful, called the Mix play mode. We will use Mix play mode with our custom Programs, as explained in this Manual.

Using Mix play mode provides more flexibility. Using Mixes, different QSR Programs can be played on each MIDI channel. You can assign Programs to each of the 16 Mix channels and set several of the Program parameters locally within the Mix. This allows you to use different Programs for each drum or combine Program sounds to create interesting effects.

The QSR is a polyphonic synthesizer. Polyphonic synthesizers output multiple sounds simultaneously so you can generate multiple instruments at once or layer sounds to change the character of an instrument. The QSR can simultaneously output 64 samples (or voices), which sounds like a lot. But you can still run into the 64-sample limit. The layering features of the QSR are well-suited for use as a drum synthesizer. But to avoid hitting the sample (voice) limit, Programs and Mixes must be carefully planned in advance.

Programming the QSR

The QSR is a powerful synthesizer. It has some great sounds that can be used out of the box. But to fully exploit the power of the QSR, you need to know what programming capabilities are available and how to use them.

The internal sounds of the QSR cannot be overwritten but you can upload custom samples to the QSR. There are Preset and General MIDI banks of Programs, Mixes, and Effects, which cannot be changed, but the QSR has a User bank that allows you to create custom Programs, Mixes, and Effects. You can copy Programs, Mixes, or Effects from Preset banks to the User bank and edit them from there. User bank data can be transferred over MIDI to a computer for backup and subsequent Flash RAM card programming. Alesis' Sound Bridge software makes the Flash RAM card programming easy.

The QSR front panel controls and LCD display allow navigation through a series of menus for selection and editing of programs. This process is very tedious, but fortunately graphical editors have been produced to make this process simpler. QS Edit Pro software is one such editor. It's operation will be described here.

Where do I learn more about the QSR?

The QSR Reference Manual is required reading for anyone using the QSR. It can be downloaded from the Related Information link below. The QSR Reference Manual covers many features, including some that do not apply in the context of building a drum synthesizer. The QSR Drum Synthesizer Manual supplements the QSR Reference Manual and focuses on concepts and procedures that are relevant to building a drum synthesizer using the QSR.