The Alesis SR-16 is a compact, powerful drum machine that defies its diminutive size with an impressive array of features and sounds. Measuring just 9" × 6.5" × 1-1.75" and weighing a mere 1.5 pounds, this laptop-sized beatbox delivers professional-grade performance in a highly portable package.

Sound Library

The SR-16's standout feature is its extraordinary onboard sound library of 233 high-quality 16-bit drum and percussion samples—an exceptionally generous complement that eliminates the need for expansion cards. The sound distribution reflects a clear focus on versatility for modern music production:

• 49 kick drums covering acoustic and electronic styles, from tight punchy sounds to ambient reverberant kicks, including the classic 808 kick
• 59 snare drums ranging from dry acoustic snares to heavily processed electronic variations, including the iconic 808 snare
• 51 tom drums (hi, mid, and lo versions) spanning deep booming acoustic toms to hard, tight electronic sounds
• 19 hi-hat samples with excellent top-end clarity and detail
• 12 cymbal sounds (ride and crash) varying from harsh to delicate
• 42 percussion instruments including tambourine, shaker, congas (with slapped variations), timbales, agogos, claves, woodblocks, cowbells (including three differently-pitched 808 cowbell versions), fingersnaps, claps, cabasa, and special sounds like Impact and Sample & Hold

Notably, 94 of the 233 sounds are stereo samples, with approximately half the kicks, snares, and toms, plus select hi-hats and percussion rendered in stereo. The library features a balanced mixture of dry and reverbed sounds, with many stereo samples also being reverbed versions.

Advanced Features

The SR-16 introduces "advanced dynamic articulation techniques" that reproduce the varying timbral response of acoustic drums when struck with different force levels. This creates realistic responsiveness on select kicks, snares, congas, and toms when using velocity-sensitive performance.

A unique innovation is the Sample & Hold feature—a software-implemented special effect that randomly plays one of four sounds (two tunings of 808 cowbell, woodblock, and agogo bell) with each pad hit. This creates constantly-changing cross-rhythms, ensuring patterns never sound exactly the same twice. When assigned to multiple pads with different rhythms, tuning, and panning, it generates complex random textures ideal for electronic music.

The samples themselves are well-detailed, dynamic, upfront and punchy with plenty of presence—characteristics that make the SR-16 particularly well-suited for modern dance rhythms and contemporary music production.

Pattern Programming

The SR-16 offers exceptional flexibility in pattern creation and performance:

Pattern Structure:

• 50 factory Preset Patterns covering rock, hard rock, R&B, funk, blues, rap, techno, reggae, jazz rock, fusion, new age, country, jazz, Latin, and ballad styles
• 50 User-programmable Patterns, each consisting of four sub-patterns: Main A, Main B, Fill A, and Fill B
• This A/B/Fill architecture effectively provides 200 user patterns (50 × 4)
• Patterns can be up to 128 beats long (32 bars in 4/4 time)

Recording Options:

• Real-time recording with loop capability
• Step-time recording with bidirectional navigation
• Maximum resolution of 96 pulses per quarter note (ppqn)
• Quantization available from quarter notes to 64th notes during recording
• Swing settings at 54%, 58%, or 62% for jazz, go-go, and swingbeat feels
• Quick-repeat function: hold pad + Fill button for rapid note entry at current quantization value

Performance Features:

• Seamless switching between Perform and Compose modes during playback
• Fill patterns can be triggered from any position except the first step
• Intelligent Fill behavior: releasing Fill button before pattern end transitions to alternate pattern (A to B or B to A); holding through pattern end returns to same pattern
• Pattern parts can be shifted forward or backward in time up to 99 steps (at 96ppqn resolution)
• Individual drum parts can be independently edited, copied, merged, and erased

The SR-16 can typically store over 15,000 events, with memory capacity varying based on pattern complexity—ranging from a minimum of 96 to approximately 136 patterns filled with identical 192-hit rhythms.

Drum Sets

The organizational structure centers on Drum Sets — collections of sound assignments for the 12 playing pads:

• 50 Preset Drum Sets
• 50 User-programmable Drum Sets
• Each Main pattern can be assigned any Drum Set
• Per-pad parameters include: volume (0-99), stereo position (L3-center-R3), tuning (+3/-4), triggering mode (single, multi, group 1, group 2), and output assignment (Main or Aux stereo outputs)

MIDI Implementation: A clever feature allows the SR-16 to function as a MIDI drum expander. By setting the Note Map parameter to D40-49, Drum Sets 40-49 can be played via MIDI with 120 sounds preassigned to consecutive MIDI notes 0-119, responding to all 127 MIDI volume levels. In this mode, the SR-16 simultaneously operates as both drum machine and keyboard-performable sound module.

Song Construction

The SR-16 offers two methods for creating complete song arrangements:

Manual Programming:

• Up to 100 songs
• Each song can contain up to 254 steps
• Each step can be a Main or Fill pattern
• Fill patterns can be precisely positioned to 96ppqn resolution
• Individual song steps can be added, inserted, replaced, deleted, and copied
• Each song has its own tempo (20-255 BPM), though no mid-song tempo changes are possible

Real-Time Recording: A standout feature is real-time Song recording—select an initial pattern, press Play, and the SR-16 automatically records all pattern selections as you perform them, compiling a song chain on the fly. This spontaneous approach is particularly effective for Fill selections and works when slaved to external sequencers or drum machines for interactive composition.

Performance Mode: During Song playback, holding the Count/A/B/Fill footswitch repeats the current pattern step indefinitely, allowing spontaneous extension for solos or improvisational sections.

User Interface

The SR-16 features a straightforward, intuitive interface with clearly marked modes and functions accessible via dedicated front-panel buttons. Twelve small rubber playing pads run across the lower section—comfortable for finger performance with proximity advantages. The pads offer limited velocity sensitivity with eight levels, which the SR-16 records whether from pad input or MIDI. Pad response can be weighted as Soft, Medium, or Loud, or set to one of eight fixed response levels.

One limitation: the LCD screen lacks backlighting, making it difficult to read in poor lighting conditions. However, the bottom panel conveniently displays a printed list of preset patterns and basic instructions that can't be lost.

Connectivity & Data Management

Audio Outputs:

• Main L/R stereo outputs
• Aux L/R stereo outputs (each pad can be independently routed to either output pair)

MIDI:

• MIDI In and Out/Thru sockets
• Global MIDI note assignments (0-127) per pad for both transmit and receive
• Patch change reception for remote Drum Set selection
• Receive channel selectable from 1-16 or Omni
• Synchronization as slave to external sequencers or drum machines in Pattern mode

Control Inputs:

• Start/Stop footswitch input
• Count/A/B/Fill footswitch input

Data Storage:

• Tape In/Out mini-jack for data backup/restore
• MIDI System Exclusive transfer to devices like Alesis DataDisk or another SR-16
• Save/load options: all data, individual patterns, individual songs, individual Drum Sets, or single drum pad parts

Power:

• 9V AC external adaptor (included)
• Power on/off button

Polyphony & Performance

The SR-16 provides 16-voice polyphony—generous for a drum machine and sufficient for layering multiple variations of the same rhythm using different kick or snare sounds assigned to separate pads. This capability is particularly effective for creating depth by combining tight and ambient versions of the same drum sound.

Verdict Summary

The SR-16 represents exceptional value at its £299 retail price, offering thoughtful implementation, user-friendly operation, innovative features, and a generous complement of quality sounds. Its particular strength lies in providing budget-conscious musicians access to an extensive kick, snare, and tom library typically available only with samplers, without requiring additional investment in expansion cards.

The machine excels at spontaneity through its A/B/Fill pattern selections, interactive programming, and real-time song chaining. The sound quality is distinctly modern, with samples well-suited to contemporary dance music and electronic production. While the heavy emphasis on kicks, snares, and toms means less variety in other percussion categories compared to some competitors, the sheer number and quality of core drum sounds sets it apart in the budget drum machine market.

Minor drawbacks include the non-backlit LCD display and a relatively narrow tuning range (+3/-4). The SR-16 cannot substitute for a sampler's flexibility, nor does the fixed sound complement match the expandability of card-based systems, but these limitations are offset by the immediate availability of such an extensive, high-quality sound library.

Technical Specifications

Physical Specifications

• Dimensions: 9" × 6.5" × 1-1.75"
• Weight: 1.5 lbs
• Form Factor: Laptop-sized, compact drum machine

Sound Engine

• Sound Library: 233 total sounds (16-bit samples)
  • 49 kick drums
  • 59 snare drums
  • 51 tom drums (hi, mid, lo versions)
  • 19 hi-hat samples
  • 12 cymbal sounds (ride and crash)
  • 42 percussion instruments
• Stereo Samples: 94 of 233 sounds
• Sound Types: Mix of dry and reverbed sounds; acoustic and electronic sounds
• Dynamic Articulation: Advanced dynamic articulation techniques on select sounds
• Sample Expansion: None (no ROM card slot)
• Polyphony: 16 voices

Performance Interface

• Playing Pads: 12 velocity-sensitive rubber pads
• Velocity Levels: 8 levels (recording and playback)
• Pad Response Settings: Soft, Medium, Loud weighting, or 8 fixed response levels
• Display: LCD (non-backlit)

Pattern Programming

• Preset Patterns: 50 (covering multiple musical styles)
• User Patterns: 50 (each with 4 sub-patterns: Main A, Main B, Fill A, Fill B)
• Effective User Patterns: 200 (50 × 4)
• Pattern Length: Up to 128 beats (32 bars of 4/4)
• Resolution: 96 ppqn (pulses per quarter note) maximum
• Quantization: Quarter note to 64th notes
• Swing Options: 54%, 58%, 62%
• Time Signature: Not user-definable (metronome accent on first beat only)
• Pattern Memory: Typically over 15,000 events (varies by pattern complexity)
• Recording Modes: Real-time loop recording, step-time recording
• Pattern Editing: Time-shift (±99 steps), copy, append, double, merge, erase

Drum Set Organization

• Preset Drum Sets: 50
• User Drum Sets: 50
• Pad Parameters per Set:
  • Volume: 0-99
  • Pan Position: L3-Center-R3 (7 positions)
  • Tuning: +3/-4 semitones
  • Triggering Mode: Single, Multi, Group 1, Group 2
  • Output Assignment: Main or Aux stereo outputs

Song Mode

• Total Songs: 100
• Steps per Song: Up to 254
• Step Types: Main or Fill patterns
• Fill Positioning: 96ppqn resolution
• Tempo Range: 20-255 BPM (per song, no mid-song tempo changes)
• Song Recording: Manual step entry or real-time recording
• Song Editing: Add, insert, replace, delete, copy, append steps

Audio Connections

• Main Outputs: L/R stereo (1/4" jacks assumed from era)
• Auxiliary Outputs: L/R stereo
• Output Routing: Per-pad assignment to Main or Aux outputs

MIDI Specifications

• MIDI In: Yes
• MIDI Out/Thru: Combined socket
• MIDI Channels: 1-16 or Omni (receive)
• Note Range: 0-127 (per-pad assignment, global)
• Patch Change Reception: Yes (for Drum Set selection)
• System Exclusive: Full implementation for data transfer
• MIDI Expander Mode: Note Map D40-49 (120 sounds on consecutive notes 0-119)
• MIDI Velocity Response: All 127 levels in expander mode; 8 levels in normal mode
• MIDI Sync: Slave to external clock in Pattern mode

Control Inputs

• Start/Stop: Footswitch input (1/4" jack)
• Count/A/B/Fill: Footswitch input (1/4" jack)

Data Storage

• Tape Interface: In/Out mini-jack (data only, not audio)
• SysEx Storage: Via MIDI to external devices
• Save/Load Options:
  • All data
  • Individual Pattern
  • Individual Song
  • Individual Drum Set
  • Single drum pad part from Pattern
• Verify Function: Yes

Power

• Power Input: 9V AC
• Power Supply: External AC adaptor (included)
• Power Switch: Rear panel on/off button

Special Features

• Sample & Hold Effect: Random selection of 4 sounds per pad hit
• A/B/Fill Architecture: Four patterns per preset/user pattern slot
• Real-time Song Recording: Automatic song chain compilation during performance
• Interactive Programming: Switch between Perform/Compose modes during playback
• On-the-fly Editing: Edit pad assignments and parameters while running
• Pattern Song Hold: Hold current pattern indefinitely via footswitch during song playback
• Quick Repeat Entry: Hold pad + Fill button for rapid note entry

Documentation

• Manual: Included (described as friendly, helpful, concise, clear)
• Quick Reference: Printed on bottom panel (preset patterns list, basic instructions)