Released in 1985, few could have predicted it would become a studio and live sound classic. Even Yamaha, who continued to release improved models year after year, likely did not foresee the enduring legacy of the Yamaha SPX90. Despite later iterations boasting improved noise floors, wider bandwidth, and stereo inputs, the original Yamaha SPX90 remains the most sought-after effects processor from Yamaha’s lineup.
The Yamaha SPX90 quickly established itself as one of the most versatile and musically useful rack-mounted digital effects processors of its era, combining affordability, ease of use, and a rich selection of high-quality effects. Drawing on Yamaha’s extensive experience in audio technology and manufacturing, the Yamaha SPX90 delivered 30 ROM-based preset effects, each with up to nine controllable parameters, and the ability to store up to 60 user-programmed effects in RAM for instant recall.
Its broad range of algorithms included full, natural-sounding reverbs, Early Reflection patterns, delay and echo programs, modulation effects such as chorus, flange, tremolo, vibrato, symphonic, stereo phasing, and advanced special effects like Freeze, Pitch Change, Auto Pan, and Gate Reverb. It also incorporated a fully digital parametric equaliser for precise tonal shaping.
The Yamaha SPX90’s reverb algorithms, including Hall, Room, and Plate types, were renowned for their clarity and vibrancy, while the Early Reflection settings provided tight, slapback-style ambience ideal for percussion and vocal enhancement. Delay and echo programs featured independently variable left and right channel times for doubled or spacious stereo effects. Modulation options like stereo flange, chorus, tremolo, and symphonic thickened the sound of instruments, while vibrato added a distinctive vocal-like character.
Freeze mode allowed up to 500 milliseconds of sampled sound to be recorded and replayed, with pitch and loop points adjustable in real time, including via MIDI. Pitch Change provided fine control in 0.1 semitone increments over a ±1 octave range, with optional feedback for harmonisation effects. Gate and reverse reverb programs, ADR noise gate, and compression functions further expanded its sound design potential.
Front panel operation was made simple by a large, high-contrast LCD displaying program names and parameter values, alongside a numeric LED display for memory locations and a 7-point LED input level meter. Dedicated controls allowed quick parameter adjustment, balance between direct and effected sound, memory storage, and recall. The Yamaha SPX90 supported MIDI program change and parameter control, enabling seamless integration into performance setups, and effects like Freeze and Gate Reverb could be triggered via MIDI or a footswitch.
Connectivity was comprehensive for its time, with unbalanced ¼-inch phone jacks for input and stereo outputs, a MIDI In and Thru, and a rear-panel output level selector for matching to source or line-level equipment. The optional RC7 remote controller provided direct access to preset and user memory locations.
Applications ranged from live sound reinforcement to studio use, with Yamaha illustrating setups for MIDI keyboard rigs, electric guitar systems, dual-unit PA configurations, and multitrack home recording. Its 31.25 kHz, 16-bit linear A/D and D/A conversion and 20 Hz–12 kHz bandwidth for processed signals were competitive in 1985, while its direct bypass mode offered 20 Hz–20 kHz for unaffected audio. The Yamaha SPX90’s dynamic range exceeded 75 dB for reverb and 81 dB for delay programs, with distortion levels under 0.03% for processed sound.
Compact at 480 mm x 45.2 mm x 285 mm and weighing 3.2 kg, the Yamaha SPX90 was both portable and rugged, making it ideal for touring rigs as well as permanent studio installations. Its combination of professional-grade sound quality, user-friendly interface, and extensive effect library cemented its place as one of the most iconic digital effects processors in recording and live sound history.
Features
- 30 factory preset effects: reverb, early reflections, delay, echo, modulation, pitch change, gating, compression, parametric EQ
- Up to 9 controllable parameters per program for detailed effect editing
- 60 user memory locations for storing personalised effects with custom titles
- Full MIDI implementation for program change and parameter control
- High-quality reverb algorithms including Hall, Room, and Plate types
- Early Reflection patterns for realistic ambience and slapback effects
- Independently variable left/right delays for spacious stereo effects
- Modulation effects such as chorus, stereo flange, symphonic, tremolo, and vibrato
- Freeze function allowing up to 500 ms sample capture with pitch and loop point editing
- Pitch change with fine resolution adjustment over a ±1 octave range
- Gate and reverse reverb programs for creative sound shaping
- ADR noise gate and compression for dynamics control
- Fully digital parametric EQ with adjustable frequency, bandwidth, and gain
- Large, high-contrast LCD for program names and parameter data
- 7-point LED input level meter for precise signal monitoring
- Direct/effect balance control for blending processed and dry signals
- MIDI and footswitch triggering for Freeze and Gate Reverb effects
- Unbalanced ¼-inch phone jack input and stereo outputs
- Output level selector for source or line level matching
- Optional RC7 remote controller for direct memory access
- Compact, rackmountable design with lightweight, roadworthy build
4 Responses
Mike Stern in a nutshell.
I have a question about the sound samples:
the dry drums (for example) are stereo and the wet reverb samples are also stereo.
how did you do that with a mono input? two units for left and right maybe?
It was a simple mono send of the snare to the Yamaha, and the stereo return.
In cubase, I send a mono drum track to the spx and the sound is immediately skewed to one side, causing a severe imbalance between left and right. I have connected the L and R of the spx to the two inputs of the audio interface respectively.
Can the master tell me what to do?
Thank you.