Alesis S4 / S4 Plus

Alesis S4 Image

The QuadraSynth was introduced in 1993 by Alesis, and it was their first major synthesizer. The S4 is the rack-mount version of the QuadraSynth. It's a 64-voice digital synthesizer with a whopping 16 MB of sample ROM, and was the first synth to offer the ADAT Optical Digital interface. It also featured the same multi-effects processor as the QuadraVerb 2, drum kits based on the D4 drum module, 4 assignable control knobs, one PCMCIA card slot, 48kHz clock input, and 4 audio outputs.

The S4 is undoubtedly a powerful and flexible synthesizer capable of creating rich sounds - both acoustic and electronic. It uses digital additive/subtractive sample playback synthesis to create high quality stereo grand pianos, organs, strings, drums/percussion, brass, woodwinds, new and classic synth textures, and more.

Released in 1995/1996 came the new and improved S4 Plus version (pictured). The S4 Plus rack module came with only 20MB ROM, losing the coveted 8MB stereo Grand Piano sample found in the QuadraSynths in favor of 4MB of General MIDI pianos. For an all around versatile modern synthesizer module that isn't focused just on dance or trance, be sure to consider the S4 or S4 Plus.

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16 Visitor comments
January 18, 2011 @ 12:59 pm
I'll have to agree with planetplayer, above. As a user of both the S4 and the S4+ i have to say that the S4 sound much "cleaner" than it's big-brother, the plus model. Of course, having the possibility to use soundbridge and burn your own cards on the + is an advantage. Still, if i had to choose between them, i would take the S4 every day.
January 1, 2010 @ 10:39 pm
Nice sounding unit! The screen is large and gives tons of info for editing the patches. The 4 parameter control knobs are much nicer to use the buttons on some other units. The pianos, organs, strings and pads all very deep and rich sounding. I have several synths and if this one broke, I'd definitely replace it! I scored mine on ebay for about $150 - well worth it! Very easy to navigate, The unit has 4 preset banks of 128 each (bank 4 is a GM bank) and 1 User bank of 128. Lots of effects and flexibility - If one is available and in your budget, don't pass it by!
March 19, 2009 @ 10:40 am
I was lucky to get one of these S4 Plus together with the Grand Piano Q card. Ahhh, so warm. Some of the synth sound are nice. It's a portable piece that works with any midi controller keyboard. I use it as a dedicated Grand Piano sound in multi-track sequencing.
January 20, 2009 @ 2:52 pm
Yes, this did have a filter for it to be subtractive. For American standards the EMU filters sounded much much much better on their samplers then the Alesis Quadrasynth series. The Roland D-70 has a better filter also. However, like I mentioned and I think it's because of system design. The collection of single cycle synth waveform types and the filter together makes an impressive system and sounds real vintage. They don't sound like samples. It takes a very experienced professional ear to say it wasn't the real thing. Like EMU samplers of time. It can sound heavy weight analogue modular. Response time on S4 is quick too, midi trigger in to sound ouput.
January 20, 2009 @ 2:39 pm
Don't remember about filtering on this if any, but collection of vintage analogue samples sounds and new digital synth sounds are terrific. Acoustic Piano on orginal S4 is great. S4 Plus is to General Midi and I found it not for my use. These are hard to edit without computer. Like the S4 much better than the S4 Plus. S4 Plus did give option of adding user sampled burned sounds on PCMCIA Card. Both alowed PCMCIA factory card expansion. FX are great. Works well with ADAT system, other digital and anaolgue systems fine. Effects are clean, but very, very , very, very primitive. The D-50 reverb and chorus sounds better than S4 and S4 Plus. Good collection of Vintage synth wave samples. Good American sound and quality. Sorry that the company went to different hands they had excellent products. The S4 I love the most. The S4 plus I love the least. Everyhting else like QSR is lower than S4 and greater than S4 Plus.
VSE Rating

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User Rating

Rated 3.4 (146 Votes)

  • Check Price
  • The link above will take you to an eBay search for this synth to see active listings. If you don't find it there, try looking in our forum marketplace or post a wanted classified.
  • Demos & Media
  • YouTube Thumbnail
    S4 Plus Factory Demo.
    by eonporter1

    Manual - Alesis have made manuals and program charts for many of their products available on-line, for free download as .PDF files.

  • Specifications
  • Polyphony - 64 voices
  • Oscillators - 48kHz Linear samples
    S4: 16MB, expandable to 24MB using PCMCIA ROM and RAM cards
    S4 Plus: 20MB, expandable to 28MB using PCMCIA ROM and RAM cards
  • Multitimbral - 16 parts
  • Effects - 4 On-board effects, based on the Alesis QuadraVerb 2 FX processor
  • Arpeg/Seq - None
  • Keyboard - None
  • Memory - S4: 128 preset 128 user programs, 100 preset, 100 user mixes
    S4 Plus: 512 preset 128 user programs, 400 preset, 100 user mixes
  • Control - MIDI IN/OUT/THRU (16-channels)
  • Date Produced - 1993 (S4)
    1995 (S4 Plus)
  • Resources & Credits
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