Kawai MS20 - personal keyboard small digital keyboard with built-in complex music patterns & impulsive rhythms

 This quite rare instrument seems to be the only halfway toy- like keyboard released by Kawai.

The sound is based on samples and is 4 note polyphonic (only 3 with accompaniment). It has 80 preset sounds and 16 preset rhythms. Every selected preset sound is introduced by a short jingle followed by applause. Like with the bigger Kawai MS720, the special feature of this instrument is an accompaniment mode that Kawai called "one finger ad-libtm". This feature simply automatically plays pre- programmed typical music patterns on the keys of the middle keyboard section (one pattern per key). The patterns correspond to the current rhythm style and play in the key of the current single finger chord so long their keyboard key is pressed. Unfortunately it has no fingered chord mode and behaves a bit stubborn, and also the patterns can not be mixed but only play one at a time. But although it was not designed for tekkno and has many restrictions, with some skill you can at least improvise in a Doop- like steamjazz style on this thing, and unlike the MS720 the MS20 has even quite impulsive percussion and the march drumrolls of the precisely hammering digital machine go really nice. There are also a few tekkno- like effect sounds on it and also outside tekkno it is generally quite fun and can be inspiring to play around with this virtual band.

main features:


  • AC- adapter jack polarity changed to standard
  • sound output jack + speaker mute switch added
  • keyboard matrix bug fixed (was polyphony mess with empty battery =>18 kOhm pullup resistors soldered from matrix inputs against +5V)
  • notes:

    The behaviour of this instrument has many similarities with the Casio SA series, although here the digital volume control doesn't reduce the bit resolution that badly. The control panel has soft touch foil buttons; the volume and tempo buttons play a beep which pitch indicates the current setting. When a preset sound or rhythm is selected with the ABCD- buttons, the instrument plays a short jingle with that sound (melody depending on the selected sound) followed by applause. Kawai calls this feature "self introduction". When preset sounds are stepped through with the "change" +/- buttons, each button press instead plays an example note with the selected sound. When the instrument is turned on, it starts with a monophonic tooting 4 note fanfare (with the "recorder" (flute) sound), and also when switched off it plays a 6 note jingle; their timbre resembles plain squarewave and were likely inspired by certain very similar tooting on/ off melodies on old toy laptops.

    Initially there was a polyphony bug that made note mess with empty batteries due to crosstalk on the keyboard matrix; solder from each key input an 18 kOhm pullup resistors against the +5V supply voltage of the IC LC7881 to fix this. (The 5V voltage there is controlled by the electronic power switch; using a voltage before the switch would empty the batteries through the resistors when not in use.) The power amp seems to be a bridge amplifier, but as usual also here a 100nF capacitor from the speaker "+" pin to the output jack works well. Strange is that the Kawai TC531000CP chip (ROM?) has 28 pins while on the PCB are 4 additional holes to support here also a 32 pin IC.

    The main voice preset sounds are made from 2 mixed medium resolution samples. While most sounds have only a simple (ADSR?) envelopes, the effect sounds use complex algorithmic envelopes, but unfortunately all but 1 play the same note on all keys. The main voice sounds are much cleaner but less complex than on Casio SA-1; especially they contain neither reverb nor echo effects. Unlike the bigger Kawai MS720 most employ simple waveform samples, and the bright ones sound harsh although not rough (possibly by a hissy speaker or amp). Most sounds resemble simple 2 operator FM timbres, but regarding the limitations of static waveform samples, most timbres are fairly realistic. In the following I will only describe unusual or unnatural sounding presets, and when not otherwise mentioned they employ waveform samples. The "pan flute" sample (selected after power- on) starts with a hissing wind (breath) noise; it is the only sound that starts this way. "flute" has vibrato. Most other wind instruments have a percussive attack phase (like an old, envelope- less electronic organ). "trumpet 1" sounds realistic, while 2 has a slow attack rate and rather resembles a harsh violin ("violin" has additional vibrato). "trumpet duo" sounds static like a single trumpet; only its attack phase sounds like 2 trumpets. "toy trumpet" instead has a more noticeable chorus, a quite percussive attack and sounds duller than "trumpet 1". "fat brass" 1 is a thinner(!) sounding synth brass chorus that resembles the famous Casio SA-1 "brass ens" (but thin like its "trumpet") while 2 has a slow attack phase and thus resembles a harsh violin ensemble ("strings" is similar with sustain). The pianos are made from static waveform samples without chorus and thus unrealistic. "piano" 2 is slightly duller than 1, "honky tonk" has detuned chorus. "e. piano" 1 resembles a Rhodes piano, 2 has additional chorus. "ef. piano" is another, quite dull piano with harsh bass range by low sample resolution. Both harpsichords sound of banjo. "jazz organ" is a clean Hammond organ sound, "drawbar 1" another one, 2 is harsher. "rock organ" is a creakier timbre with vibrato. "vib organ" 1 & 2 resemble "drawbar" with vibrato. "x fade" is a brighter fading metal pipe organ (like a Casio Consonant Vowel timbre). The strings sound quite cold; the bass range of "cello" could be also a harsh horn timbre. "koto" has vibrato. "glass solo" is a tooting glassy organ timbre with percussive attack phase (could be also a harsh telephone tone). "sequence" is simply a harsh, low and buzzy picked string (like a mandolin); "hard clavi" and "tine clavi" sound similar but with longer sustain phase. "rock clavi" has additional vibrato. "tubular bell" has chorus and the timbre resembles more a hollow picked string (banjo?). "orient bell" is quite harsh (like a My Music Center sound), "tine bell" is bright and very percussive, "small bell" even brighter. "glass harp" is a bowed glass. "wine glass" resembles a musicbox with additional strong vibrato. "cosmic" 1 resembles a harsh metallic e-piano with sustain, 2 has a slow attack rate and resembles a bowed glass and fades silent, 3 is like 2 with strong vibrato (or a glassy violin). "a. guitar 2" is like 1 with chorus. "guitar duo" doesn't sound like 2 separate guitars but more like an e-bass (on FM synth?). "vib guitar" is an acoustic guitar with vibrato. "e. guitar" is harsh and somewhat sitar- like (dry bass range). Also "funky bass" is harsh and percussive with buzzy, creaky bass range. "xylophone" is a bit harp- like. "glocken" is glockenspiel. "gamelan" more a vibraphone without vibrato (unlike Casio SA-1 without disharmonic overtones nor special tone scale). "steel drum" has a too soft bass range (rather an e-bass). "soft mallet" & "hard mallet" are also xylophones.

    The effect sounds except "invader" only play the same note on all keys, but you can make a phasing effect by pressing multiple keys. "car" is a car horn, "alarm" a high toot with fast purring tremolo (like a phone toot?), "police" alternatingly switches with 2Hz between a brassy tooting tone and a semitone higher. "gun" is a squarewave based historical videogame sound effect that goes "doenng!" in a buzzy way (like a  POKEY shift register noise effect). "invader" is a fast up and down bubbling, siren- like pattern that is melodically playable although it sounds not very melodic. "telephone" is a digital phone ring sound (2 fast alternating tones). Applause is what the name suggests (or frying eggs?) and fades silent. (But for tekkno effect sounds a Casio SA-35 is more interesting.)

    The "drum set" preset is a drum kit mode with 15 acoustic percussion sounds: {base, rimshot, snare, closed cymbal, high snare, hihat, low tom, mid tom, low conga, high tom, high conga, crash cymbal, tambourin?, gong}, those repeat in the same order on higher keys (play 2x same sound for phasing). The congas sound a bit electronic and the gong is likely the down pitched "crash cymbal" sample. (I have no manual and only named the sounds by ear.) Unlike Kawai MS720 the percussions don't sound dull but are quite bright, clear and impulsive sounding medium quality samples.

    The accompaniment (started with "auto" button) has unfortunately only single finger chord mode and thus only accepts a few standard chords. The accompaniment styles are complex orchestrated and always use an individual intro and ending; every 8th patterns they automatically insert a fill-in, which can be also confusing. (The Kawai MS720 had a manual fill-in button instead and rhythm could be started and stopped without intro/ ending.) With rhythm off, the accompaniment section plays a manual chord, which timbre depends on the selected rhythm. When the "one finger ad-lib" button is pressed, the keys in the middle keyboard section play each a looped music pattern. The music style depends on the selected rhythm. When accompaniment is started, it automatically plays a pre- programmed chord sequence in this mode until the player plays own single finger chords; with accompaniment the one finger ad-lib pattern plays always in the key of the current accompaniment chord. Each pattern starts as soon its key is pressed and stops as soon it is released. Unlike a groovebox it unfortunately does not sync by itself to the rhythm and they also can not be combined to play multiple tracks simultaneously. Although this thing was clearly not designed for tekkno, it makes still fun to abuse e.g. the "march" and "polka" rhythms in this mode to play in a Doop- like electronic steamjazz style. Unfortunately there are no separate volume controls for the individual tracks, and unlike Kawai MS720 the one finger ad-lib always starts the rhythm and can not be used without. The patterns each select its own main voice sound unless the player selects his own (switch one finger ad-lib off and on again to return to automatic selection). In the rightmost keyboard section the player can still play manually (with the preset sound selected by the pattern when no manual sound selected), although it is less than an octave and thus of little use.

    The demo is a complex orchestrated medley:

    1. happy pop/ latin fusion track (late 1980th style?)
    2. slow latin fusion tune (both resemble music from the Sega arcade videogame "Outrun")
    3. happy march with steel drums
    4. same theme continued in a jazzy swing (skiffle?) style
    Kawai apparently released only few different midsize keyboards and the MS20 seems to be the only really small (toy- like) keyboard by them. In the same series a very rare 49 midsize keys keyboard with "one finger ad-lib" (even 100 preset accompaniments with each 17 patterns) was released as Kawai MS50. A more professional midsize keyboard with MIDI and simple synthesizer was the Kawai MS720.
     removal of these screws voids warranty...    
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