Bontempi KS 4600 (bad sounding wannabe sound bank keyboard with lo-fi percussion)

This noisy digital tablehooter would certainly rank on one of the higher places in a "worst keyboard of the world" contest, because despite this initially 199DM (about 100€) expensive wannabe sound bank thing had 160(!) fancy named preset sounds, they all sound similar and are made from only few static digital waveforms (each 2 mixed sine waves?) with very few and primitive volume envelopes.

All sounds are infested with strong digital aliasing noise and have audible zipper noise. In unmodified state this thing yells ear tormentingly loud out of its hollow roaring speaker unless you turn volume lower, but this makes the sound even worse because the digital volume control steals bits from the low resolution DAC. The percussion is made from low- res samples and sound quite bassy; especially the tom drum distorts extremely and the cymbal decay phase drowns in aliasing noise.

main features:




The user interface of this tablehooter is a bit awkward; the volume control  it has no volume control buttons but the tempo +/- buttons serve this purpose when pressed while holding the "sound/ master vol." button (which normally switches cipher buttons to sound select mode). For rhythm/ accompaniment volume control hold down "rhythm/ acc. vol." instead (switches normally cipher buttons to rhythm select). Strange is that the latter does not control the bass volume of the accompaniments. Theoretically these 2 buttons could have been omitted anyway, because by the count of entered digits the hardware should recognize whether a sound or rhythm number is entered. 

The PCB has trimmers for tuning and volume preset. You can add here a real volume potentiometer or at least turn down the preset volume (very recommended), because the given volume control badly reduces the (anyway low) bit resolution of the sound. With internally adjusted volume the sound turns at least bearable. Bizarre is that the separate ROM(?) IC was covered with a white paper sticker "3220 9901", and its real label underneath contains the word "ALDI", which is a big German supermarket chain that over the years sold multiple Bontempi keyboards models in custom printed package boxes. (My KS 4600 box and case has no hints to ALDI on it.)

Despite the 160 main voice preset sounds include multiple variants of exciting names like "xylo spring", "analog", "fx piano", "cosmic", "fantasy", "fant. piano", "cosmic piano", "synth spinet", "space", "peak", "metal guitar", "odyssey" etc., they are all made from each a static digital waveform (Hammond- like timbres, possibly 2 mixed sine waves) combined with one of only few different attack- decay envelopes, thus most presets sound not remotely natural. It is not worth the effort to explain them in detail here, because at first hear they all simply resemble either cheap tooting analogue home organ tones or Rhodes piano sounds (with different decay rates), but unlike these they contain much digital aliasing noise. The preset sounds contain neither vibrato nor tremolo nor any pitch changes (not to say complex stuff like ringing mandolins) and with sustain off all notes stop immediately after releasing a key. I guess they employ only about 5 different  envelopes {envelope- less toot, toot with slower attack rate, 3 differently fast decay envelopes}. I consider this almost a fraud, because the sounds are way too similar to deserve 160 differently named ones (the individual sounds of an MC-3 differ more). Instead of this annoying pseudo- sound- bank Bontempi better should have added 4 synth buttons (envelope +/- and timbre +/- like the "voice variator" on Yamaha PSS-80) to combine every waveform with every envelope in an easy and logical usable way, but apparently Bontempi attempted to visually compete by raw force with Casio and Yamaha instruments although they had no technical means to do so. And by the too high preset volume the blatant sound flaws get even more obvious, because the thing always comes up at maximum volume after power- on, which makes the small speaker distort unless the digital volume control is set so low that the this way reduced bit resolution ruins the sound quality instead. Likely this was intended to yell together all shopping center customers to make them quickly turn their head and look for the sudden noise source, but I severely doubt that when found this made them in any way interested in buying one of these tablehooters - not to forget that it certainly made the shop staff as quickly decide to remove all batteries and power supply from such a roaring beast in the display shelf to make it stay quiet for the rest of the season until it collects dust. The peak of impudence is that Bontempi advertised this yelling beast on the box with the feature "high fidelity speaker for the best sound"; in the German language version instead it is called "Hochleistungs- Lautsprecher" (in English "high- power speaker"), which is at least a less incorrect description.

The percussion is monophonic and made from low- res samples; especially the tom drum distorts extremely and the cymbal decay phase drowns in aliasing noise. The lo-fi drums sound quite fat and bassy and may be nice for tekkno. Annoying is that the tempo can be set not much lower than medium, although it can be otherwise set quite high.

The accompaniments of different rhythms contain different sounds and are nicely made. There is even an "intro/ fill-in" button for the rhythms. Without rhythm the accompaniment plays always the same organ chord timbre, that makes a quiet popping noise during chord changes. The finger combination to play a chord depends on "System 5 " knob setting. The mode "free chord II" is classic fingered chord mode; you even can play any non- chord key combinations, although with accompaniment plays monophonic with non- chords. Without rhythm the organ chords hold until releasing all keys in the accompaniment section. Like with Bontempi GT 509, you can assign chords to 6 rubber button pads. For this set the "System 5" knob to "easy chord program", "single finger" or "free chord I" and pressing "record". Then play a chord in the accompaniment section of the keyboard and simultaneously press the pad you want to assign it to. Press "record" again to finish. (Stored chords are erased by auto power- off.)

The demo music plays a very long medley of partly very short songs those employ standard accompaniments with monophonic main voice.

  1. The Old Folks at Home
  2. Song of Joy
  3. [funk]
  4. [funk]
  5. [funk]
  6. It's a Groovy Kind of Love
  7. ?
  8. [bigband]
  9. [boogie]
  10. American Farewell (?)
  11. Love Me Tender
  12. Auld Lang Syne
  13. Yankee Doodle
  14. When the Saints Go Marching In
  15. [march]
  16. La Paloma [long and nice]
  17. [known country song]
  18. [fast latin music]
  19. Lambada (sort-of)
  20. [rock organ]
Bontempi released a lot of other keyboard variants with the same case design like the KS 4600, those have different count of preset sounds, different controls and possibly a different sound generator. E.g. there are Bontempi KS 3400 (32 keys, no drumpads), KS 4400 (40 keys, no drumpads, 96 sounds, 16 rhythms, "arranger" (= sequencer?)). Apparently the successor series (blue pads and writing) were Bontempi AT 606 (32 keys, 60 sounds, 30 rhythms, buttons instead of knob, no drumpads), AT 707 (40 keys, 60 sounds, 30 rhythms, 30 "arrangements" (= accompaniments?), drumpads left next to the speaker), Bontempi BT 704 (40 keys, 24 sounds, 24 rhythms 6 combined drum/ chord pads), BT 704/S (40 keys, 36 sounds, 24 rhythms). Later variants (with green panel stuff: Bontempi - Kids Music KT 32 (32 keys), KM 40 (40 keys) | with blue panel stuff: BT 605 (32 keys), BT 705 (40 keys)) were already based on the 666 sounds hardware like Bontempi GT 509. A smaller and even worse sounding keyboard based on the same sound generator like KS 4600 is the Bontempi ES 3300.
 removal of these screws voids warranty...    
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