The Casio HT700 is a small keyed non-touch sensitive stereo DCO[Digitally Controlled Oscilator] (PCM[Pulse Code Modulation]) keyboard.
The DCO system has 31 waves to create the sound. This is not Phase Distortion or FM or sampling and is akin to the analogue sound from the old oscillator days,except the waveshapes are more complex than square and triangle - in some cases varying over time.
The HT700 (and similar models) uses a digital filter with ADSR envelope to shape the tone of the DCO selection - the filter is very efficient and can almost blank out the sound completely when the frequency of the filter is low. This means that those sweeping sounds or "WOW" type wah effects are easy to generate - but on the whole the capacity to mimic conventional instruments is poor.
The 700 has a pitch bender which as with most Casio models is fixed at high resolution altering of a couple of semitones. You can add a RAM card [RA100] to enhance the storage capacity - but these are hard to get hold of and not cheap. You get up to 60 tones with the RAM card or 20 ROM and 20 RAM without it. There is a mini mixer which operates via sliders controlling the main volume,the accompaniment and the drums - which is a useful discrimination.
The output sound is emitted from a small stereo jack for headphones and two phono sockets for LINE out. The unit can be tuned manually from a preset on the rear of the unit and runs off 9v. A sustain jack is provided and MIDI IN and OUT - no THRU.
One of the more useful features of the HT-700 is the data entry wheel - which makes editing of the DCO parameters quite quick.The LCD display has no backlight though,so maybe illegible under low light levels.
The 700 has a rather crude memory system for storing patterns and drum riffs and can operate on 3 successive MIDI channels - the first being the main voice,the second being the accompaniment voice and the third being the bass line.
There is a programmable LFO for vibrato effects and ADSR for the volume - the accompaniment tone can also be edited and has it's own set of parameters - so really you have two DCO tones at your disposal on two MIDI channels.The Bass is not editable.
There are only about 9 drum sounds which is pretty limited by today's standards and they are not up to the same standard as modern keyboards - but they are passable - although the whole effect of the HT-700 sounds a bit "toy" - even so - there is a Chorus unit which can be set to multiple settings and this helps add some life to the sound.It is also possible to feed the MIDI out to MIDI in without looping (as Yamaha's may do.PSS series use the OUT as a THRU) - this means that there is a slight delay as the unit picks up the MIDI note that it generated itself.So both the note it generated locally and the one it has received both sound - creating a phasing effect.
Editing the tones is a complex affair, as is storing and editing patterns in the chord memory and there is no SYSx dumping system,so you are reduced to writing the numbers down on paper - Casio have thoughtfully provided a data sheet in the manual - which is also downloadable from [templarseries.atspace.com/c-data.html].
In each of the patterns for drum and chord you can even program the fill - but this is tricky unless you are a bit of a virtuoso,but the timing of the patterns and chords is quantized so you can't really end up making a mess.
The drum machine can be synchronised to an external sync pulse - so this is not one of your channel 10 compliant machines.It does not generate drum notes as do most Yamaha's - but the sync pulse arrangement is good and it is relatvely easy to get it to sync to most anything.
The whole unit is transposable 5 or so tones either side of centre.
Overall it is quite an impressive little beast for it's size and well worth a look in if you find one on Ebay - it's bigger cousin's add features such as modulation wheels and more storage space - but if you want to check out a sound production method other than PD,FM,sampling then this is a relatively cheap introduction to (Pulse Code Modulation) DCO's - it's hardy a full featured keyboard,but lacks little in the way of charm - one becomes fond of it rather like a trusty VIC20 or a MINI.
Soundclips of this device in use can be found at [templarseries.atspace.com/sounds.html]
Similar models are the HT3000 which is basically a big keys version. The HZ600 which lacks the rhythm unit and the HT6000 which does not have one filter for the whole sound but separately triggered filters.
The 3000 is very much a full size version of the 700 and only seems to add separate control of the sound of the accompaniment,a modulation wheel and a MIDI thru.
I believe the HZ-600 is a 3000 without the drum machine facilities.
Good Points: The inclusion of a pitch bender is never sniffed at.The data entry wheel is an asset. Inclusion of phono outputs for LINE out means you can connect to a mixer or PC easily without using the headphone socket. The rhythm programmer is easy to control and thus you have a basic programmable drum machine t'boot.
Niggles: The lack of connection to an external storage device is all I can think of at the moment - however,the DCO uses relatively few parameters,so it is no great bug bear to write them down - it as well though to either keep the unit plugged in or have some batteries inside - that way it does not lose what you have programmed - otherwise you are stuck with typing in all the parameters again!