Back to Keyboards
Originally uploaded 15/02/2015. Last updated 20/07/2023
Introduction
The Casio HT-700 was a Spectrum Dynamic synthesiser released in 1987. Its price when new was roughly $399 (£239.18) and it often sells around £25 - £90 on the second hand market.
I paid around £80 in total for my HT-700 which was a little bit higher than I wanted, but it came in such good condition along with it’s original box.
The HT-700 is fairly rare in the second hand market place which some people say gives it a little bit more charm.
The HT-700 is fairly rare in the second hand market place which some people say gives it a little bit more charm.
Features
The Casio HT-700 features a total of 40 voices, 20 of which can be used to store custom and edited voices. It is possible to add an additional 20 voices by using the optional RAM Card.
The RAM card is quite rare in the second hand market place and because of this, when it does appear it is often very expensive. I’ve only seen one RAM card for sale on an online auction site and it sold for over £50.
The keyboard can play up to a maximum of 8 notes at a time (4 when the auto accompaniment system is on).
One of my favourite features of the keyboard is the fully programmable auto accompaniment system.
You can create your own drum patterns using the built in drum sequencer as well as programming your own bass patterns.
It is possible to program the chord pattern as well, but it is limited only to chord variations. The keyboard also quantises the patterns you program in which corrects any timing mistakes that might occur while creating the patterns. Accents can be added to the drums, bass and chords by pressing the accent key (<).
When the pattern is saved, it can be played just like the built in auto accompaniment styles.
The keyboard even transposes the patterns when you press the corresponding keys in the chord section.
This enables you to create new auto accompaniment styles to play along with instead of being stuck with the built in ones.
The RAM card is quite rare in the second hand market place and because of this, when it does appear it is often very expensive. I’ve only seen one RAM card for sale on an online auction site and it sold for over £50.
The keyboard can play up to a maximum of 8 notes at a time (4 when the auto accompaniment system is on).
One of my favourite features of the keyboard is the fully programmable auto accompaniment system.
You can create your own drum patterns using the built in drum sequencer as well as programming your own bass patterns.
It is possible to program the chord pattern as well, but it is limited only to chord variations. The keyboard also quantises the patterns you program in which corrects any timing mistakes that might occur while creating the patterns. Accents can be added to the drums, bass and chords by pressing the accent key (<).
When the pattern is saved, it can be played just like the built in auto accompaniment styles.
The keyboard even transposes the patterns when you press the corresponding keys in the chord section.
This enables you to create new auto accompaniment styles to play along with instead of being stuck with the built in ones.
The HT-700 features a pitch bend wheel, which can bend the note up to 2 semi-tones.
The pitch bend wheel can be used only with the main voices and the bend range cannot be changed. The non-programmable version of the HT-700 called the MT-600. This keyboard does not support editing voices but it used the same synthesis method to generate its sounds. |
Programming the Synthesizer
The keyboard features a single jog wheel and two buttons for programming the synth. When the synth is not in edit mode, the jog wheel acts as the tempo control for the built in drum sequencer.
The two buttons below the jog wheel are labelled ‘Mode’ and ‘Data’.
When the ‘Mode’ button is pressed, the keyboard is placed into ‘Edit’ mode and the LCD screen displays the parameter number. If the ‘Data’ button is pressed, the parameter settings can be edited, for example, if the user wanted to change the oscillator waveform, the user would press the ‘Mode’ button, move the jog wheel until it displays the number ‘00’ and then press the ‘Data’ button. When the waveform that the user wants has been selected, they simply press the ‘Mode’ button again and then edit the other parameters.
The jog wheel is in fact analogue. I was expecting the wheel to be digital like what you would find on some new car stereos. While I like the smooth feel of the jog wheel, being analogue can make it a bit of a nuisance at times, for example, if you changed the oscillator waveform to 31, which involves moving the jog wheel all the way to the end, and then wanted to transpose the keyboard, you would have to move the jog wheel back to find the correct parameter number.
When programming the keyboard, the manual is vital for knowing which number correspond to which parameter. The keyboard has a small table just above the LCD screen that briefly tells you which number corresponds to which parameter, however it lists them as groups e.g. 00 – 10 corresponds to the oscillator and LFO.
I think they changed this with the HT-6000 as they printed the full parameter list on the top of the keyboard.
I have created a PDF file which list which parameter corresponds to the numbers shown on the screen. You can download it for free here
The LCD screen has some indicators that tell you if you are editing the chord or main voice.
The keyboard has a total of 32 waveforms to choose from (the waveform settings start at 00). Some can sound warm and analogue while others can sound metallic and gritty. A few of the waveform’s timbre or textures can change over time, some of which can be controlled with the amplifier envelope. A good example of this is waveform number 9.
This gradual change in harmonics is what differentiates ‘Spectrum Dynamic Synthesis’ to the standard ‘Subtractive Synthesis’.
The HT-700 features two Low Frequency Oscillators (LFOs), which is fixed to modulating the pitch. The LFO for the main voice has 5 waveforms; Triangle, Descending Sawtooth, Ascending Sawtooth, Square and a Random waveform.
It is also possible to program the chord voice as well. Programming the chord voice is similar to programming the main voice although the chord section does not have as many features. The chord voice has only 16 waveforms instead of 32 and the LFOs waveform is fixed to a triangle wave.
The HT-700 lacks the lower tone buttons found on the other keyboards in the Spectrum Dynamic range, so the only way to save a chord voice is by pressing one of the auto accompaniment buttons.
The HT-700 does not feature a battery backup so all voices saved in the internal memory will be lost if the keyboard is disconnected from a power source.
While I was doing some research on this keyboard, I found that some people said that the oscillators were analogue but controlled digitally for tuning control, while others said that the oscillators were digital.
After playing with the keyboard and listening to the waveforms, I can confirm that the waveforms are produced digitally. I found that some of the waveforms would distort as they got quiet which was common for audio sampled at 8 bit.
To give the keyboard a stereo spread sound, the HT-700 features a stereo chorus. I am unsure if the chorus is analogue or digital, but it makes the keyboard sound warm and fluffy. The chorus has three settings, with each setting changing the intensity of the effect.
One strange thing that I have found with the chorus is that some of the waveforms will distort or clip. Pre sets like the Jazz Organ distort when used with the chorus and the only way that I could stop the distortion was to lower the amplifier envelope depth. I’m not sure if this is just a problem with my HT-700 or if it was a common problem with all of the Spectrum Dynamic synthesisers. The chorus settings apply to the main voices, chord voices and bass voice.
One thing that makes the HT-700 so popular is its analogue Voltage Controlled Filter (VCF). The filter can be used to create those classic analogue sounds commonly associated with synths like the Mini Moog or Roland Jupiter.
As the HT-700 only has 2 VCFs (1 for the main voice and 1 for the chord voice) the filter envelope re-triggers each time a new note is pressed.
The filter has resonance, but it is not capable of self-oscillating. I have heard that some people have modified the filter to give it more depth and to allow it to self-oscillate.
The two buttons below the jog wheel are labelled ‘Mode’ and ‘Data’.
When the ‘Mode’ button is pressed, the keyboard is placed into ‘Edit’ mode and the LCD screen displays the parameter number. If the ‘Data’ button is pressed, the parameter settings can be edited, for example, if the user wanted to change the oscillator waveform, the user would press the ‘Mode’ button, move the jog wheel until it displays the number ‘00’ and then press the ‘Data’ button. When the waveform that the user wants has been selected, they simply press the ‘Mode’ button again and then edit the other parameters.
The jog wheel is in fact analogue. I was expecting the wheel to be digital like what you would find on some new car stereos. While I like the smooth feel of the jog wheel, being analogue can make it a bit of a nuisance at times, for example, if you changed the oscillator waveform to 31, which involves moving the jog wheel all the way to the end, and then wanted to transpose the keyboard, you would have to move the jog wheel back to find the correct parameter number.
When programming the keyboard, the manual is vital for knowing which number correspond to which parameter. The keyboard has a small table just above the LCD screen that briefly tells you which number corresponds to which parameter, however it lists them as groups e.g. 00 – 10 corresponds to the oscillator and LFO.
I think they changed this with the HT-6000 as they printed the full parameter list on the top of the keyboard.
I have created a PDF file which list which parameter corresponds to the numbers shown on the screen. You can download it for free here
The LCD screen has some indicators that tell you if you are editing the chord or main voice.
The keyboard has a total of 32 waveforms to choose from (the waveform settings start at 00). Some can sound warm and analogue while others can sound metallic and gritty. A few of the waveform’s timbre or textures can change over time, some of which can be controlled with the amplifier envelope. A good example of this is waveform number 9.
This gradual change in harmonics is what differentiates ‘Spectrum Dynamic Synthesis’ to the standard ‘Subtractive Synthesis’.
The HT-700 features two Low Frequency Oscillators (LFOs), which is fixed to modulating the pitch. The LFO for the main voice has 5 waveforms; Triangle, Descending Sawtooth, Ascending Sawtooth, Square and a Random waveform.
It is also possible to program the chord voice as well. Programming the chord voice is similar to programming the main voice although the chord section does not have as many features. The chord voice has only 16 waveforms instead of 32 and the LFOs waveform is fixed to a triangle wave.
The HT-700 lacks the lower tone buttons found on the other keyboards in the Spectrum Dynamic range, so the only way to save a chord voice is by pressing one of the auto accompaniment buttons.
The HT-700 does not feature a battery backup so all voices saved in the internal memory will be lost if the keyboard is disconnected from a power source.
While I was doing some research on this keyboard, I found that some people said that the oscillators were analogue but controlled digitally for tuning control, while others said that the oscillators were digital.
After playing with the keyboard and listening to the waveforms, I can confirm that the waveforms are produced digitally. I found that some of the waveforms would distort as they got quiet which was common for audio sampled at 8 bit.
To give the keyboard a stereo spread sound, the HT-700 features a stereo chorus. I am unsure if the chorus is analogue or digital, but it makes the keyboard sound warm and fluffy. The chorus has three settings, with each setting changing the intensity of the effect.
One strange thing that I have found with the chorus is that some of the waveforms will distort or clip. Pre sets like the Jazz Organ distort when used with the chorus and the only way that I could stop the distortion was to lower the amplifier envelope depth. I’m not sure if this is just a problem with my HT-700 or if it was a common problem with all of the Spectrum Dynamic synthesisers. The chorus settings apply to the main voices, chord voices and bass voice.
One thing that makes the HT-700 so popular is its analogue Voltage Controlled Filter (VCF). The filter can be used to create those classic analogue sounds commonly associated with synths like the Mini Moog or Roland Jupiter.
As the HT-700 only has 2 VCFs (1 for the main voice and 1 for the chord voice) the filter envelope re-triggers each time a new note is pressed.
The filter has resonance, but it is not capable of self-oscillating. I have heard that some people have modified the filter to give it more depth and to allow it to self-oscillate.
MIDI Capability
The HT-700 has basic MIDI support and can be used as either a tone generator or a MIDI controller.
When being used as a tone generator, the keyboard can operate in two modes; single-timbral and multi-timbral. When the keyboard is in single-timbral mode, only the main voices are used and the keyboard can play up to 8 notes.
I mainly use this mode when recording my music with the keyboard especially if I am using a voice with a long release (takes a long time to quiet down after a key has been released), as this will prevent the notes from being cut off early.
Multi-timbral mode splits the keyboard into 4 parts and the maximum number of notes is divided between them.
Part 1 uses the main voices and has 4 notes of polyphony.
It is accessed on the send and receive channel.
Part 2 uses the chord voices and can only play 3 notes.
This part is accessed by taking the send and receive channel and adding 1 i.e. if the send and receive channel is 1 then part 2 will be channel 2.
Part 3 is a monophonic bass section, which is accessed by adding 2 to the send and receive channel.
Part 4 is the rhythm section and it is accessed by adding 3 to the send and receive channel.
Although the drums cannot be sequenced via midi, it is possible to cycle through the built in and user programmed auto accompaniment styles by sending voice changes.
The HT-700’s midi clock supports both internal and external modes which make it easier to sync the drums with a Digital Audio Workstation (DAW).
On some recordings, I sampled the HT-700’s drums into a sequencer and sequenced them. I found this useful as it allows me to start and stop the drums at any time.
It is also possible to access an additional octave by using a MIDI controller. This is probably because the HT-3000, which is also a spectrum dynamic synth has this extra octave.
My biggest complaint about the HT-700’s MIDI support is the lack of velocity support (how hard a note was pressed).
I know that the keyboard’s keys are not velocity sensitive but what bugs me is that the auto accompaniment chords and bass output the accents as velocity data, so surely Casio could have given us the option to transmit velocity data to it.
This also means that if you record an auto accompaniment pattern with accents on it and then play it back on the keyboard, the accents will be missing.
When being used as a tone generator, the keyboard can operate in two modes; single-timbral and multi-timbral. When the keyboard is in single-timbral mode, only the main voices are used and the keyboard can play up to 8 notes.
I mainly use this mode when recording my music with the keyboard especially if I am using a voice with a long release (takes a long time to quiet down after a key has been released), as this will prevent the notes from being cut off early.
Multi-timbral mode splits the keyboard into 4 parts and the maximum number of notes is divided between them.
Part 1 uses the main voices and has 4 notes of polyphony.
It is accessed on the send and receive channel.
Part 2 uses the chord voices and can only play 3 notes.
This part is accessed by taking the send and receive channel and adding 1 i.e. if the send and receive channel is 1 then part 2 will be channel 2.
Part 3 is a monophonic bass section, which is accessed by adding 2 to the send and receive channel.
Part 4 is the rhythm section and it is accessed by adding 3 to the send and receive channel.
Although the drums cannot be sequenced via midi, it is possible to cycle through the built in and user programmed auto accompaniment styles by sending voice changes.
The HT-700’s midi clock supports both internal and external modes which make it easier to sync the drums with a Digital Audio Workstation (DAW).
On some recordings, I sampled the HT-700’s drums into a sequencer and sequenced them. I found this useful as it allows me to start and stop the drums at any time.
It is also possible to access an additional octave by using a MIDI controller. This is probably because the HT-3000, which is also a spectrum dynamic synth has this extra octave.
My biggest complaint about the HT-700’s MIDI support is the lack of velocity support (how hard a note was pressed).
I know that the keyboard’s keys are not velocity sensitive but what bugs me is that the auto accompaniment chords and bass output the accents as velocity data, so surely Casio could have given us the option to transmit velocity data to it.
This also means that if you record an auto accompaniment pattern with accents on it and then play it back on the keyboard, the accents will be missing.
My final thoughts
The Casio HT-700 is definitely one of my favourite keyboards. It’s easy to program and a wide variety of voices can be created.
The keyboard can also create great pads thanks to its evolving waveforms and the built in stereo chorus gives it a nice stereo spread.
I love the fact that you can create your own auto accompaniment styles to jam along with.
I would have preferred if the keyboard had more features that could be accessed via MIDI, like sequencing the drums individually and velocity support.
I would definitely recommend this keyboard.
Click here to read my review of the non-programmable version of this keyboard, the Casio MT-600.
Some videos I did featuring this keyboard
To view a complete playlist of songs I made with this keyboard, click here
The keyboard can also create great pads thanks to its evolving waveforms and the built in stereo chorus gives it a nice stereo spread.
I love the fact that you can create your own auto accompaniment styles to jam along with.
I would have preferred if the keyboard had more features that could be accessed via MIDI, like sequencing the drums individually and velocity support.
I would definitely recommend this keyboard.
Click here to read my review of the non-programmable version of this keyboard, the Casio MT-600.
Some videos I did featuring this keyboard
To view a complete playlist of songs I made with this keyboard, click here
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Copyright © 2015 Stereo Ninja Music
If you would like to provide feedback on this post, feel free to use the contact form on the Contact page
Disclaimer
If you see my keyboard images and blog posts on online auction sites, it’s most likely that the seller has taken my content without my permission. I am not affiliated with any of these sellers and I cannot be held responsible for the items they are selling.
Stereo Ninja Music does not sponsor or endorse these other videos and cannot be held responsible for their content.
Mobile users, I recommend you watch my videos from the official YouTube app as it is optimised for the smaller screen size.
Copyright © 2015 Stereo Ninja Music
If you would like to provide feedback on this post, feel free to use the contact form on the Contact page
Disclaimer
If you see my keyboard images and blog posts on online auction sites, it’s most likely that the seller has taken my content without my permission. I am not affiliated with any of these sellers and I cannot be held responsible for the items they are selling.