Thanks, I grew up in the 80's and my brother had a Casio melody calculator, this overview helped me remember. Not sure what model but a vertical one. I'll watch your other calc videos to help me remember. :)
Casio VL-1 and classic PT-series have the same sound engine, which is one multipulse squarewave with linear volume envelope and LFO. But to bust a myth, this synthesis is not "Walsh". It may be that the idea of synthesizing timbres this way originated from Walsh (there was that Allen Organ patent lawsuit), but multipulse squarewave is not identical with Walsh. Layering multiple Walsh drawbars would still sum them with different volume levels, while within a multipulse (16 bit steps those each can be hi or lo) the steps always keep the same height (i.e. 1-bit signal of repeating 16 steps). I remember I read in a magazine(?) long ago an interview that Casio had invented multipulse squarewave coincidentally when they experimented with LCD control voltages for calculators (consisting of blocky 4 step (2-bit) waveforms) and noticed that they sounded like organ tones. I also doubt that consonant-vowel or SD internally layers actual Walsh drawbars (which are a series of certain mathematically well defined special multipulses). It simply crossfades/morphs between 2 blocky waveforms (and than layers 2 or 4 of them having different preset analogue filters) to synthesize timbres. The internal basic waveforms were likely tweaked by ear and not planned to implement Walsh. Walsh makes only sense when you want to be capable to systematically approximate all repeating waveforms by summing a high number of multipulses in the same manner like conventional drawbars sum sines (implementing the Fourier series).
I don’t think the calculators had the processing power to compute Walsh functions. Afaik they were only employed on 10,000 dollar Allen digital organs. There was confusion or speculation about the Walsh functions potentially being associated with Casio because of Allen organs patent lawsuits at the time but I don’t think the lawsuits were related to Walsh functions, it was just the basic principles of storing waveforms and phase accumulators which most oscillators used.
You're probably right, though whenever you search online for info about the VL-1 tone generation, and the related calculators, it's claimed to be generated by Walsh Function. Maybe Casio used a single formula originally generated by Walsh function for the Melody calculator series, hence only one sound being available?
No, the reason it comes up when you search is that it has probably been copied and pasted from the same original forum discussion / wiki article. Casio’s patents don’t mention Walsh tones afaik. You could also check patent dates for the melody calculators also to get an idea of the priority / release dates.
Us patent 4,294,154 has a priority date of the Japanese patent filing of December 1978. Seems to be one of their earliest musical calculator patents. These only emit square waves anyway so there is nothing to be computed with Walsh functions.
Casio did not use Walsh but only one multipulse squarewave (which is like a single Walsh waveform). Actual Walsh would layer a large number of them, which would have been possible with 1980th hardware (easier than the sines of Fourier), but I found no actual Walsh waveforms in any Casios. Walsh layers a set of special well-defined multipulses, while Casio uses per preset sound only one multipulse, which is tweaked to mimic a natural instrument timbre.
Thanks, I grew up in the 80's and my brother had a Casio melody calculator, this overview helped me remember. Not sure what model but a vertical one. I'll watch your other calc videos to help me remember. :)
Great idea for a series, I collect calcs too - brilliant, can't wait to watch.
Casio VL-1 and classic PT-series have the same sound engine, which is one multipulse squarewave with linear volume envelope and LFO. But to bust a myth, this synthesis is not "Walsh".
It may be that the idea of synthesizing timbres this way originated from Walsh (there was that Allen Organ patent lawsuit), but multipulse squarewave is not identical with Walsh. Layering multiple Walsh drawbars would still sum them with different volume levels, while within a multipulse (16 bit steps those each can be hi or lo) the steps always keep the same height (i.e. 1-bit signal of repeating 16 steps). I remember I read in a magazine(?) long ago an interview that Casio had invented multipulse squarewave coincidentally when they experimented with LCD control voltages for calculators (consisting of blocky 4 step (2-bit) waveforms) and noticed that they sounded like organ tones. I also doubt that consonant-vowel or SD internally layers actual Walsh drawbars (which are a series of certain mathematically well defined special multipulses). It simply crossfades/morphs between 2 blocky waveforms (and than layers 2 or 4 of them having different preset analogue filters) to synthesize timbres. The internal basic waveforms were likely tweaked by ear and not planned to implement Walsh. Walsh makes only sense when you want to be capable to systematically approximate all repeating waveforms by summing a high number of multipulses in the same manner like conventional drawbars sum sines (implementing the Fourier series).
Still have my VL1. Still use it to make music (not as a calculator!) Beautiful little thing.
very cool series!!
I have so many Casio keyboards to collect lol.. HT700 and CPS101 are my latest and most recent acquisitions so YAY ME! VL1 would be nice..
I guess all of this must have inspired Kraftwerk? Nice work CCT.
Or more likely, Kraftwerk inspired Casio! :D
I don’t think the calculators had the processing power to compute Walsh functions. Afaik they were only employed on 10,000 dollar Allen digital organs. There was confusion or speculation about the Walsh functions potentially being associated with Casio because of Allen organs patent lawsuits at the time but I don’t think the lawsuits were related to Walsh functions, it was just the basic principles of storing waveforms and phase accumulators which most oscillators used.
You're probably right, though whenever you search online for info about the VL-1 tone generation, and the related calculators, it's claimed to be generated by Walsh Function. Maybe Casio used a single formula originally generated by Walsh function for the Melody calculator series, hence only one sound being available?
No, the reason it comes up when you search is that it has probably been copied and pasted from the same original forum discussion / wiki article. Casio’s patents don’t mention Walsh tones afaik. You could also check patent dates for the melody calculators also to get an idea of the priority / release dates.
Us patent 4,294,154 has a priority date of the Japanese patent filing of December 1978. Seems to be one of their earliest musical calculator patents. These only emit square waves anyway so there is nothing to be computed with Walsh functions.
Us patent 4,336,598 Was lodged in Japan November 30th 1978. So one month earlier. This has more details on the pitch generation method.
Casio did not use Walsh but only one multipulse squarewave (which is like a single Walsh waveform). Actual Walsh would layer a large number of them, which would have been possible with 1980th hardware (easier than the sines of Fourier), but I found no actual Walsh waveforms in any Casios. Walsh layers a set of special well-defined multipulses, while Casio uses per preset sound only one multipulse, which is tweaked to mimic a natural instrument timbre.