Adding vocal track

At the moment we have plenty engines with wavetable and sample playing capabilities.

utz did a great range of wavetable engines that using 256-byte long looped samples, which is enough to represent vowels; I did a number of engines with sample-based percussion of various kinds.

Just a few days ago I released SquatE, which is very close to your Squeeker (thanks a ton for this thing!), plus it features a sample channel that plays along without interrupting the tone channels. This was done exactly with vocal and pitched instrumental samples in mind. It can be done even better, as a song with vocal parts would need good compression, and 1-bit samples seem to be compressible with basic RLE well enough, so the next step would be an engine with on-fly RLE sample decoder, and a wider number of samples (currently numbers limited to 7-15). Perhaps with a sample offset effect, even.

As for a real-time vowel synth, I think we're discussed this possibility at some point somewhere around here. This sure yet to be done.

Been actually thinking about making an engine with a dedicated vocal/speech synth track for quite some time now. 256-byte wavetables is indeed well-suited for this. What I'd really want to do though is formant synthesis. Haven't been able to pull it off yet, though.

My pleasure. Btw. is there some demo song, showing the SquatE abilities with all bells and whistles? Especially, that non-interupting samples must be great.

Definitely. For background chords in the Amiga minor/major style. But still, I think that vocals are even cheaper to play. When 32 samples are enough on GB, are 16 probably as well... and this way, the looping and separation could be trivialised, probably. It's also of little importance, whether the voice sounds harsh, distorted by quantisation - one could take it rather as a feature... we all love robotic voices, especially when they are in-tune .

Great list. Everything there was new for me, nice to see such huge advances in this techinque.

Do you know LPC fundamentals and this marvelous document? https://cnx.org/contents/swFM2W46@5.12: … troduction
It describes details of development of famous 80s SpeakNSpell toy - first LPC voice synthesizer chip. I think while LPC is fully computable on ZX (you can nicely interleave each LPC value processing with pulse width value decrement etc.), microsamples are better suited for this. We really need just few of them, they are ultrashort, might be 1-bit, and there's no computational overhead at all...

Actually, the math behind is a bit misleading. In reality, it's dead-simple. Just few-item array (either round buffer, because there's no need to copy or shift anything, or array with fixed indexes that can be better hardcoded into the loop) and you compute weighted sums of previous items, and this sum is the new item.

Normally, such array would never leave the initial all-zeroes state, so it's also fed with excitation frequency (spikes, because they pre-contain upper harmonics, which are typically suppressed in the predicted output, because it's sum-averaged). That's all.

Have a look also here: https://cnx.org/contents/wh_aQ2UJ@20/Sp … -Synthesis