You do that sound using two oscillators synched. Where one oscillator(the modulator/master) is used to restart the period of the waveform of the other oscillator (the sound generator/slave).
Then you just sweep the pitch of the modulator.
In this specific case the modulator is being stepped up a key scale quite slowly.
You get far best results using some analog hardware for this (like the sid chip which also adds distortion and other “side effects”).
Then there is also some standard ADSR and filtering involved.
Your best chance recreating the sound would be to actually use a sid chip obviously
Use a simple saw sample, add a ringmod device with a harmonic frequency and you’re there. What waveform you use for ring modulation is a matter of taste. I guess a triangle should work fine for your reference sound. For the sweep just lift the modulation amount and/or the frequency (to the next harmonic frequency) of the ringmod device.
Neither any filtering nor any volume envelopes or distortion are required. The phase deletion and amplitude modulation caused by the ringmod makes it sound like filtered, distorted and varying volume.
Bit_Arts is right.
Consider all the distortion in the example clip it is probably the ringmod used.
The oscillator sync gives a very similar sound as well and can also give quite a distorted sound on the c64.
But the key essence of this sound is recognized by the upward key scaling modulator in any case.
Not really. Actually my own description above isn’t correct. Modulating/Lifting the ringmod frequency ends up in another effect.
If anyone is interested in what’s happening in the example:
The point behind the effect is to use the STATIC frequency of the base note of our sequence (octave might differ). In the example the base note is a “A”. Ringmodulating an A with an A (440Hz = A4) makes the tone still an A. But as soon as a different note than an A is played the ringmodulation results in harmonic frequencies of A added to the currently played note. And with moving the “amount”-slider we just lift the volume of the added harmonic frequencies.
Ok, I could not resist and had a closer look at it
I fired up my Hardsid and tried to reproduce it and also soloed the tracks of the ninja sid tune.
Seems we are both right and wrong here.
The modulation is a slow triangle sweep up (for some reason I remembered another SID tune using step upwards instead of sweeps, but that must be another last ninja tune I guess, I remembered it wrong anyway…)
Now the more tricky part:
The modulator oscillator is BOTH syncing and ringmodulating another oscillator.
After a few tests I’m also pretty sure the oscillator being modulated is actually passive (all waveforms disabled, but still triggering notes for the bassline).
The sid chip is very routing friendly, but is bleeding and “out of specs” in many ways. So a lot of tricks and bugs can be used to produce unorthodox sounds.
Anyway. If you want to nail that sound, then get a c64 or a hardsid. The soundclip you linked to is also an emulator I would guess (or really bad encoded afterwards).
You can listen to a real sid playing the tune here: here
You can do the ringmod trick like Bit_Arts showed you and get half the way. But there is no really effective way to hardsync wavesforms natively in renoise.
You better find a flexible vst for that.
Still, no emulator will sound exactly like the hardware SID.
