Need noise generator for creating analog supersaw.

[JonasNorberg]

I've measured the pitch Unstable "Speed" (8.040) + "Amount" (0.001) parameters' affect

Hi Arch. The unstable in Helix is achieved by white noise through a one-pole filter.

At a technical note, the control-rate for the pitch is a 32nd of the sample-rate, with linear interpolation in between.

Jonas

[Architeuthis]

Aha, that's why using Helix's noise generator (which when lowered in pitch is almost like lowering sample rate) and filter plus my slew limiter gave me a similar result. I could create the same affect with any noise generator using a sample-rate reduction.

[michu]

Aha, that's why using Helix's noise generator (which when lowered in pitch is almost like lowering sample rate) and filter plus my slew limiter gave me a similar result. I could create the same affect with any noise generator using a sample-rate reduction.

Archi, do you have an analogue S&H module among your toys? you could try feeding noise into it with oscillator as a clock and then feeding the output back into osc's FM input

[antto]

i have already made a synth with some "analog drift" with SE (venom vb-303) tho, it only has 2 oscillators, no matter how many instances you load and if you play the exact same patterns with the synth, each oscillator will go in a different direction

i used a pseudo-random-number-generator (PRNG) based on 32bit integers, which is converted to floats, the result is nice and cheap white noise
but the initial seed of this PRNG is based on the TIME+CPU_TICKS+some_constant so.. ;]

..and the output of this is filtered by a 12dB SV (LP) Filter..

not sure if this is helpful, but anyway..

[soapform]

Hi, thought I'd chime in.

Filtering noise straight doesn't work well because you're filtering the energy away, so the amount of shift you get diminishes when you make the variations longer. Adding a sample and hold module between the filter and the noise, or using a slew limiter as you did should do the trick...

Another pointer, usually it gives better results to have LFO control the frequency linearly, than by pitch. Let me illustrate with an extreme example, suppose you have a square wave modulating the pitch around 1000 hz by an octave. at the upcycle it's 2000 hz and at the downcycle it's 500 hz, which averages out to 1250 hz! this means the sound will upshift on average. so it's better to modulate linearly between 500 hz and 1500 hz, this way it'll sound more centered to the note you are playing.

BTW, Martin Walker, are you the same guy who did that mesmerizing music to C64 games like Armalyte and Snare?

[JonasNorberg]

Aha, that's why using Helix's noise generator (which when lowered in pitch is almost like lowering sample rate) and filter plus my slew limiter gave me a similar result. I could create the same affect with any noise generator using a sample-rate reduction.

You are right that the noise oscillator generates S&H-noise.

But the unstable-noise is a separate noise generator, through a one-pole-filter.

[JonasNorberg]

Filtering noise straight doesn't work well because you're filtering the energy away, so the amount of shift you get diminishes when you make the variations longer.

That's what happens in Helix. To me it sounds good. If you close a low pass filter on an audio source the amplitude diminishes too.

Another pointer, usually it gives better results to have LFO control the frequency linearly, than by pitch. Let me illustrate with an extreme example, suppose you have a square wave modulating the pitch around 1000 hz by an octave. at the upcycle it's 2000 hz and at the downcycle it's 500 hz, which averages out to 1250 hz! this means the sound will upshift on average. so it's better to modulate linearly between 500 hz and 1500 hz, this way it'll sound more centered to the note you are playing.

Did you really try this? To me thinking about Hz makes less sense than pitch, if you calculate your average value using the pitches you'll see that there is no pitch-shift. Our perception works with pitches, so doing vibratos in pitch sounds like the error up and down are the same.

Jonas

[Architeuthis]

Archi, do you have an analogue S&H module among your toys? you could try feeding noise into it with oscillator as a clock and then feeding the output back into osc's FM input

Interesting idea, so like this?

Noise --> S&H Audio Input
Oscillator --> S&H Clock Input
S&H Output --> Oscillator FM Input

By the way, I don't have an analog noise or S&H, my current setup is very limited, 4 VCA, 1 Oscillator, 2 HP/LP filters, 1 ADSR, 1 envelope follower, one reversable attenuator module with 4 in/out

[soapform]

Did you really try this? To me thinking about Hz makes less sense than pitch, if you calculate your average value using the pitches you'll see that there is no pitch-shift. Our perception works with pitches, so doing vibratos in pitch sounds like the error up and down are the same.

maybe you're right - I just tested both ways, and the difference wasn't too big. the "hz method" has a similar sound to a delay based vibrato effect, where the sound doesn't get "ahead of itself".

[michu]

Archi, do you have an analogue S&H module among your toys? you could try feeding noise into it with oscillator as a clock and then feeding the output back into osc's FM input

Interesting idea, so like this?

Noise --> S&H Audio Input
Oscillator --> S&H Clock Input
S&H Output --> Oscillator FM Input

By the way, I don't have an analog noise or S&H, my current setup is very limited, 4 VCA, 1 Oscillator, 2 HP/LP filters, 1 ADSR, 1 envelope follower, one reversable attenuator module with 4 in/out

exactly, kind of a feedback.
noise doesn't have to be analogue, S&H unfortunately does. digital latency would introduce artifacts i guess...
i'd put some digitally generated examples, but my creamware scope rig is down at the moment

[MWSOS]

BTW, Martin Walker, are you the same guy who did that mesmerizing music to C64 games like Armalyte and Snare?

Yes, that's me soapform

Sorry for the thread hijack Architeuthis


Martin