Looking for some help on audio rate modulations with CV on the Iridium.
I keep getting this “cyclic aliasing” and I want to figure out why it’s happening.
In the video I’m using CV to change the wave table position with a sine wave (same frequency as the note I play).
If I do the same thing (modulating WT Pos with a sine wave) using Kernals, it’s stable and sounds good. But with CV, I keep getting these artifacts, and the same artifacts happen when I map CV to pitch, etc. it’s not just wave tables.
So, first, this disclaimer: I don’t have an Iridium (yet), but I’ve been hungrily following this thread and appreciated your contributions.
One thing it could be is, as you mention at the end, a sort of “sample rate mismatch.” The Iridium may only sample its CV inputs at a certain rate that is somewhere below audio rate (if the designers did not expect audio rate modulation, this would be a way to save CPU – you can sample a sine wave moving at LFO speeds well below audio rate and still have much higher resolution than MIDI, for instance, so no zippering, etc. artifacts).
The cyclic aliasing could be the result of mismatch in rates producing phase shift in the sine wave, as different samples would begin at different points in its cycle (and maybe the strongest evidence toward that is that we hear the aliasing rise and fall like a peak of a wave). Kind of like those old flip books which would mimic animation – a horse galloping and so on?
Thanks, @chm_jacques. That’s my guess as well. Maybe we’re hearing true aliasing, just like the illusion of seeing helicopter blades going backwards.
If the sample rate is 44.1 kHz it should give a clean signal (Nyquist frequency).
But if it’s lower than that, like say 100Hz (the LFO speed limit) then maybe we get artifacts like this? Not really sure.
It would make sense if it uses 100Hz sampling as you can map CV to pretty much anything , and the same goes for the LFOs. What you can’t do is map an oscillator to things, outside of Kernels mode. So that kind of leads to a paradox. If the Iridium can do true audio rate modulation, then why restrict it to CV?
Maybe getting audio rate CV mods with so much flexibility was a little too good to be true
The control rates of the modulation matrix are limited to 100hz and below. External CV doesn’t let you surpass that limit; anything higher just gets downsampled.
Yes, that makes perfect sense. It’s disappointing (to me anyway), because the pro3 matrix operates at 48Khz. I was hoping the Iridium would be similar. Adding CV input as a feature made my brain think “external audio rate modulation support!” and it seems that it’s not the case.
Not trying to sound like a mad man but i’ve been wondering about the Iridium vs Wavestate, from an ambient/soundscape perspective.
Originally i was set on getting a Wavestate. I absolutely love the sounds it’s capable of producing in the above mentioned fields but now i’m in a position to buy an Iridium & that feels like a dream come true for me.
But of late i’ve mainly been comparing demos by CO5MA on Youtube @Astrolab
And i have to say i don’t prefer the sound of one over the other. Now i fully appreciate the difference on paper, but does anyone here own both & are you able to share your thoughts on the 2 side by side, in regards to creating pads, soundscape, sound design.
I could buy both but i don’t necessarily want to go down the path of adding more & more things. Just want 1 synth to go with my Akai Force.
In my opinion, they are both amazing synths. But Iridium/Quantum is/are in an absolute different league; the highest one. On Wavestate you can’t import your own samples and that’s the biggest lack imo. You have to create your own sound with (quite) limited factory samples. And some are really cheesy and useless at some point. That’s an amazing synth but it’s locked.
With Iridium, you have access to your own samples, even multisamples, true granular stuff, live granular through audio inputs, Resonator engine, FM/Kernel Engine, Wavetables and, to me, the most intuitive user interface ever made on a synth (thanks to the big touch screen and the amazingly well thought layout)
respected users … be carefully … don’t use a vesa-mount and let the synth hang on it … due it’s weight it bends the metal of the enclosure a bit too much, not in a harmful way but the display appeared to be leveled by a millimetre at the bottom
after i put the vesa away, the display went back in its place
oh man, i thought i bricked the Iridium but everything works fine