From the original SynthMaker forum (2004–2014), with its members’ names and dates.
lesobrod ·
Hi people!
I try to ask a couple of question about modulation or LFO.
It's not for emergency 😉 but maybe for a good discussion.
1. From what frequency it's possible to talk about modulation, not a new sound?
Let's modulate some brown noise by Sin OSC. 1 Hz is LFO, isn't it?
There is a noise and some changes of it's volume.
OK let we take 100 Hz mod freq. For my hearing it's not LFO,
just another noise with a bit another spectrum.
What about 50 Hz? Somewhere should be an edge, isn't it?
Change Cut freq of noise make another impression "LFO or not".
Frankly I've learned much enough about it some times ago from music theory and psychoacoustics.)))
But SM gives me a great instruments for discovering of sound and hearing.
So I rediscovery many things again.
Is it all about s.c. Hearing Critical Bands, isn't it?
2. There was many many posts about SM Trig "work-frequency".
Enough 100 Hz or not? OK I made very simple osm for to hear and think about it.
From what "Get-Mono value Trigger" freq, a ladder, "footstep" effect will disappear?
It seems to me, 100 Hz is not enough even for 1 Hz LFO. De-Zipper is a sweet thing,
but from ~ 10 Hz LFO DZ don't help. There is some "roughness" (is there such word in English??)
Hop(32) is much better but Code is difficult to join with some Trig chains.
So will be glad any opinions. SM forum rules! 😍
MegaHurtz ·
Logically 😕 The edge would be 22hz, where the brain stops picking up frequencys.
Only an intermodulating (or aliassing) pattern is recognised even if it exceeds our maximum threshold,
this because it in term creates higher and lower frequencys.
lesobrod ·
Is 22 Hz valid for all brains? What if we will be modulate a music sound, not noise?
Please give me a link about 22 Hz. This is not a carping, 😀 I'm really interesting about it!
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😠
If there is noise with enough high Cut and some Res, my hearing lost LFO feeling after 100 Hz mod or higher!
MegaHurtz ·
Ighh.. Sort of.
I bet if you scare someones pants off he would hear lower frequencys 😀
Here they say 20Hz also fine with me, guess everyone has its own take on the matter.
Personally id like to take the parallel with the visual framerate, i reckon its about the same.
Guess thats mental too.
http://en.wikipedia.org/wiki/Hearing_range
trogluddite ·
lesobrod wrote: 1. From what frequency it's possible to talk about modulation, not a new sound?
I would say there are two answers...
A) Perceptual - it is a new sound, rather than an evolving version of the 'old' sound, whenever you listen and that's what your brain interprets it as.
B) Technical - False dichotomy. The mathematical relationship between the frequencies is identical, it is always just moduation.
22Hz?
I have no doubt that we are all slightly different in this respect, just as we are with the upper limits of hearing.
The often quoted '20Hz-20kHz' hearing range, and equal-loudness curves, were constructed statistically by correlating data collected from a large sample of people.
I'm not sure how long ago this was done, or which particular population of humans were the test subjects. They are certainly useful "ball park" numbers, but there is always a chance that the data are skewed. Maybe all of the test subjects had 'damaged' perception from trying to block out the noise from a busy city their whole life? Maybe we have recently evolved a heightened perception of low frequencies to help us avoid getting run over by a truck?
Triggers and de-zippers
Yes, as you have found 100Hz is not so good; and the tick100 rarely even gets to 100Hz - around 60Hz is more typical. The timing also has a lot of jitter - the intervals between ticks can change hugely from tick to tick.
The dezipper is pretty good for avoiding horrible noises when moving controls, but it is not prefect for smoothing waveforms. It is just a simple slew-rate limiter - each time the float input changes, the output glides at a constant rate up or down to the new value, then flattens out.
So a sine will always be distorted somehow, depending how the slope of the waveform relates to the slope of the slew rate limiting (hook one up to a scope to get a feel for it).
It works well at low frequencies simply because the intervals between successive values are small - so small that we can't perceive them as individual gain change events, especially once the slew rate limit has joined them up with small slopes (without the de-zipper, the broad-band noise of the step transients would give the game away).
MegaHurtz ·
Yes.. Rather than regurgitating wiki. This is what they told me in academic audiodesign classes.
Wiki tends to be contradicting itself from time to time. But when i get home from work ill hook up my subs for the fun of it 🙂
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