KVR Audio

mistertoast · Post by **mistertoast** » Sun Sep 13, 2009 1:42 am

mystran wrote:Less arguing, more dancing (neither fish nor hardware were harmed making the above clip).

Heh. That sounds pretty sweet.

rlahalla · Post by **rlahalla** » Sun Sep 13, 2009 2:03 am

mystran wrote:Less arguing, more dancing (neither fish nor hardware were harmed making the above clip).

Hey hey, did you make that? Sounds really cool! Nice job

mystran · Post by **mystran** » Sun Sep 13, 2009 4:40 am

rlahalla wrote:
mystran wrote:Less arguing, more dancing (neither fish nor hardware were harmed making the above clip).
Hey hey, did you make that? Sounds really cool! Nice job

Hehe, yeah well, that's just some patterns pulled from a crappy psytune I'm working on. The synth (obviously inspired by 303 though not really a proper model) I wrote in the last couple of days (well, I lifted a lot of code from some other projects) but it needs some more care and love before I'll let it into the wild..

antto · Post by **antto** » Sun Sep 13, 2009 8:35 am

mystran: cool

antto · Post by **antto** » Sun Sep 13, 2009 10:15 am

i tested the FEnv curve against the audio sample from acidvoice, it matches there too, the min/max decay too
so now i can give you the curve and the time ;]

curve: -0.2938485 / (1.0 + -608.94871 * exp(-6.1539216 * x))
x is your linear envelope.. 1 to 0.. (decaying)

min decay: 0.341
max decay: 4.310

mistertoast · Post by **mistertoast** » Sun Sep 13, 2009 3:18 pm

I'm still not sure what this curve is. FEnv is the filter envelope, right? What does this curve control? The cutoff during decay?

brambos · Post by **brambos** » Sun Sep 13, 2009 4:47 pm

Hey Antto.. I haven't been able to try all your findings out yet, but here's a big

for all your detective work!

antto · Post by **antto** » Sun Sep 13, 2009 4:58 pm

mistertoast wrote:I'm still not sure what this curve is. FEnv is the filter envelope, right? What does this curve control? The cutoff during decay?

imagine this wasn't a TB-303 but a simple/standart/basic subtractive synthesizer
where you have OSC, Filter, VCA, and ADSR envelopes for the filter
now set Attack to 0 (fastest, or instant) Sustain to 0, Release to 0
you are left with only Decay
usualy an ADSR would be linear, just like mine (which btw is the standart SynthEdit ADSR module)
now if you shape the output of the Decay envelope (before it goes to the filter cutoff frequency) with the curve i posted, you'll get a TB-303 feel ;]
you probably have heard how a TB-303 sounds when the Reso & EnvMod are high, Decay is low, and cutoff is being modulated (sounds like liquid to me)
it sounds like it does mostly because of this curve ;]
any different curve and you'll hear that it's kind of liquid, but not a TB-303

mistertoast · Post by **mistertoast** » Sun Sep 13, 2009 5:01 pm

antto wrote:
mistertoast wrote:I'm still not sure what this curve is. FEnv is the filter envelope, right? What does this curve control? The cutoff during decay?
imagine this wasn't a TB-303 but a simple/standart/basic subtractive synthesizer
where you have OSC, Filter, VCA, and ADSR envelopes for the filter
now set Attack to 0 (fastest, or instant) Sustain to 0, Release to 0
you are left with only Decay
usualy an ADSR would be linear, just like mine (which btw is the standart SynthEdit ADSR module)
now if you shape the output of the Decay envelope (before it goes to the filter cutoff frequency) with the curve i posted, you'll get a TB-303 feel ;]
you probably have heard how a TB-303 sounds when the Reso & EnvMod are high, Decay is low, and cutoff is being modulated (sounds like liquid to me)
it sounds like it does mostly because of this curve ;]
any different curve and you'll hear that it's kind of liquid, but not a TB-303

So you're talking about the amplitude of the signal being affected, not anything about the filter.

I guess I'm looking for a one word answer. What is the curve you gave us affecting?

antto · Post by **antto** » Sun Sep 13, 2009 5:13 pm

no, this is not part of the filter itself
it's just a wave shaper that i apply to my linear envelope (Decay) to get the propper filter modulation curve seen on the FFT

you know, some say "logarithmic envelope" or "exponential" or "linear"
this is exactly the same, only it doesn't seem to be any of these

in other words, if you look how the cutoff (with a lot of resonance) travels on the FFT (when you're looking at a TB-303 sample) you'll see that it is not linear, it falls down fast in the begining, then slower and slower

this is very important part of the TB-303 since you hear it all the time ;]

brambos · Post by **brambos** » Sun Sep 13, 2009 5:16 pm

antto wrote:no, this is not part of the filter itself
it's just a wave shaper that i apply to my linear envelope (Decay) to get the propper filter modulation curve seen on the FFT

you know, some say "logarithmic envelope" or "exponential" or "linear"
this is exactly the same, only it doesn't seem to be any of these

So it affects the cutoff variable?

min decay: 0.341
max decay: 4.310

What are these? Seconds?

Thanks!

antto · Post by **antto** » Sun Sep 13, 2009 5:19 pm

brambos: A1: yes.. your envelope (that modulates the filter cutoff) must look like this curve to sound like a TB-303

A2: yes, seconds, but they are valid only if you use linear envelope + my curve ;]

Kriminal · Post by **Kriminal** » Sun Sep 13, 2009 5:24 pm

antto wrote:
you know, some say "logarithmic envelope" or "exponential" or "linear"
this is exactly the same, only it doesn't seem to be any of these

in other words, if you look how the cutoff (with a lot of resonance) travels on the FFT (when you're looking at a TB-303 sample) you'll see that it is not linear, it falls down fast in the begining, then slower and slower

isnt that what a logarithmic curve does?

mistertoast · Post by **mistertoast** » Sun Sep 13, 2009 5:40 pm

OK. So your curve describes how the cutoff moves through time. And once again I'm baffled as to how you came up with this graphically without taking multiple screenshots through time.

antto · Post by **antto** » Sun Sep 13, 2009 5:53 pm

yes, the envelope decays in time, but this curve doesn't change with different values of the Decay knob (on the TB-303)
it appears more like a simple waveshaper applied to a linear envelope (at least, this is what i'm doing here, and it works/looks the same)

multiple screenshots? why?!
i got FFT ;]
oh, now i think i understand your question
when i say "FFT" you probably think of something like the Voxengo Span VSTi which is realtime FFT or something, it shows you the FFT curve of the sound in realtime (i think this is called a SpectroScope)

while i use something different, it's more like a SpectroGraph
SoundForge -> Spectrum analysis
btw, if it's not like that, i won't find looking at an FFT useful (if it was like a spectroscope)

Open303 - open source 303 emulation project - collaborators wanted