Spin Semiconductor

[Mel]

Hey, Just got into programming the FV-1 and I'm looking for advice
on how to implement a swell/slow gear effect

the general idea is to trigger a ramp envelope when a certain
input threshold is reached?

thnx

[livingston]

If you search the forum for envelope detection (or check out the Knowledge Base on the main site) you'll see some code examples to find the input envelope. Once you have that you can use something like SOF 1.9,-1 to make the envelope go from -1 to 1, then use SKP NEG to find when the input goes above zero. Within the skipped area, you can initialize the ramp and then MULX your input signal with the ramp.

Or, one thing I thought about but haven't tried is to just take the input envelope, SOF -1,.999 so that you have backwards envelope and just MULX your input signal with the backwards envelope. This way, when you play hard, the output envelope is brought to zero, and as your guitar note fades it rises in volume.

[B.C.]

I can get a pretty good slow gear impression by using a regular reverb with increasing tap coeff.

[Mel]

So, I tried something like this but I'm pretty stuck at this point since
It really does nothing:
______________________________

fil equ reg0
inverse equ reg1


rdax adcl,1.0
ABSA
RDFX fil,1
WRLX fil,1
SOF -1,0.999
wrax inverse ,0


rdax adcl,1.0 ; Read ADC left
mulx inverse
wrax dacl,0 ; write to DAC left

[livingston]

[donstavely]

Here is a different approach you could consider. I have been working on a note detector triggering a ramp generator for another project. Just using a pot to adjust the ramp rate, and then multiplying the input signal by this ramp gives you a slow note attack.

This code may be useful for many kinds of projects. I offer it to the forum hoping that others will use it, improve on it, and post post it back.

[Mel]

thnx guys(!!!),

livingston, tried using your coefficients but as far as can Tell what
i get is the regular instrument sound

donstavely, im afraid your code is beyond my level of understanding right now so sadly i plan to keep on struggling with something simpler

[livingston]

Hmm, if I get a chance I'll try the code above and see what I can make of it. As I said, I hadn't ever tried that concept, but I think it should work if we can get the code together.

One thing you might try is amplifying your instrument, either in analog before the FV-1, or by putting several "SOF -2,0" statements in a row (always use an even number of these). The problem could be that your instrument isn't loud enough to create a big enough envelope. Also try playing with the WRLX coef.

[patb]

Great slow gear program, nice one
never could get mine to work properly !
Try this though:-

; Note trigger and timer ramp
maxx envlop,0.9995
wrax envlop,1 ; envelope filter, leave in ACC
rdfx peak,0.002 ; high-pass filter to differentiate
wrhx peak, -1 ; no shelf
rdfx peak,0.002
wrhx peak, -1
rdfx peak,0.002
wrhx peak, -1
rdfx peak,0.002
wrhx peak, -1
;
skp gez,1
clr
log 1.999,0.5
wrax trig,0