envelope filter mod

[VolksWilliam]

Hi. This may sound weird but I read somewhere about somebody modding an elevelope filter to affect the volume rather than the tone. To get a swell effect. Does anyone know how I would go about this? I have ggg ef440 that I don't use anymore.

[mac]

Try increasing r12 or decreasing r11.
That would boost the filter and output volume, but it may distort...

If you want more "envelope" increase r5.

I tried some auto wahs and they all have low output. I'm not an expert, I guess if you want more output the filter is going to distort more and more due to the vibrations of the guitar and the gain of the filter itself.

mac

[Mark Hammer]

Hi. This may sound weird but I read somewhere about somebody modding an envelope filter to affect the volume rather than the tone. To get a swell effect.

Well, yes, and no.  "Swell" and "reverse" effects DO make use of a sidechain/envelope-follower, but they do so in a different way.  Remember that an auto-wah treats the entire signal envelope as valid.  The filter sweeps up (or down), and then returns to a starting point.  That starting point might be treated as a "default" tone, to be adjusted by picking harder at some times.

In the case of swell/reverse effect units, the objective is to mimic the envelope of a picked/strummed string, but backwards.  So the amplitude has to get progressively louder and then suddenly go silent, rather than get louder then softer again.  That will often involve some sort of comparator, or some other means to effectively indicate "nothing after this point matters, or will be treated as 'on' time".  It still needs to know there is something being played, and uses an envelope follower to figure that out, but the envelope is treated in different ways than it is with a filter.