Snow White speed mod

[Mark Hammer]

Yes...just not easily.  It's more than simply moving a tap point (as might be selecting LP vs BP), or tweaking a cap or resistance value.

[chemosis]

 how can i make the sweep stronger but also have the original sweep. and how can i get a little more resonance.   and youve prob heard this alot but thanks alot mark

[Mark Hammer]

Well it's possible, but as I constantly blather on about, downward sweep is not simply the "opposite" of upward sweep.  In the first place, we tend to hear downward sweep a little differently, so simply covering the same start and end points in reverse is unlikely to be pleasing.  Stephen Giles came up with a brilliant and simple mod for the MXR Envelope Filter to reverse the sweep direction.  But if you've built it, you'll know it doesn't sound as nice as the upward sweep, and requires a few tweaks to sound sweet.  As well, with HP filtering, the "starting" point has to be lower down than the maximum upward sweep.

Think of the following scenario.  Everything below 5khz is absent when you start out, but gets included as the sweep continues.  Pretty thin-sounding, eh?  Going upwards, a LP sweep that rolls off content above, say, 500hz, and then lets more in as it sweep upwards to 5khz, will have the same amount of "meat" to it across the sweep.  A BP upwards sweep with a center-frequency of 500hz will have "meat" for a portion of its sweep, but get thinner towards the high point of the sweep, re-introducing meat as it settles back down.  A HP downward sweep starts out thin, acquires more meat, and then loses it as the sweep returns to its starting point.  Moreover, if it sweeps too fast, that rapid introduction of lows and mids will sound like a door slamming.

So, to make a downward sweep sound good for HP, you'll need to adjust its starting point and adjust the sweep rate.  And that, while feasible, starts to get complicated.

[chemosis]

thanks. ok what about a little more resonance. would increasing the resonance pot work or do i need to add a pot in place of the feedback resistor on the op amp??

[chemosis]

ok last question .that was probably kinda a stupid question. just increase the resonance pot for more resonance right?? then would i need a gain pot or output pot because of the volume spike that comes with more resonance and if so how do i do a gain or volue pot mod??