Emulating Stepwise Bandpass Filters

[Marc]

Is it possible to use the filter blocks in a stepwise way to emulate the Z-Vex Ooh Wah?

That pedal is essentially a tremolo-wah with 4-, 6-, and 8-step sequenceable bandpass filters.

Here's a demonstration:



I'd be interested in any approximation of the above using existing blocks.

 

[npx]

Put a wah block in your signal chain and attach the control parameter to the sequencer in the Axe Fx.

Not sure if there is currently a randomize feature on the Axe sequencer (not near my unit at the moment), but simulating the regular Ooh Wah mode (up to 32 steps!) should be pretty simple.

 

[fret]

Not sure if there is currently a randomize feature on the Axe sequencer

There isn't but you can simulate a lot of random values in the sequencer and it sounds the same.

Btw OP that video reminding me of one of my favorite vids:
https://www.youtube.com/watch?v=bbrKuhcB7cw

 

[iaresee]

Not too hard to with a filter block and sequencer. Here's an 8-step example:



The patch is here: Axe-Change - Download Preset - Ohh-Wah-Wah - by iaresee

I attached the sequencer to the Frequency parameter in the filter block like so:

And then set up the controller to limit how far it would be able to sweep the parameter. I also set the damp and the curve a bit simply by ear -- holding a chord while the sequence ran and tuning it until it sounded musical to me:

The sequencer I set up semi-randomly kind of sort of...I knew what a cool pattern should look like and went with that:

I went with 8 steps, but you can go all the way up to a whopping 32 steps with the Axe-Fx II which is pretty f'ing sweet!

Scene 2 in this patch does the same thing, but using the wah block -- it's quite a bit more extreme and nasal sounding. Less pulse-like. But still cool. Scene 3 uses the filter block but with the higher gain amp; also very cool sounding.

For tons of synth-type fun kick in the tremolo block! The filter, tremolo and delay are all sync'ed to the tempo of the patch so they work in this cool unison way that gives you this wonderfully bubbly, textured pulse thing. I love doing tightly-sync'ed effects like this -- something I could only do on a computer before the Axe-Fx came along. It lets you play guitar more like a synth but still keep it sounding like a guitar.

 

[Ant Music]

Or you could just control it with an LFO and set it to random and adjust the rate as you like it.

 

[iaresee]

Random definitely does cool things but I find a pattern a little more musical -- it become something that repeats, like a melody, that catches the ear and starts to be part of the overall hook for the song.

 

[npx]

Random definitely does cool things but I find a pattern a little more musical -- it become something that repeats, like a melody, that catches the ear and starts to be part of the overall hook for the song.

I agree.

What would be cool is 2 randomization options. A truly random mode, and a randomize button on the sequencer layout page in Axe Edit for use in generating creative sequence patterns in normal mode.

 

[iaresee]

A random button on the sequencer page, especially one that could be assigned to a CC, would be hella sweet. Will submit feature request!

 

[Ant Music]

Or you could randomly set the values for an uneven amount of steps. That would appear to be random enough.

 

[Marc]

Not too hard to with a filter block and sequencer. Here's an 8-step example:

Excellent post and tutorial. What you've demonstrated sounds far better than the Ooh-Wah.

Btw OP that video reminding me of one of my favorite vids:
https://www.youtube.com/watch?v=bbrKuhcB7cw

I will have to make an attempt at a patch like this! It's wonderful and original.

 

[iaresee]

Excellent post and tutorial. What you've demonstrated sounds far better than the Ooh-Wah.

Why, thank you Marc!

The really excellent part is you're not limited to a filter that was pre-chosen by a pedal manufacturer. In addition to playing with the steps in the sequencer, you can play with all the characteristics of the filter that's being swept. You can widen it (make Q greater) or narrow it, adjust it's peak (use the Gain parameter), change the filter type, etc. If you really want to twist it up a bit, try attaching the Gain and Q values to the envelope filter. So the sequencer controls the centre frequency and how hard you play controls how extreme the notch is. Invert it and you a strong pulse on light playing and little no pulse when you really dig in.

How cool is that?

 

[Snedecor]

A random button on the sequencer page, especially one that could be assigned to a CC, would be hella sweet. Will submit feature request!

In the meantime, you can press enter on the front panel, while in the seq/control page, when one of the "stage x" values is highlighted. It'll randomize all the stages... I've done this by accident a few times . Having it on CC would be cool.

 

[voes]

Iaresse, thanks for the patch, soundfile and explanation. Excellent!