Hello,

I'm currently working on creating a 'more-than-usual' Phaser patch.

Basically, I would like to implement a few cool features - one of them being the ability to have the amount of phaser effect proportional to the amount of incoming (dry) signal so that, for example, the swooshing effect fades out as the signal does.

Just wondering if anyone had any tips for this?

Many thanks,
esap

A phaser effect happens when you mix the original signal with a series of allpass filtered versions of the same. The effect is strongest with a 50% mix of original and allpass. You could try env~ to control the mix amount. I'm not sure it would do what you want but it should do something.

Thankyou - I shall experiment with that.

Another feature I was thinking of trying to implement, but am having difficulty with; was having different waveforms (si/squ/saw/tri) selectable by the patch, with control key switching (ascii keys) - which should phase 'differently'. The issue I'm having there is how to call up the different waveforms to select between?

Well, that depends on how you are implementing them. Are they all stored in tables? If so, then switching them is as simple as using the [set( message for [tabread~]. If not, best way is probably to have each waveform implementation in its own subpatch with [switch~] inside to turn them on and off.

Ah thanks for the suggestion. I've managed to encapsulate the waveform objects into their respective sub-patches, but I'm not sure how I can set it up so that the incoming waveform works with switch~ to trigger each type?

I usually do something like this:

[r $0-waveform]
|
[== 1]
|
[switch~]

So, each waveform has a number associated with it (convenient for selecting with [vradio]). In the above, when waveform 1 is selected the [switch~] turns on; when any other waveform is selected, it turns off.

One neat thing that's typically ignored in phase shifters is that each allpass stage can be a different frequency, or even modulated independently. I haven't thought of a way to control this that's both flexible and usable, but it could be an interesting thing to play with...

And also if you're using a long chain of allpasses, you can mix the dry and phase shifted signals at various intermediate points in the chain, which lets you superimpose lots of notches that can be independently controlled. I've only played with this briefly, but it seems like a nice addition to the usual effect...

Also feedback is great but you need to use a block size of 1. And you can put the allpasses in series with modulated delays to make a sort of hybrid phaser/flanger thing.

I tried to make a super phaser/flanger thing at some point, but it got really overcomplicated.

Hi,
Thanks for the feedback. I've been experimenting and have managed to create a good setup with the patch so far. However, I keep receiving these errors:

'warning: phase2: multiply defined
warning: phase1: multiply defined
warning: output: multiply defined'

when trying to send audio. I have a catch~ receiving the signal okay, but when I'm sending the signal on to the 'pd allpass' stages, these errors seem to crop up.
Is there a way to fix this?

Make sure you are using [throw~] and [catch~] correctly. If you want multiple signals to go to one spot, use [throw~] and [catch~]. You can only have one instance of [catch~ phase2], but as many [throw~ phase2]s as you want. If you want one signal to go to many places, use [send~] and [receive~], which works the opposite way.

Ah great - that seems to have corrected the problem!

My last issue is with implementing a feature. I'm attempting to have the amount of effect be dependent upon the amplitude of the incoming signal (so that the swooshy effect fades away as the sound does.) I've tried routing the delay output back into the first allpass stage but that doesn't seem to have had any affect.

I'm just wondering how I'd go about this?

I believe you want to control the amount of the all-passed signal that is mixed with the dry signal to do that.

I've attached the patch below as I think it'd be hard to explain further..

The issue that seems to be recurring is that when I try and mix the dry and allpassed signal together, they don't seem to sit, which is making it problematic to try and have the wet (phased signal) mix level dependent on the dry level. The allpass stage now also seems to be distorting its signal for some reason too?

esap, how can I get the volume of the swooshing sound up? I created a new thread asking this... maybe you can help me there: http://puredata.hurleur.com/viewtopic.php?pid=37763#p37763