The Catalinbread Zero Point is one of the most interesting effects that we have seen in a long time. Through-Zero flanging is a really interesting effect that was originally achieved by setting up two tape reels of the same track and manually slowing one down to the point at which they cancel each other out. What makes this emulation of that effect really interesting however is just how you control it.
With the original effect the only control you had was your thumb which was manually slowing down the tape. This pedal wants to bring back that same type of control to your pedalboard so there are only two switches on the Zero Point. One which turns the effect on and off, when turned on you do get a subtle comb filter effect but it is the second switch where the magic lies. When you push this momentary switch down one of the 'tape machines' starts to slow down to give you a fantastic manually controlled flange. The time slowly moves as you hold down the control and when you release it starts to play catch up with the other 'machine' to get back to the more subtle comb filter effect.
Inverted or Positive Flange
As default this pedal starts up in the more dramatic inverted mode which is what allows you to get that really cool phase cancellation effect. However if that is just a bit too much you can instead opt for a more subtle effect by holding down the momentary switch while turning the effect on. This makes the pedal much more traditional tonally and lets you get effects that would fit into a wider range of situations.
Here's what Catalinbread say about the Zero Point Flanger
The Zero Point Flanger is the most direct analogy to studio tape flanging that anybody has come up with. It is a REAL TIME effect not a typical modulation effect. That is to say, unlike all other pedal flangers, there is no LFO that presents a predictable up and down swooshing sound, the trite flanger effect that died in the 80s. Thus there is no need for extraneous knobs or switches. It is a straight-foward pedal that has only one powerful control that behaves like pressing and holding your thumb on tape flange.
When the Zero Point is engaged two delay lines are turned on, subtly modulating against the other simulating the comb filtering effect akin to the playback of two tape machines. Pressing and holding the "Flange Push-Button" causes one of the delay lines to slowly shift time toward the other delay line, up to the point that your signal begins to cancel out, THE ZERO POINT! Release the Flange Push-Button and the delay line begins to automatically fall again. The result is the whispy subtractive 'thru-zero' sound that creates a sense of space and mystery. An effect that up until now we've only heard on records. It behaves just like manually advancing the take up reel and pressing your thumb on the supply reel to slow the program down.
The Zero Point Flanger automatically powers up in the inverted phase mode, resulting in a more dramatic subtractive flange effect. If you press and hold the Flange Push-Button while powering up the Zero Point you enter the positive phase mode which because it sums the two delay lines, never cancels out. This mode is a bit less dramatic than the subtractive mode but still a very tape like analogy. There are merits to both modes, ultimately it is best left up to personal preference.