There have been several threads on the topic of these two famous presets and the most interesting information from all of them can be found below.

Posted by rackmeister

Thu Jul 28, 2005 8:46 am

PCM 70 v2.0 Presets:

1.2 Pan Delays

    0   1   2   3   4   5   6   7   8   9
0   100 0   0   0   31  0   -   -   -   Pan Delays
1   0   max max OFF OFF OFF OFF -   -   -
2   0   768 376 0   0   0   0   -   -   -
3   0   0   0   0   0   0   0   -   -   -
4   0   15  15  15  15  15  15  -   -   -
5   0   50L 50R C   C   C   C   -   -   -
6   (Patches OFF)

1.3 Circular Delays

    0   1   2   3   4   5   6   7   8   9
0   100 0   0   42  30  0   -   -   -   Circular Delays
1   0   max max -3  OFF OFF OFF -   -   -
2   0   888 584 292 0   0   0   -   -   -
3   0   0   0   0   0   0   0   -   -   -
4   0   15  15  15  15  15  15  -   -   -
5   0   C   50R 50L C   C   C   -   -   -
6   (Patches OFF)

Notes:
Same delay algorithm, uses (up to) 6 delays (x.1-6)
0.0 Mix Level (%)
0.3 Diffusion (“the magic parameter”)
0.4 Feedback (%)
1.x Levels (dB)
2.x Delay Times (ms)
3.x Low Cut (kHz)
4.x High Cut (kHz)
5.x Pan (50L is full left, C= Center)

Posted by Flukather

Sat May 17, 2008 8:20 pm

Panned Delays:
This is a 2 tap delay, not 2 different delays, dual delays etc or anything like that. Normal 2 tap delay (one left/one right), one set at 376ms and the other at 768ms. No high/low cut, and about 10-12 repeats ( last 2-3 ones are really faint). Yes that is alot, but that’s the way it is. This is the delay that Luke uses as his normal delay, quite loud in level.

There is A TON of unit’s that can do this exact thing, so it’s really not exclusive to the PCM70 at all. You can do this on a G-Force, Axe-FX, other Lexicon units, Eventide stuff etc.

Circular Delays:
This one is a bit more complicated, but it’s not as magic or special as many think, because other units can do this one too.

It’s a 3 tap delay ( so it’s one delay with 3 taps, and NOT 3 individual delays as many, including I, thought in the past ). No high or low cut on this one either.

The first delay is 292ms, damped 3db, and panned to the right
Second one is 584ms, and panned to the left.
Third one is 888ms, and panned to the middle.

The way it’s panned etc, it sounds like the echos cross from one side to the other in a circular manner. If you would record a stereo clip of this preset, and then convert it to mono, the repeats would appear to come in groups of three. The first one (292ms) is damped 3db ( which is like cutting the volume in half), the second one (584ms) is not damped and is 3db louder than the 292ms, and the last one (888ms) is 3db louder than the 584ms.

So each repeat in a group of three gets twice as loud (3db) than the previous one. The reason for the last (888ms) getting twice as loud as the one before (584ms), is because its’ panned to the middle, which means it’s sounding through both left and right, instead of just one. When forcing this to mono, it means that this third (888ms) repeat gets twice as loud as the second (584ms) because the second is only sounding through one speaker.

It has about the same number of repeats as the other one ( around 10), maybe just slightly less. The real magic is the diffusion control. It makes the delays sound fuzzier and fuzzier with each repeats. It basically schmears the high transients in the sound. Some liken it to sounding like a pseudo-bit reducer. This parameter isn’t all that common, but other units can do it, the Axe-FX Ultra being one of them. I seem to remember other Lexicon and some Eventide units have this parameter as well. Basically, if a unit can do a 3 tap delay with diffusion, it can do the Circular Delay thingy just as good as the PCM70s.

You can create something simular by just rolling of the high cut, or adding some drive in the feedback loop if your particular unit allows that. To be honest, if you in a live setting set the level of the delay as low as Luke, you probably ain’t going to be able the difference between the diffusion or some regular high cut. Luke uses this instead of reverb, and has it alot lower then the Panned Delays presets.

Posted by Stradazone

Fri Jan 20, 2012 1:30 am

Circular

Panned

Circular & Panned

They were already recorded when I did this QUEEN thing a couple of months ago I just had to solo the guitar track..it was my first time actually using the PCM70, awesome unit!

Hope this helps

Steve Lukather demonstrating his PCM70 delays.