the best simple delay

Here's a very simple delay system that has a lot of desirable characteristics;  I think it's somewhere between the digital delay and the looper in functionality.  In fact, it might even be your tape delay (I won't be back to the unit for a bit and am dying to see the 2.0 update).

We consider the delay as a circular piece of perfect recording time ("tape") with a regeneration control that goes from, I dunno, -200% to 200%, logarithmically?  with software detents(*) at -100%, 0% and 100%?

Now imagine running this delay at a fixed time, with no inputs, and regen = 100%.  This is your classic "Mike discovers circular buffers and A/D/A" primitive delay.

Let's impose some desirable properties: 

1. steady state: with no knob changes, the output doesn't decay in any direction.  That means that the feedback onto the recording itself is completely unprocessed.
2. deterministic: switching the knobs (with the exception of "regen") might make dramatic changes to the sound, but restoring them to the original position immediately goes back to exactly the original sound.

I hope I've conveyed that this is still in the realm of the "na?ve delay" where you simply have a buffer in memory that you're scanning repeatedly. 

So how is this interesting?  You're stuck on a repeating band of time and all you can do is add to it!

Well, you can slow down or speed up that band of time with a dial (like in the looper).   That gives you a longer, lower-pitched or shorter, higher-pitched loop.

The typical way to thicken the plot is to add time modulation to the playback of the loop.  You can do this in a non-destructive fashion by just "slowing and speeding the tape";  of course, anything you record while you're doing that is "speeded or slowed" respectively, but that comes with the territory.  That needs three dials, depth, speed and shape of time modulation, and a mode control (you need at least to know if your time modulation syncs to your delay…)

This is the classic Super Timeline or any other rackmount delay you had at some point, modulo the not-so-stellar sound at the time.

You still have several knobs left 😀 

Other nice-to-have features would include a reverse mode knob, with regular,  "instant" mode and/or "back and forth" mode.  (instant means click E F G click G F E G F E…) 

Again, there is no fancy DSP above, just straight arithmetic (modulo of course these are complex, delicate systems as I too well know).

 There are other features that might take some real programming (but you might have this code just lying around) – for example, time stretching, where you extend the length of the delay but keep the perceived pitch the same.  

Everyone loves resonant filters….  if you had a clever way to introduce a resonant filter that you could keep near self-excitation, it'd sound great – that's a particularly good sound for guitar solos because the sound sparks at certain frequencies and points without screaming.

But the point is that all I want is this unit of time and some regen and some time modulation – the rest is gravy. 

 Now, why is this musically useful?  

It's not to do with my specific playing style, which can be varied;  it's that the transition from music to chaos is easy to accomplish already and tends to lose the audience's attention, whereas to extract order from apparent chaos is much more impressive and provides a better narrative.

Also, delays that satisfy the two axioms above give you a lot of musical security to make mistakes — you can tweak a knob and then undo it without all these artefacts appearing.

As a soloist who sometimes has to fill long stretches (as I play while other people set up and sometimes…) things like an instant delay/reverse with 0-100% regen is very musically useful.   I can play one lick, play a response with myself, start another one.  (I use a headrush for this) — if I get bored or interrupted, I just crank to 100% regen ("press the repeat button"), add some colour, and then I have some time to think of something else to do.

It's even an exciting trick for a short solo – call, response, call, call and response, call regens for a bit and then crank the delay time down short so the unit screams digitally… always a hit at parties.

The DL-4 does that one well, which is why it's popular.  The TimeFactor could be a much better unit than that (and I'll find out when I've installed the 2.0 update).

Thanks for reading! 

(* — in other words, it should be easy to approach and hit these targets from above or below with the dial, without overshooting them.  You'd actually want a weird sort of "taper" to the control, because you'd want to get very fine control just below and just above +/-100% — you really don't need such fine control around 0% but you do need a way to hit it just on.  Yamaha does a pretty good job of this in my O1v, it's pretty clever and often seems to end on just the number I was aiming for.)