This is long overdue--if any FX processor needs a thread like this, it's this one! The DD500 and Nemesis threads really brought together a LOT of great info together, and I'm hoping to do the same with this thread. These units need it even more, because this is one where you have to know the "tips and tricks" just to get some of these effects to work in the first place! I've been programming a PCM80 and a Pitch Card for about two years now, and it's easily been the most rewarding experience I've had in the last 8 or 9 years that I've been into effects. It's really changed the way I've thought about a lot of things, and helped me save a LOT of money too (since I haven't had to go out and just buy everything I wanted--oftentimes, I found out that I could just program it here!). First off, a basic rundown of what these are, for those who aren't familiar with them... These are not 100% dedicated reverb units (though they are often confused with the Lexicon PCM90 and PCM91, which came out around the same time, and are dedicated reverbs)...nor are they your "typical" multi-FX units, ones that might sacrifice processing power to run FX and reverb under one roof...what these are--and what makes them so special--are dedicated reverb AND dedicated FX under one roof, using dedicated chips for both! Nothing is compromised, ever--if you see a Chamber verb in one algorithm that you like, then it's going to be the exact same Chamber in every algorithm where a Chamber appears (i.e. you'll never get a more "limited" version of Chamber in different algorithms--the parameters, power, and sound quality are always the same). Likewise, the FX never share resources with the reverbs either, so your power is always optimized there as well. The power of the reverbs in these things are well-attested (and I will certainly go into those here too), but I really want to spend some more time discussing the FX portion of this, since--along with its of LFOs, envelopes, and modular synth-like patching system--that's where most of the "mystery" lies with these units. Nothing is "ready-made" here (there's no "Chorus" or "Flanger" block anywhere), so unless you're lucky enough to come across a factory preset that has the effects you want, you'll have to know how to build it in the algorithms--and that is what I'm hoping to shed some light on here, more than anything else! Now, following up on the Vintage Rack Units thread and, in particular, this post, I'm going to break down all the different delays that go into the Chorus+Rvb algorithm--one of the best algorithms for guitarists to be found in this box, and also, possibly the most-optimized one for emulating analog effects In the Vintage Rack thread, I mentioned that these delays could all be synced to tap tempo... V1 Delay V2 Delay V3 Delay V4 Delay V5 Delay V6 Delay RefDelayL RefDelayR EkoDelayL EkoDelayR Reverb Predelay And here's how they all fit together in the Chorus+Rvb algorithm: That shows you where all the "Voice Delays" are, which are the main modulated delays--it's basically two groups of 3-tap delays (if you've ever used "Circular Delays"--that's a 3-tap delay, with the taps panned L - R - C as you go from shorter to longer), with feedback on EACH delay (very rare! on most multitap delays, only one of the taps will have feedback). That still leaves the RefDelays, the EkoDelays, and the Reverb Predelay, which can all be found here, inside the "reverb shell": Now here's one cool thing about Lexicons--the reverb has extra delays! Not just "predelay"--there's also the Reflection Delays (RefDlys) and the Echo Delays (EkoDlys), which you can utilitize with or without the reverb...so these really come in handy in the course of programming just delay-centric patches too--or even being the "main delays" if you've used up all your Voice delays doing other things (which can sometimes happen, especially if you're building a 6-voice chorus/flanger). Plates, Chambers, and Infinite verb types especially have the most to offer in this category, so anytime you see an algorithm with one of those, think to yourself that you just got 4 or 5 "bonus delays" The EkoDelays are particularly nice, because they have diffusion ("smear") that re-circulates in the feedback path--one of the "magic" ingredients you don't find in a lot of delay units...so if you don't always find what you're looking for in the Voice delays, you might find it here in the reverb shell delays. Now, about the modulation... Each of the 6 voice delays has its own modulation rate & depth, so, much like the Rocktron Intellifex, or the Yamaha UD-Stomp/Magicstomp units, you can create some truly spectacular chorus, modulated delays, and combinations of both that even interact in ways that would not be possible to do with separate chorus and mod delay pedals. There are two "groups" of these--one with V1/V2/V3 and one with V4/V5/V6--and in each group, the delays are in parallel, but there is common feedback between each trio of delays, and each feedback can be positive or negative phase (great for flangers!). With very short delay times, multi-voice stereo flangers can easily be created, and with longer times (slapback and a little beyond), you can make clusters of echoes that border on modulated reverbs when all 3 feedbacks are engaged (very nice for swells too!)...all the while, all 3 voices can have different modulation going, so as everything gets fed back, all 3 delays get fed back into the line and then get "re-animated" again by all 3 modulators...so things can get very dense, very quickly! And that's just with one side--there's a whole 'nother one with all the same elements you can use, to either add to what the first side is doing, or By the way, I should mention that "side" here just means placement in the drawing--each voice delay has its own panning control, so you are free to pan any delay, anywhere in the stereo spectrum you want on either "side" of that drawing (or even pan it around in realtime with LFOs! I will definitely add more about this later). Now, the Voice delays are fairly easy to set up--you can easily set up simple stereo echoes by using one delay from each group (V1 & V4, let's say), turning up the feedback on just those delays, add a little modulation, tap tempo, high-cut, etc....fairly straightforward, and it just "works"; the Shell delays are a little bit different, though... If you look up at the drawing, you'll see that the RefDelays don't have their own feedback, but their signal path does go all the way to the output...and the EkoDelays do have feedback, but their signal doesn't go all the way to the output--reason is, the EkoDelays go through the RefDelays, so if you want to have just a "typical" delay sound out of these, all you have to do is set the RefDelay and the EkoDelay to the same delay time (or tap tempo rhythmic subdivision), turn both of their levels up, and then they will act like one "normal" delay. The EkoDelays also do something special here that the Voice delays don't in this algorithm, which is pass through the Diffusion on every delay repeat, so it will "smear" it over a larger amount of time as it feeds back, in a way that the time display won't fully account for (just something to be aware of when making rhythmic delays--sometimes, if you use too much diffusion, it can throw the rhythm off!) Now that is one extra step to go through just to set up a simple delay, but the nice thing here is that the RefDelay and the EkoDelay don't have to be the same time--and when you get into the different tap tempo rhythmic subdivisions, this is really nice, because you can really get some crazy patterns going when all 4 (RefL, RefR, EkoL, EkoR) are different And that's just the reverb shell delays! You can mix in as many voice delays as you want and create huge, intricate patterns, even ones that can be as dense as reverbs...the sky's the limit! One important distinction between the Shell delays and the Voice delays: while the Voice delays can be panned anywhere in the stereo field, the Ref & EkoDelays are by default panned "L" or "R," depending on which one you're using (there is kind of a way around this, but it involves some "tricks" which I will get to later ).