Difference between stereo reverb and dual mono reverbs?

[famous beagle]

So I saw this cool video about creating a great-sounding spring reverb using nothing more than an Accutronics reverb tank, a headphone amp, and a direct box:

https://www.youtube.com/watch?v=iWwEnzUJ6TI

The tank costs $22.95, and he mentions that price in the video but also mentions $44 if you want to do a stereo version. I was on board and ready to order the parts, and then I started thinking: You'd just be sending a mono signal (combined instruments from the FX send) to the headphone amp, splitting that mono signal, running each through its own reverb tank, and then coming back in to the returns (via direct boxes).

So .... is this really a stereo reverb? Because it seems to me that it's actually just dual mono.

And if it's not a stereo reverb, what is a stereo reverb unit doing to the original mono signal to make it stereo anyway? Is it splitting the signal and treating each side different with regard to delays/EQ/???

Hope this makes sense.

Thanks

Edit: Now that I think about it, I suppose that the two springs would never react exactly the same to the signal since you're dealing with a physical, vibrating spring. So the reverb generated by each side would be different -- at least slightly. But it still brings me back to the question of what exactly a stereo reverb (digital, let's say) is doing to create the stereo signal.

 

[mixsit]

Edit: Now that I think about it, I suppose that the two springs would never react exactly the same to the signal since you're dealing with a physical, vibrating spring. So the reverb generated by each side would be different -- at least slightly. But it still brings me back to the question of what exactly a stereo reverb (digital, let's say) is doing to create the stereo signal.

That's sort of typical for a lot of verbs- you send one sig into a L/R processor, 'stereo sound effect comes out.
A true stereo verb if you like to call it that has (or can have) a left' and right' ins, and they can be variations on left stays mostly left etc, or Aether for example you can decide how much they 'cross pollinate.
You could do that with the pair of springs, and a mixer.

 

[Robus]

That's true of most of what we do witb reverb. How often do you send a stereo source through stereo reverb? I don't much. Most of my tracks are mono.

 

[ido1957]

That's true of most of what we do witb reverb. How often do you send a stereo source through stereo reverb? I don't much. Most of my tracks are mono.

I pan rhythm guitars and backup vocals L/R and pan the reverb send on each the same amount.

 

[Robus]

Yeah, I thought of that after I posted. I do actually put guitars, drums, and backup vocals in folders and them to the reverb bus as stereo sub mixes.

Beagle, I'll bet that reverb unit is going to sound pretty cool. I love spring reverb, goes with my fondness for Fender amps. If you could set up your electrics guitars as a stereo mix and send them to the external reverb unit, it would be awesome. Post a track if you get it running. I would love to use more external gear, but I don't have enough sends and returns on my current A/D.

 

[famous beagle]

That's sort of typical for a lot of verbs- you send one sig into a L/R processor, 'stereo sound effect comes out.
A true stereo verb if you like to call it that has (or can have) a left' and right' ins, and they can be variations on left stays mostly left etc, or Aether for example you can decide how much they 'cross pollinate.
You could do that with the pair of springs, and a mixer.

Right, but what does the reverb unit do to make it a stereo signal when it's a single input? How does it make the left and right sides different so it's not just dual mono?

 

[ido1957]

I have no idea but my old Lexicon PCM 80 does it too. Mono in and stereo out.
It actually sounds pretty cool on headphones.

 

[mixsit]

Right, but what does the reverb unit do to make it a stereo signal when it's a single input? How does it make the left and right sides different so it's not just dual mono?

Hmm. I not sure what you're missing in it.. Maybe it's the getting too into the 'dual mono term. Yes it means a pair of discreet paths, and that would be the case with a pair of springs. But unlike two simply mono verbs like that, there's no left/right mixing (until you add that in in some way). On one extreme of it you'd have two hard L/R outputs, no cross/mixing. On the other you can have the single input and all sorts of variations on a stereo effect spread. On something like Aether that can work from one or both sends, the possible variations from 'discreet input panned directed L/R effect imaging, to.. what ever.. is staggering.
(That's to say,, for me it's a fairly intimidating plug. But go read it. It'd be a good primer.

 

[mixsit]

I have no idea but my old Lexicon PCM 80 does it too. Mono in and stereo out.
It actually sounds pretty cool on headphones.

And.. you have pannable delay voices, feeding into or around and back into the verb engine..
The flexibility in that box.. was sort of the first things I noticed missing in the Native bundle patches.

 

[famous beagle]

Hmm. I not sure what you're missing in it.. Maybe it's the getting too into the 'dual mono term. Yes it means a pair of discreet paths, and that would be the case with a pair of springs. But unlike two simply mono verbs like that, there's no left/right mixing (until you add that in in some way). On one extreme of it you'd have two hard L/R outputs, no cross/mixing. On the other you can have the single input and all sorts of variations on a stereo effect spread. On something like Aether that can work from one or both sends, the possible variations from 'discreet input panned directed L/R effect imaging, to.. what ever.. is staggering.
(That's to say,, for me it's a fairly intimidating plug. But go read it. It'd be a good primer.

Hmmm ... thanks for the info ... I guess I'm still not stating my question well enough. Let me try this:

Scenario 1: Let's say you send guitar, keys and drums out FX send 1 (mono send) into the left channel of a Lexicon PCM reverb unit. You then come out both channels of the Lexicon and into FX return 1 L/R jacks. You pan those returns hard left and right.

Scenario 2: You send guitar, keys and drums out FX send 1 (mono send) into the left channel of a Lexicon PCM reverb unit. You then come out the L channel of the Lexicon and into the FX return 1 L jack. You pan that return down the middle.

Scenario 3: You send guitar, keys and drums out FX send 1 (mono send) into the left channel of a Lexicon PCM reverb unit. You then come out the L and R channels of the Lexicon and use a Y-cord to join the combine the signals and plug that into the FX return 1 L jack. You pan that return down the middle.

Would these scenarios sound different? If so, how and why?

 

[Farview]

Scenario 2 and 3 would sound the same if the Lexicon sums to the left channel when nothing is plugged into the right.

The first one would, of course, be in stereo because the "rooms" they designed are not perfectly semetrical.

If the pcm doesn't sum the outputs when nothing is plugged into the right output, 2 and 3 would not sound the same. 3 would probably be denser.