Reverb comparisons

[Vivek]

I have been working on a modernized clone of that Boston sound machine

After tackling the compressor, chorus, distortion, Cab Sim etc, its time to look at the "Gated Echo" part of the circuitry

Please help me with your comments on the pros and cons on various reverb solutions including

Original MN3011 + MN3007
one PT2399 solution
two PT2399 solution
three PT2399 solution
Belton BTDR 2
Belton BTDR 3
Cool Audio V1000
FV-1 with a standard program
FV-1 with custom code
others

What would you suggest in terms of quality of sound, cost, availability, flexibility ?


PS : How important is that "Gated" bit for the Echo ? It appears to be like some kind of pre-delay so that the Echo unit is not fed any signal for first 40ms from start of note.


Thank you for your inputs !!!!

[EBK]

For what it is worth, the Belton bricks are really just multiple PT2399s, BUT they have a really weird modulation "feature" added.  You can, however disable the modulation by carefully drilling into the brick and destroying a single resistor (credit to diablochris6 over on the Madbean forum for figuring this out).

[Vivek]

Are you referring to an LFO changing the delay times of some of the repeats ?

Is that undesirable ?

I thought the patent mentioned it as an advantageous aspect of their design.

[EBK]

Yeah, it's an LFO wobbly bit.  Some people might like it, but others (myself included) find it quite unnatural sounding.  The way see it, if you are trying to improve a crude model of room reverb, why would you add wobbly walls that don't exist in the real thing?

[ElectricDruid]

I'd say the most important question is "how accurate do you want to be?".

If you're cloning the Rockman "reverb", does it have to sound exactly like the original, or is a good modern reverb a decent substitute?

If you want absolute accuracy and cork-sniffing tone-guru points, you'd have to go for the original chips, with all the problems of getting hold of them that that brings.

If you want an accurate copy, you could use an FV-1 with the delay times set up like the MN3011. I think DigitalLarry's SpinCAD designer included a MN3011 block, so that's not too hard to do - "custom code for dummies", if you like. Or maybe I imagined that, I can't say for sure.

Otherwise, change the code in your FV-1 and try out some of the many other Reverb algorithms there are out there. Perhaps you'll decide that the reverb is best if it's *not* 100% authentic! (the MN3011 was a good try for its era, but...)

Personally, I'd rule out all the multiple PT2399 solutions (and Belton bricks on the same basis) - not similar enough, too complicated, and don't offer compensating advantages.

The CoolAudio V1000 is another possibility for a cheap DSP that would be able to do an accurate clone. I haven't used it, so I don't know how hard it is to get running.

[Vivek]

Thanks Tom!

I do not currently feel that it is necessary to be very authentic to the original "Gated Echo". It appears to me that is was designed to be a "sound thickener" and "Pseudo Stereo Creator" rather than a reverb as we know it today. It appears to me to sound like a small room with absorbent walls.

Initially, We are trying out a Belton brick 2 on the breadboard, to see if we can accept that sound.

We will then decide if we need to try out FV-1 and/ or V1000 too. Digital Larry had replied on an earlier thread that he has a MN3011 block in SpinCAD, and it can easily be edited to Stereo. And maybe we can alter mix, reverb time etc to also allow modern reverb sounds.


I just started to look at V100. At this stage, I dont have enough info on how to program, tools available, sample videos.

It would be nicer if we found a standard factory algorithm that we can accept, since writing DSP code will add to our timescales.

[Ripthorn]

I will add my quad PT2399 reverb project in there. There are 3 stages that are somewhat similar to the Belton architecture, but it has much more flexibility and adjustment for decay time, mode, etc. Now, it's a relatively large circuit, but if cost is a factor, which it was to me, I can build the whole thing with enclosure for less than the cost of a Belton brick alone. https://scientificguitarist.wixsite.com/home/t60-reverberator

I wanted something more "real" sounding than a 1 or 2 chip solution, but Tom's Equinox was my choice for a small practice amp that was space constrained. FV-1 algos can sound great, obviously, but cost is the main reason I haven't done any FV-1 stuff yet. If I do go DSP, I'll probably go Daisy Seed at this point.

Here's the demo of mine with crappy playing (it's my main genre)

[ElectricDruid]

We will then decide if we need to try out FV-1 and/ or V1000 too. Digital Larry had replied on an earlier thread that he has a MN3011 block in SpinCAD, and it can easily be edited to Stereo. And maybe we can alter mix, reverb time etc to also allow modern reverb sounds.

That should do the job then!
Feed the relevant outputs to the Left and Right channels and you're nearly there. The Rockman used a short delay ahead of the reverb (mimicking "early reflections")  so you should add that too - another delay block head of the 3011. Larry's SpinCAD is capable of all this without any actual coding being necessary. Then you upload the the resulting file to the FV-1's connected EEPROM and you're off!

As you say, once you have the hardware up and running (and there are multiple examples of FV-1 delay-based hardware on the web, for example https://www.pedalpcb.com/product/arachnid/) then it's just a question of getting the EEPROM programmed with something you're happy with.