I'm working on putting together a digital reverb circuit using the Alesis AL3201B chip and I'm having some trouble figuring out the best way to blend the dry signal with the wet signal.

The circuit's signal path looks sort of like this:

input==>A/D converter==>reverb chip==>D/A converter==>output

The reverb chip has a schematic in its data sheet that shows a simple blend pot with the dry signal connected on one side, the wet on the other side and the blended output coming off of the wiper. This setup seems overly simple and I expect it would give me a range of 100% dry to 100% wet. The 100% wet option doesn't seem very useful and I'd prefer a level control where I could add the reverb to the dry signal like on an amp.

I've been looking at how other circuits handle this. One example is the way the PT-80 blends it's delay level. I may give this a try but was wondering if anyone had any other suggestions.

simple mixer;
            ___
       dry-|___|-o
            R1   |
                 |
reverb-o          |
      |          |
     .-.    ___  | |\
     | |<--|___|-o-|-\
     | |    R2     |  >--o
     '-'         o-|+/   |
      |          | |/    |
     GND         |       |
                 |  ___  |
                 o-|___|-o
                    R3

 R1=R2=R3 FOR UNITY GAIN

I would actually stay with the wet/dry control because the algorithms were written with that range of blending in mind. Also you might find you like the flanger or chorus/chorused reverbs better at a mix of over 50%.

The mix control there works well because it linearly blends between two opamp outputs with the same impedance. That makes for a nice smooth control.

I know what you mean by the annoyance of the loss of the dry in the mix. You can alter the taper if you use a stereo pot and a resistor from the dry source to the dry wiper with the other end of the resistance element grounded.

Also keep in mind that those algorithms are STEREO.  :wink: Try driving one or both channels with the guitar and listen to each output alone.

If the algorithms are stereo, could you (for instance) drive it with a mono input (ie the same on both channels) and get a stereo output?