Serial or Parallel routing for effects ?

[Vivek]

I'm trying to design a pedal that would have

Delay
Chorus
Reverb

and have stereo outs

It should also be possible to individually switch in/out each effect and there should not be a volume change when an effect is switched in/out. There should be a flexible way to adjust dry/wet ratio.

I see 4 options (But I am sure there might be many that I cannot see)


Option A (Series with same path for dry and wet, like pedals and some rack gear)
Input goes to delay in Mono, output in Mono (Dry + Wet)
Chorus accepts Mono in from delay and has Stereo out with the dry already mixed with the wet at each output (Left D+W, Right D+W)
Reverb accepts the stereo out of the Chorus and outputs an L and R which already have the dry mixed in (Left D+W, Right D+W)

Option B (Series effects but dry mixed in last)
Input goes to delay in Mono, output in Mono (Wet only)
Chorus accepts Mono in wet from Delay, and produces Stereo outs which are 100% wet (Stereo Wet only)
Reverb accepts the Stereo wet out of the Chorus and outputs stereo outs which are 100% wet (Stereo Wet only)

finally, the Dry signal is then mixed with the 100% wets from the Reverb to give Left Dry + Wet, Right Dry + Wet

Option C (Parallel effects, with dry mixed separately)
Input goes to delay in Mono, output in Stereo (Stereo Wet only)
Input also in parallel goes to Chorus in Mono, output in Stereo (Stereo Wet only)
Input also in parallel goes to Reverb in Mono, output in Stereo (Stereo Wet only)

finally, the Dry signal is then mixed with the 100% wets outs from the Delay, Chorus and Reverb, to give Left Dry + Wets, Right Dry + Wets.

Option C1 (Delay feeds Parallel effects, with dry mixed separately)
Input goes to delay in Mono, output in Mono (Mono Dry + Wet)
Mono delay out goes to Chorus in Mono, output in Stereo (Stereo Wet only)
Mono delay out also goes in parallel to Reverb in Mono, output in Stereo (Stereo Wet only)

finally, more Dry signal is then mixed with the 100% wets outs from the Chorus and Reverb, to give Left Dry + Wets, Right Dry + Wets.

I need your help with :

A) Please comment on the usability of the sound in all the above combinations

B) Are there other better ways of placing the effects besides the options above ?

C) Which setup would you use personally and why ?

Thanks !!!

[ElectricDruid]

I don't think only mixing the dry in at the very end is going to work, Vivek. Or at least, it won't give the same effect as mixing it in at each stage.

For example, think about chorus into delay. If the chorus has no dry signal mixed with it, it's not a chorus, it's a vibrato. So then you're feeding the delay with a vibrato signal not a chorus signal, so the output isn't what it would be if it was fed from a chorus. Adding a bit of dry back in later doesn't fix that.

[Ripthorn]

Tom's concern would be my primary concern as well. To hear how it sounds for each case, I would use a DAW and a few busses, each with a single effect and then monitor the master buss. That would let you hear each effect in parallel. I think most people are most comfortable with series just because it's a very simple, logical chain to understand. Parallel interactions are much more complicated. I work in the mixed signal processing semiconductor field and we have a part that does parallel signal processing and it is much more complex to dial in the end effect than in series. Parallel can have some advantages, such as latency or isolation of specific characteristics, but in my experience, it tends to be relatively low reward for plenty of risk.

[Vivek]

Some famous headphone amps of the 80s had following signal flow

1. Dry goes X% to L mixer, Y% to R mixer

2. Dry also goes to mono chorus in parallel
mono 100% wet output of chorus goes  Y% to L mixer, X% to R mixer

3. Dry also goes to stereo reverb in parallel
100% wet L from reverb goes to L mixer, mixed about X%
100% wet R from reverb goes to R mixer, mixed about X%

[FiveseveN]

But the 80s are long gone .

[Vivek]

Yet, the sounds of the 80s are coveted till today.

There must have been something good about their order of effects.

[amptramp]

There are some topological transformations that can give the effect of mixing dry with wet signal.  For example, the Tube Screamer is popular because there is always a gain that never goes below 1 in the clipping stage for the incoming signal due to the non-inverting signal having a gain of 1 even during clipping.  Similarly, if you have an antiparallel diode=to=ground distortion like a DOD 250, putting a resistor in series with the diodes is equivalent to adding dry signal.

You don't always have to establish a parallel path in order to add dry signal.

[Vivek]

Thanks Amptramp,

I agree with you re distortion stages.

I need guidance for delay, chorus and reverb.