Hello Tim,
Please, don't take it as personnal offence, it is not at all my goal.
I'm gratefull of your work and advises.
Well, first of all my system may not at all be suitable for testing.
It consists of a Raspberry pi Zero an I2S DAC, a 15W AB Amplifier and a tiny 2" speaker in a 5L box (2 resonnant cavities).
For your recall my Alsa plugin does the following:
Wav File -> Stereo -> Stereo + Mono Mix
Mono Mix -> Low Pass -> Tube Harmoniser -> Overtone
Stereo + distorted Mono -> High Pass -> Mono -> DAC -> Amplifier -> Speaker
That said, I played some wav files that I'm used to listen to on real Hifi systems.
With Spice alone (Wav Mono -> Spice -> DAC), I could hear some kind of reverberation effects that was added to the original file.
Inside my loop effect, it didn't make much, but it was not designed to work that way.
Best regards,
Jean