Since the instrument jacks 2 through 4 are designed for line-level inputs, such as a bass guitar, keyboard or drum machine, the sensitivity of these jacks is lower than for Channel 1. The EFF level control is the return adjustment for the effects loop and the internal DSP processor on the S400D model. Send and return jacks are provided for an external effects processor. The DSP has a 16 detent Select knob that lets you choose the effect you want. The channel effects send and master effects level control determine the amount of your effects.
Echo effects are delays with a little plate reverb added.
Reverb is offered along with echo. There's also Chorus 1 with reverb, Chorus 2 with reverb and Chorus 3 with reverb. Take your choice. A black textured vinyl covering with black metal corner protectors and an expanded metal grille provide a tough package. Dispersion angles are 90 degrees horizontal and 45 degrees vertical.