There is a knob to adjust one main parameter in each program and a button that can either select one of two character variations for the effect, like 'warm' or 'clear' for the reverb, or can be used to tap in delay times for delay effects.

Single effects available include four reverb types, delay, pitch, chorus, flanger, phaser, rotary speaker, compressor/limiter and simulations of guitar speaker cabs and condenser mics.Some double effects combine compression with detune or delay and reverb with either chorus, flanger or delay, and there are four programs combining compression and EQ for treating whole mixes.

I found that the reverbs were not as detailed as those on more upmarket units but what do you expect for this price? Used sparingly, however, they were very effective in a mix.All the other effects work well and their adjustable parameters added enough extra tweaking power for some nice variations.Things like the cabinet and mic simulator are useful for tweaking sounds while track laying and the mix programs can add the finishing sheen to stereo mixes.

 Zoom RFX300 Specifications: