The stereo_amp 'amplifies' the two input signals (in_left and in_right). It can
also shape them via in_amp_eg (hint: connect to adsr out_output).

right_level and left_level should be set to 1.0 for the input signals to remain
as they are. 0.5 will halve their loudness, and 2.0 will double it. By setting
clip_level to 1.0 the output from out_left and out_right will be forced within
the range -1.0 to +1.0 - which is generally how you want it - with higher
amplitudes sheered off.

If you wish to use in_amp_mod for velocity changes of 'notes' then you will
certainly wish to use the sequencer module's out_velocity_ramp so that clicks
(as velocity changes) are avoided. The adsr might be better used for controlling
velocity levels.

See also: mono_amp adsr sequencer
