[chuck-users] Newbie envelope glide confusion

I expected that the following code would give a tone that would glide to a new frequency each second. But i think I might be misunderstanding the sync property because i'm not getting any audible output from this. Can anyone explain where i'm going wrong? Envelope env => SawOsc osc => dac; 3::ms => env.duration; 0 => osc.sync; // (0) sync frequency to input, while(true){ 1::second => now; Std.rand2f(100,300) => env.target; }