initial_value (_latent.signal_latency()),
sample_rate (sr),
period_size (psz),
+ ignored (new PBD::IgnorableControllable()),
/* max 1 second, step by frames, page by msecs */
adjustment (initial_value, 0.0, sample_rate, 1.0, sample_rate / 1000.0f),
bc (adjustment, ignored, sigc::mem_fun (*this, &LatencyGUI::latency_printer)),