For here, everything was slightly abstracted — a sonic hum gave way to hazy mixture of lights as I glanced at various ideas and impressions.

“You’re hearing the hum of the engines, but not only are we dropping, then I’m hearing the engine changing pitch and noise,” Ruedy recalled.

The hum of sewing machines is a constant in parts of Guangzhou, a thriving port on the Pearl River in southern China.

At the checkpoint at Sunset Boulevard, the crowd hummed with anxiety.

Just up the hill, the crackle of flames punctuated the low hum of engines and flowing water.