Spectrograph: Listen & Download Spectrograph .mp3 Error! Change your browser, please! ⇓ Download Conveyor, conveyor belt ⚠ Hydraulic activator ⚠ Postal sorting line ⚠ Car factory ⚠ Electric generator (hum) ⚠ Power station generator ⚠ Signal for lunch at the factory ⚠ Newspaper press ⚠ Working machine engine ⚠ Compressor industry ⚠ Power station turbine ⚠ Vibrosieve at the factory ⚠ ★★★★★