Sawtooth waveform. 55 Hz frequency Created with Audacity
Arp 2600 Triangle wave @ 220hz.
Sine wave. 220 Hz frequency Created with Audacity
Square wave sample at 220Hz
I am unlocking keyed padlock, inserting key, then turning it and removing 'n' bar.
Unlocking my back door, opening it then going outside and closing it again.
A mono till or cash register without a bell. Made with parts of an mp3 recording of a vintage typewriter ...
Inserting key into lock and unlocking.
Mono recording of antique cash register sounds made with Sennheiser MKH 40.