Source: starportalF-18 BREAKING THE SOUND BARRIER

Source: leahblainedear textbook authors,
the dude in front of the train has bigger problems than how the doppler effect changes the pitch of the train whistle.
he is standing directly in front of a moving train.
Source: justbeingseriouslysocialsavethesounds.info - “the online ‘museum of endangered sounds’ preserves the endangered and extinct sounds of archaic technology.”
Created by Brendan Chilcutt, the site archives a few sounds that might have you nostalgically playing them over and over again. There’s everything from the sound of dialing a rotary telephone to the sound of a floppy drive chugging away. […] If nothing else, listening to the sound of a screeching modem kicking into high gear will make you eternally grateful for your 24 hour broadband connection, and not having to argue about getting off the Internet so your mother can make a phone call.
(Source: thenextweb, via designboom.com)