lonely fire

So, anyone who’s recorded/edited music on a computer/digital audio workstation will be familiar with something like this:

Its just a visualization of the audio track you’ve recorded. I’ve always kinda wondered if the shape/outline of the audio given in DAWs was arbitrarily assigned, or agreed upon by some committee, etc. It turns out that it is (duh) a pretty accurate depiction of what sound really looks like (Mr. Obvious strikes again).

Manometric Flames and Phonodieks

Back in the 1860’s, predating Alexander Graham Bell and Thomas Edison, an instrument known as the Manometric Flame was used to visualize sound waves. In a nutshell, a manometer measures pressure; a flame manometer also measures pressure, with variances in the size of the flame it outputs (as a result of changes in the gas supply to the flame) indicating said pressure changes. If one of the walls of the gas chamber for the flame is a diaphragm of sorts, and vibrations of air, resulting from any acoustic instrument, act on that diaphragm in order to cause the pressure changes in the gas leading to the flame, the size of the flame will vary in kind. If you turn out all the lights, rotate a mirror in front of said flame, and take a picture of it, it’ll look like this:

Those particular examples are soundwaves of human speech, not sure what year its from.

The Phonodiek was developed a little later, in the early 20th century. The process is kinda complicated, but through sets of mirrors and lights, it allowed one to actually photograph soundwaves on film. The following examples came from a flute, clarinet, oboe and saxophone, respectively:

Follow this link for more info/better descriptions (and the sources of these pictures).

In the late 1920’s, when sound on film was developed, there were two different systems for it- variable density (basically an optical barcode) and variable area (similar to the DAW audio track above), which is still in use today, and is the template for the audio track that we see in DAWs these days

. How sound can be optically rendered onto film, and subsequently read off of it with light, totally fascinates me. Complete magic, if you ask me.

Here are some schematics of the optical sound recording process. Click on the pictures for a more in-depth explanations:

Here’s a link to a lil’ movie on the history of sound in film.

And did you know that Alexander Graham Bell used a human cadaver in his experiments for the phonautograph (a precursor to the telephone)? This article will tell you a little more about it.

And who can forget Greg Sage? Interesting tidbit about his pre-Wipers days cutting records, and studying the grooves therein. Warning- page loads with sound. Click.

This entry was posted on Thursday, June 14th, 2007 at 2:41 pm and is filed under Sound. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.