How was Edison’s phonograph different from a mechanical music box?


Follow-up: Which device was able to produce a more accurate sound?

In: Engineering

The music box plays pure tone notes according to a musical score. The phonograph records analog sound.

If you have an Edison recording of a music box, the music box itself is more accurate sound.

In all other cases, the recording is better. Edison recorded human singers, something no music box can reproduce.

The phonograph recorded and reduced actual sound waves. Maybe not really well, but that’s what it did. On the other hand, a music box is basically a musical instrument, it sounds like a music box or other similar instruments. So I guess if you’re trying to reproduce any general sound, like a voice singing, the phonograph of course does a better job. In a head to head competition, with different kinds of sounds, the only time the music box would come out ahead is when playing sounds that are similar to a music box. Another difference unrelated to sound quality is that the music box needs to be essentially programmed to play a particular song, unlike the phonograph which uses a recording.

A music box can play notes, but not audio. You can’t record into a music box, and a music box can’t play a voice, or a violin, or a trumpet. It’s an instrument that plays a pre-set melody, not a means of storing audio information.

A phonograph, on the other hand, can record and play back audio. You can record a voice, a violin, a trumpet, or any other sound.

If your sole objective is to store a short melody that can be listened to, and factors other than the notes themselves are irrelevant (timbre, volume, etc), a music box may be more accurate. If you want to store a piece of audio (such as a voice), that cannot be represented adequately/at all with a sequence of notes, a phonograph is infinitely more accurate.

A mechanical music box has a “comb” of metal tines that make a sound when plucked. The tines are made to be a particular length so that each makes a particular note when plucked. You can think of the tines as being like piano strings that play a note when the key is struck. But the music box would only have about 10 tines compared to 88 keys on a piano.

The music box then had a metal disc with bumps on it that would pluck the metal tine as it went around. The arrangement of the bumps determined which note was played and when – so it determined what song the music box played.

So a music box could play about 10 different notes.

Edison’s phonograph recorded as bumps the sounds that a microphone heard. It could then read those bumps and play back the same sound. It was not limited to certain notes. So it could play voices, songs, or other sounds.