Posted by Paul R. Ogushwitz on January 09, 1999 at 07:57:05:
In Reply to: Recording Bell Size posted by Tom Caudron on January 08, 1999 at 15:27:23:
The original purpose of the "recording bell" was ... recording!
In the early days of phonograph recording, the sound was received at the big end of a tapered horn (technically, a square exponential horn) and channeled back to the small end of the horn, where transduction to a mechanical device (the record disk or cylinder) took place. The aperture of the recording horn was often 5 - 15 ft on a side. The musicians would sit in front of the horn and play directly into it. (Perhaps someone knows of a website that has photographs of recording studios of those days.)
For technical reasons, the low frequency sounds were harder to record than the high frequencies with this method. (Listen to a 78 RPM record and you will hear the trumpets, clarinets, and violins prominently; the trombones or other middle voices are muddled; and the bass voices are usually very difficult to hear.) So the challenge was to amplify the bass voice. One method was to turn the tuba bell forward so that it played directly into the recording horn. This had two beneficial results: it made the tuba louder, and it put more of the tuba overtones (harmonics ... partials) into the recording. The forward bell came to be called a "recording" bell.