phil@mips.COM (Phil Arellano) (09/04/88)
In article <44000023@pyr1.cs.ucl.ac.uk> william@pyr1.cs.ucl.ac.uk writes: > >Something I would like to see marketted is a device that you can >plug into the speaker circuit that will normalise the output volume. >If I am watching a film late at night, nothing annoys me more than >having to constantly tweek the volume down when ads and screams come >on, and then having to bump it up to hear all the low volume whispering >that goes on the rest of the time. A circuit already exists to fit the bill. It is called an audio compression circuit. Amateur radio operators use these compression circiuts to condition the audio from microphones. Radios and TVs also use a form of compression in the AGC circuits. These circuits serve to boost low level signals without amplifying the already high level signals. Most compresssion circuits also have contain a final output gain control to limit the maximum output level. However, remember that compression means 'reduce dynamic range'. This would cause quiet passages of your source material to become amplified (read noisy) as well as de-emphasizing the louder sounds. I haven't checked to see if anyone sells a compression box to plug into a stereo system, let alone a television, but such circuit designs can be found in many electronc cookbooks. Now that you know what to look for, happy hunting!-- phil@mips.com UUCP: {decvax,ucbvax,ihnp4,hplabs,sun,ames,prls}!decwrl!mips!phil USPS: MIPS Computer Systems, 930 Arques, Sunnyvale, CA 94086, (408) 991-0358
kos@demon.siemens.com (Stephen Kosonocky) (09/06/88)
Speaking of audio compressors, does anyone out there have any schematics or references for one. I'm interested in making one for taping CD's for the car. Please post or E-mail any responses.