jes (05/04/83)
I just had the opportunity to hear the Sony CD player. It's wonderful, as all seem to agree. However, it seemed to me that its great advantage, extended dynamic range, is also something of a disadvantage. That is, if you want to play your recording of the 1812 Overture as background music, you carefully adjust the volume so that the cannon shots will be as loud as possible without drowning out your quiet conversation. But then you might as well ask your next-door neighbor to bang on the wall occasionally, and save your CD player, because you won't hear any of the music other than the cannon shots. So what occurred to me is, what the CD owner needs is a variable audio compressor, preferrably hooked up to his volume control the same way loudness compensation often is. Then the soft part of the music will always be heard at the same level (a one-time adjustment). When the "volume" control is turned down a large amount of compression would be applied so the loud parts of the music wouldn't be much louder (also handy for making cassette recordings) and incresing the "volume" level will decrease the applied compression so the the loud parts will be louder. Rock fans could run this idea in reverse, and set things up so that the loudest parts were always at a constant level (threshold of pain + 3 dB) and then minumum "volume" would be no compression and increasing the "volume" would increase the compression until the soft parts were almost as loud as the loud parts. It might be the case that there is enough dynamic range in the CD so that they could be standardized in loudness. That is, a certain numeric level on the disk could correspond to a fixed loudness level at the ear. Then you could talk about loudness level reproduction ratios. Has anyone thought about this? Do any products exist along these lines? Is it likely? Hint: one of the above paragraphs is intended as a joke. If you aren't sure which one, it's useless to reply.
guy (05/09/83)
In a British car magazine I saw a mention of a Hitachi system which
supposedly compensates for the background noise levels in cars. I'd
have to dredge up the magazine (I am out of town until next week), but
it sounds like it, in effect, decompresses the dynamic range...
Guy Harris
RLG Corporation
{seismo,mcnc,we13,brl-bmd}!rlgvax!guy