hi
I have some really old 78s(early 20s).a friend told me to normalize the records on -1.0db but this seems to low making me need to turn up the volume knob when I play it
back on a cd player…is there a better setting for 78s this old?
lenny
You can go to 0dB, but 1dB louder isn’t much difference.
My bottom-line advice is to normalize to 0dB and adjust the volume at playback time, or use [u]ReplayGain[/u] (or MP3Gain or iTunes Sound Check, etc.) to equalize the volume of all of your files. Note that these volume-matching tools will tend to make your louder files quieter… Since you can’t boost the volume of your quiet-sounding 0dB normalized (maximized) files without clipping.
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0dBFS (zero decibels full scale) is defined/calibrated to how high you can “count” with a given number of bits. You can’t go any higher than that… An analogy is the limit of 999 with 3 decimal digits… You simply cannot go any higher without more digits/bits.
Nothing bad happens when you get close to 0dB, but if you try to go over you’ll get [u]clipping[/u] (distorted flat-topped waves).
Some people worry about “inter-sample overs” and they normalize to -1dB. But, but your DAC should be able to handle any inter-sample overs and IMO this is more of a theoretical issue than an actual audible problem.
Also, if you make an MP3, the wave shape changes (MP3 is lossy compression) and some peaks end-up higher and others lower. If you normalize to 0dB, some MP3 peaks will go above 0dB, So some people like to normalize to -1 or -2dB to leave some headroom in the MP3. But, MP3 is not an integer format and the MP3 itself can go over 0dB without clipping.
Audacity itself uses floating point, so it’s not limited to 0dB. But if you go over 0dB and you export to a “normal” WAV file, your file will be clipped.
Perceived loudness corresponds poorly to peak level. Perceived loudness is more related to the average level and the frequency content.
You can use dynamic compression (unrelated to file compression, such as MP3) to boost the average volume without boosting/clipping the peaks. If you want, you can experiment with Audacity’s Compressor effect. But of course, this alters the dynamic contrast in the recording and the constant loudness can make it boring (like a lot of modern music 
). And since dynamic compression brings-up the quieter sounds, it boosts the background noise in the recording.
It’s a combination of dynamic compression & limiting ([u]Loudness Wars[/u]), the wide frequency range, and musical style that makes modern CDs & MP3s “loud”. Most classical, and many jazz recordings are made with little or no dynamic compression and they tend to be quieter than popular music releases.
hi I just started using wave files instead of mp3 files…thanks for your input…i may need a new cd player too.
lenny