Sorry, this might turn into a long post…
When you normalized, what settings did you use? And, what are you trying to accomplish by normalizing?
…The strange thing is, if you normalized I assume you normalized to 0dB or -1dB and you should be close to 0dB (even after MP3 compression).
I ran it through Amplify, the panel appeared and in the top part, Amplification (dB), it showed 7.698 (no negative sign so I assume positive).
Well, that means your current peak is -7.9dB and that’s plenty of headroom and I’m not sure why your playback meters are going “into the red”…
if your peaks are -7.9dB (or any negative value) you don’t have a problem!
Below it, New Peak Amplitude (dB), it showed -0.0 .
Yes, that’s normal. Amplify defaults to whatever gain (or attenuation) is need for 0dB peaks. So for example, if you run it twice in a row you’ll see 0dB of amplification (no change) and 0dB for new peak amplitude. (So nothing happens the second time if you again accept the defaults.)
and that’s I pressed ‘OK’ and what I had thought was within parameters
Since you are “only” peaking at 0dB and you’re not clipping, amplification won’t change the wave shape or cause distortion.
was now covered with dark blue from top to bottom. I may be wrong but I don’t think it should look like that.
Some modern CDs are "brick wall limited’ and they look like a solid blue block. But 8dB of gain is quite a bit louder and it might be “too loud” compared to other albums/tracks. And, the reason for the brick-wall limiting is (usually) to “make it loud”, so they don’t usually leave any headroom… It’s usually slammed right-up to 0dB.
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More about MP3s…
When you open an MP3 in Audacity it gets decompressed. If you re-export to MP3 again you are going through another generation of lossy compression. And the “damage” does accumulate. So if you are going to change anything, it’s best to go-back and start-again with the uncompressed original. Then compress ONCE as the last step.
Since you can’t predict the peak levels for the MP3 copy, keeping the peaks at (or below, 0dB) is a 2 or 3-step process. But again, your particular file does NOT have this problem…
Personally, I don’t worry about the MP3 going slightly-over 0dB, but some people do. I don’t hear any distortion from that and I’ve already accepted the fact that MP3s are lossy and I don’t expect “mathematical perfection” (although it can often sound exactly like the original)
But if you want to always avoid clipping, the easiest solution is to normalize to -1 or -1.5dB. Then after exporting to MP3, open the MP3 and run Amplify to check the peaks (as above). Usually it will be OK, but if not re-open the origin uncompressed file, normalize to a lower level this time and re-export to MP3, and throw-away the 1st MP3. (And, you can calculate the normalization level to get it just-right.)
Or if you always want it “perfectly normalized” to 0dB you can Amplify once to 0dB making note of the default change. Export to MP3, re-load the MP3 and note the “error”. Re-open the uncompressed original, run Amplify again but this time change the default to take the “error” into account.
