Hi,

MP3Gain tells me, that 90% of my LAME --preset-standard encoded MP3s have clipings.

Well, this doesn't sound good to me. There are two possibilities:
1. LAME --preset-standard produces MP3s that are not optimal
2. MP3Gain is a little paranoid, and I can ignore this clipping-info.

what's true?

BTW: MP3Gain tells me that most of my MP3's are too loud (-4.5 to -9.0 db). Does this makes sense.

I'm not an expert but I think it's something like this:

The original is very close to clip, i.e have samples close to 32767. As an example lets say some samples are 32766. Even though lame aps is excellent, it's still a lossy format. So when encoded and then decoded the original sample of 32766 might have turned into 32761 (-5) or 32771 (+5). The last one would of course be clipped to 32767.

The solution would then be to scale down the volume of the entire track, but that would mean moving further away from the original, which is not the intention of lame aps. lame aps is aiming at being as close to the original as possible, and if you scale down you would be doing the opposite.

Now, I think these small clippings are not really a problem unless you have really excellent ears. If you really want to avoid this, use MP3Gain with the noclip gain function. I think there is a FAQ or user guide for MP3Gain somewhere in this forum. Try search.

MP3Gain tells you that your tracks are 4.5 to 9.0 dB above the reference level that you can set for your self. (Input box above the track list). Default is 89 dB which is a bit lower than most music today. 89 is pre-chosen as a good value to assure that most tracks don't clip.

I wouldn't worry about mp3gain "changing the file from the original" in any qualitative sense. Lame aps encodes will still be very good. All mp3gain does is lower the volume (quantitative), which reduces the chance of clipping (which you're unlikely to notice anyway). Definitely worth it for the standardized album volume.