Hi Greta, I did check every track.
To your questions about frequencies:
The presence of higher frequencies (or any frequencies really) in the rip depends on various factors. One is the quality of the ripping setup, but another one is of course the presence of these frequencies in the original recording and the music itself.
We have to distinguish two independent aspects here:
(1) Whether a rip is genuine and not transcoded from a lossy source.
(2) Whether the rip is actually "good", meaning that it has a good sound.
The problem to solve here was (1), and the answer is conclusive: the rip cannot be the result of a transcoding from an MP3 file or even an Ogg Vorbis file because it contains high-frequency noise that these encoders discard, at least partially.
Regarding aspect (2), this can only be decided by listening to the rip on a capable stereo system. It would of course be optimal if we could also compare it to the sound of the original recording, but this will rarely be an option.
If very high frequencies (except noise) are not present in the spectral analysis of a track this may be caused by their not being present in the original recording. It does not have to mean -- although it can mean -- that the recording (or the rip) was bad. It can simply be the case that the music itself did not contain these frequencies in the first place. I would encourage you to take a classical piano recording (solo piano), Erik Satie for example, and look at the spectrals. You may be surprised.
And, yes, the loudness (dynamics) of the recorded sound also plays a role for the visual appearance of the spectral analysis, as the colours in Spek encode the loudness of frequencies.
