I compared the dynamic range of the original 3 CD set to the new, hi res files and the dynamic range is actually quite a bit higher for the originals. There is a pretty good amount of compression on the new digital files and CDs. I have no idea why that was necessary.
I am going to clean the LPs tomorrow and starting listening.
My 8-CD set arrived yesterday, and I can report some impressions compared to the 3-CD set that I also have.
Hard to say if it is more compression or just a different mix. First, it is important to compare apples with apples, i.e., exactly the same tracks. It's easy to make mistakes here with so many takes. Initially, I compared
The Beehive from the 3-CD set with the first
The Beehive on the new 8-CD set, and they are not the same takes. So that was a mistake, apples to oranges. The take corresponding to the 3-CD set is on CD 8 of the new set, I believe. And the different takes are mixed quite differently, both within the 8-CD set and compared to the 3-CD set. So that's already a problem right there for comparisons.The mid-bass also seems more prominent overall in the new CD set.
Given that, I decided to compare the sole
The Sidewinder tracks on both CD sets, applies to apples (an added complication for comparison is that both CD sets have different overall loudness, so you have to diligently adjust). Yet also here the mixes are very different. In the new 8-CD set the drums are mixed much more to the foreground, which diminishes the dynamic range right there, without even considering actual compression -- on the 3-CD set the drum intro is much softer, but the drums are mixed in less prominent throughout. The brass tutti then seems relatively louder and more incisive on the 3-CD set, because it is more in the foreground due to of the lesser prominence of drums.
Comparing the relative volumes in the first trumpet solo in that piece between the two CD-sets should give a clearer picture with regard to real compression. Compared to the intro brass tutti, Lee Morgan's first solo lick (at 1:42) is quite a bit softer in both CD sets, and the next phrase is considerably louder in both sets too. Hard to say how much relatively in each case, because the different prominence of drums muddles the picture a bit (the locations of instruments also differ between the CD sets). Morgan then fades out his trumpet playing with ever more quiet notes towards the end of his solo (around 4 min), and that volume effect seems to be comparable in both sets. So I am not sure if there is any compression in that, when it comes to the new 8-CD set. Obviously, an overall dynamic-range spectrum will not tell you about those things since the drum prominence is different, you have to listen for parts.
Regardless, I am glad that I have the 8-CD set now as well, I look forward to an interesting musical comparison of all the different improvisational takes on the same compositions (several of them, like
The Beehive, Absolutions, Something Like This, were played all three nights, Friday to Sunday, July 10-12, 1970).