It's very rare that I'd slam a CD for poor sound but in the case of this recent Abbado Mahler 7 potential buyers need to be aware of this issue.
There is a lot of microphone switching going on through the performance. It may not be immediately noticeable when listening in a room, though it does give a sense of unnatural balance and overall sound picture. However, when listening on headphones it is very clear that the balance changes from bar-to-bar, which is very disorienting.
It's extraordinary that companies with the pedigree of DG cannot produce well balanced natural-sounding recordings as consistently as they did 40 or 50 years ago. Their old Abbado recording from 1984 certainly sounds more natural than this, and even Kubelik's live radio relay on Audite is preferable.
The less than perfect sound is a great shame because the performance itself is stupendous with the Berlin Philharmonic on electrifying form throughout. A missed opportunity then.
For reference, here is Gramophone's 2002 review, which also mentions the same issue with the sound:
"Abbado's authority in No 7 is unquestionable. His 1984 studio recording remains one of the top three - less minutely responsive than the first, 1965 Bernstein (partly a matter of CBS's close-up sound), mellower and more poetic than the 1993 Gielen. DG's sound in Chicago was good, but I was hoping for more brilliance, less plush and a cleaner focus from Berlin, making this new contender a clear first choice. As ever, life is not so simple. Abbado's view of the first movement is little altered. With some tremendous horn playing and fabulously articulate strings, the music feels somewhat darker than before. The middle movements have lost none of their improbable delicacy and flair. In Nachtmusik I, the ear-stretching echo effect of the opening bars is again boosted by the determinedly antiphonal placement of the horns, and the mood remains fantastical, less strident than with Bernstein. The changes elsewhere seem marginal -such matters of detail as the restoration of some tremolos in the mandolin in Nachtmusik II, or more being made of the string glissandi in the central scherzo. Only the driving impulse of the finale, subjectively more insistent than previously, detracts just a little from the characterisation of individual episodes; the orchestra, for all its corporate strength, isn't quite beyond reproach by the close. It is on sonic grounds that the marginally more ebullient, less refined Chicago version would get my vote. DG, on the new release, gives us another concert relay in which you don't feel you've been given a decent seat in what is, admittedly, a difficult house. There's so much switching between microphones that it becomes difficult to get a proper 'fix' on players operating in a stable acoustic space. Those who listen on headphones are likely to be especially bothered by the intermittent loss of bass frequencies. There are momentary contractions of the sound stage as early as 017", 041" and 104' into the first movement, so - if you can - try before you buy. Not that I'd want to put you off acquiring what is notably deft and atmospheric account by possibly the greatest Mahler interpreter of his generation. If the conducting is inclined to underplay the drama of the moment, sufficient sense of urgency is sustained by the combination of well judged tempos, careful nuancing and precisely weighted, ceaselessly changing textures."