The presence of a live audience during a jazz or blues recording can certainly turn up the creative voltage, but it is open to question whether the presence of a recording crew during a concert necessarily improves the performance.
B.B. King has certainly wearied, over the years, of being told that his 1964 album Live at the Regal is the ultimate live recording of electric blues. For many people it undoubtedly is, but the artist himself has always maintained that he and his band sounded like that every night that year. Furthermore, he has made several truckloads of albums since, quite a few of them live recordings, and it irks him that none are held in the same esteem.
Pianist Keith Jarrett - he would prefer to be considered a multi-instrumentalist but almost all of his best music has been improvised on grand pianos - has the same problem with The Koln Concert, recorded and released in 1975.
The performance circumstances were not ideal. Jarrett, a prickly character at the best of times, was sleep-deprived and suffering acutely from back pain. The piano on which he was asked to perform was a severely substandard instrument.
But the show was recorded and issued. It went on to sell more than 3.5 million copies and, according to Jarrett's record label ECM, it remains 'one of the best-selling 'jazz' albums of all time, as well as the best-selling solo piano album in any genre'.
It gained a new lease of life when reissued on CD, and Jarrett, who is still living in its shadow, has said he would like to have it deleted from the ECM catalogue.
There isn't much chance of that happening. Jarrett and the label have an excellent relationship, which last year marked its 40th anniversary, and ECM boss Manfred Eicher believes in accommodating his artists, but he isn't stupid.
It's probably fair to say that ECM had been trying for a second lightning strike with most Jarrett releases since. Although it is an audiophile imprint that usually insists on rigorous standards of sound quality obtainable only in the studio, ever since Koln Jarrett has only to accept a concert booking to ensure that a truckload of recording equipment is parked outside the venue.
Since 1975 Jarrett has released around a dozen live solo piano albums, and many more live recordings in other formats, in addition to his prodigious studio output. Perhaps the most self-indulgent of the live exercises was 1976's Sun Bear Concerts, recorded in Japan, which ran to more than six and a half hours, originally issued in a set of 10 LPs. Jarrett is on the record as preferring several of his other live recordings to Koln, but his audience has failed to go along with him. He is particularly keen on the latest, Rio, recorded in April in Rio de Janeiro's Theatro Municipal, but this time the enthusiasm seems to be more widely shared.
Several people have described the album, which combines elements of classical and South American music with blues, gospel, free jazz and Jarrett's beguiling facility as a melodist, as his best since Koln, and on the basis of the first few listenings they may be right.
A strength is that it is not similar to that career landmark recording, although it shares its focus and coherence and, as usual, is entirely improvised from start to finish.
While The Koln Concert was originally spread over two LPs and consisted of three very long tracks and one relatively short one, at just more than 66 minutes it fits comfortably on a single CD.
Rio is a double-CD set that runs to more than 90 minutes, but is composed of 15 separate tracks, of which the longest is less than nine minutes and the shortest only about three. None has a title, beyond the simple Rio Parts 1 to 15.
Jarrett's fans will love it. Those new to him will probably find this an attractive introduction, provided you don't too much mind the grunting, humming and other vocal interjections which are part and parcel of his improvisations.
Three other noteworthy releases from Jarrett.
Standards Live (ECM, 1986): the solo marathons tend to overshadow Jarrett's ensemble playing, and after three years working together the rapport here between him, bassist Gary Peacock and drummer Jack de Johnette is extraordinary.
Vienna Concert (ECM, 1991): a strongly classically influenced solo improvisation. The locations of his concerts seem to influence their content. In his view a more satisfactory 'artefact' than Koln.
Rarum 1 (ECM, 2002): Jarrett's own selection of his work from the ECM vaults presents music he thinks got less attention than it deserved at the time, and includes performances on instruments other than the piano.