The world that Mahler creates in his majestic orchestral works is at once beyond our grasp and nestled deep within our very soul.

There is mystery and clarity. Unbridled joy and indescribable sorrow. And in his final song cycle (or, if you prefer, song-symphony) Das Lied von der Erde, Mahler seems to sum up his life on Earth - and ours, as well.

This weekend in Boettcher Hall, Douglas Boyd and the Colorado Symphony are teaming with a pair of superb vocal soloists to present this extraordinary "Song of the Earth." It is something to be experienced, not simply heard.

On Friday, the stage nearly overflowed with musicians, and yet those moments of utter poignancy emerged when all but a handful of players fell silent. In those passages, where a single voice was accompanied by a flute or rippling celeste or plaintive oboe, magic resulted.

Returning for his second week, Boyd (the orchestra's principal guest conductor) proved a master of Mahler, maintaining a transparency that is much-needed but difficult to obtain. His control of the orchestra was complete, and yet his players seemed to breathe on their own, giving a performance that had a subtle sense of spontaneity rarely encountered in the concert hall.

Terrific work from the winds collectively, and from Pam Endsley (flute), Peter Cooper (oboe) and Bil Jackson (clarinet) individually.

The two singers were mic'd, their wonderfully shaded voices sounding not so much amplified as tastefully boosted. Tenor Stuart Skelton was overwhelmed by the ecstatic French horn fanfare that launched the opening Drinking Song of the Earth's Sorrow, but he quickly gained strength (or got a boost from the sound man) and provided exemplary singing through his three solos. Mahler doesn't call for too many notes in the upper range, but he does demand power and focus - and Skelton delivered.

Mezzo Jane Irwin handled the remaining three songs, triumphing in the extended, ethereal Farewell, which ends the work and carries us off into an eternal world beyond this one. Irwin never tired, never faltered and caressed each word, each phrase with loving attention. This was unforgettable music- making.

Earlier, Boyd and the reduced CSO offered a reading of Haydn's early Le Matin symphony, which bubbled with charm and some terrific solo playing from Yumi Hwang-Williams (violin) and Jurgen de Lemos (cello).

Shulgoldm@RockyMountainNews.com or 303-954-5296

COLORADO SYMPHONY

* Grade: A-

* When and where: repeated at 7:30 p.m. today in Boettcher Hall, 14th and Curtis. There is no Sunday performance.

* Cost: $15 to $73

* Information: 303-623-7876