DISNEY'S VITAL ORGAN.

Byline: David Mermelstein Correspondent

It's known as the King of Instruments - and often sounds like the Voice of God. Composers from Bach to the present day have employed it to convey celestial messages in their fashion.

Even the musically challenged have no trouble distinguishing this instrument's sound. Yet the manner in which it produces uncanny music remains mysterious to most.

Designing one requires the vision of an architect, the rigor of an engineer and the meticulousness of a master craftsman. We are, of course, speaking of the pipe organ, and newborns of this species arrive only rarely.

Which is why so much attention is being lavished on the Walt Disney Concert Hall's new organ, which makes its debut tonight. Now, a year after the hall opened and following months of precision adjustment, the organ - which up to now has been a silent centerpiece - is about to sing publicly for the first time. The addition of this massive instrument - weighing approximately 44 tons and costing the Los Angeles Philharmonic roughly $3 million - is certain to have far-reaching effects on the Philharmonic. At minimum, it provides the orchestra with a means of playing scores previously beyond its scope.

``The organ adds a dimension. It's something you can't replicate any other way,'' says Fred Bronstein, president and CEO of the Dallas Symphony Orchestra, which in 1992 installed a pipe organ at Meyerson Symphony Center, its highly regarded I.M. Pei-designed concert hall.

``There are works in the symphonic repertoire that cannot be truly heard without a great organ,'' says Edward Yim, the Philharmonic's director of artistic planning. He notes that, literally and metaphorically, the presence of Disney Hall's organ will be felt immediately. ``You want to feel the seats rumble and the building shake at those moments. Performing these works without a great organ is like trying to perform a Mozart piano concerto on an upright rather than a concert grand.''

The real challenge, though, may be quieting this instrument when the Philharmonic opens its 2004-05 season tonight with the first of three programs featuring the organ and several notable guest organists.

The new organ is unusual in many ways, but nothing sets it apart more than its facade, an unconventional collaboration between the hall's architect, Frank Gehry, and the instrument's creator, Manuel Rosales, a 56-year-old Angeleno devoted to organ building, maintenance and restoration.

The project is the biggest yet for Rosales and his longtime associate Kevin Gilchrist.

Rosales was initially skeptical of Gehry's vision, but a mutually respectful working relationship emerged. The compromises resulted in innovations like using wood, which produces deeper and sometimes louder sounds, instead of metal for the large curved pipes that are now a Disney Hall signature.

The bulk of the organ's machinery is concealed, though. Audiences will see only 124 of its 6,134 pipes. The rest - some thin as pencils, others thick as telephone poles - lie within a divided structure nearly four stories tall, a veritable forest of vertically mounted wooden and metal pipes.

The organ was completely installed when Disney Hall opened last October, but since then Rosales and Gilchrist have worked 30 to 50 hours a week balancing the sound of the instrument against the auditorium's acoustics. The process involved voicing (adjusting the tone and volume of the pipes) as well as tuning and proved all the more difficult because the hall is seldom empty.

``Originally, we thought we'd work from midnight to 8 a.m.,'' Rosales says, ``but my brain didn't function well then.''

Instead, he and Gilchrist worked piecemeal, arriving before orchestral rehearsals, then taking a break for other work, returning before concerts, leaving again and finally coming back after 10 p.m. for a few more hours.

Despite their size, organs are wind instruments. Sound is produced by forcing pressurized air (from three motorized blowers, in this case) through pipes, resulting in tones that resemble, but don't mimic, various instruments, including flutes, bassoons, trumpets and even strings.

The sounds are generated at a console consisting of keyboards, pedals and stop controls. (Stops allow the organist to chose which pipes may be played.) Disney Hall's organ has two consoles: a largely mechanical one installed permanently at the base of the visible pipes and a mobile electronic one that can be positioned at four locations on stage.

The instrument has 109 ranks, which is what sets of organ pipes are called. A block away, the organ at the Cathedral of Our Lady of the Angeles, built by the Dobson Co. of Iowa, has 105. Extra pipes allow for greater variety, not greater power.

``No two organs in the world sound alike, even if they look alike,'' said Rosales. ``And no two organists have the same preferences. So when you enter the organ world, you enter a world of uncertainty and unpredictability.''

Ultimately, an organ reflects the prejudices and preferences of its creators. Disney Hall's new instrument is capable of producing the sound of wind chimes but not church chimes, bird songs (from pipes immersed in water) but not drums. Rosales has said that he wanted to create sounds the Philharmonic itself could not produce.

Though reluctant to pick favorites, Rosales has special feelings for two of the organ's more brazen ranks. The one named Trompeta de Los Angeles is hard to miss: made of brass, it bursts horizontally above the stationary organ console. The other, called Llamada, rests unseen atop the organ and has a smooth, trombone-like sound. Its name means ``to call'' or ``to welcome'' in Spanish.

Rosales says he imagines the two ranks being played simultaneously, producing a brilliant brass fanfare. ``If you get the metaphor,'' he said, ``it means 'Welcome to Los Angeles.' ''

LOS ANGELES PHILHARMONIC ORGAN PROGRAMS

Where: 111 S. Grand Ave., L.A.

Tickets: Call [phone] or go to LAPhil.com. Prices vary.

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2 photos

Photo:

(1 -- cover -- color) We're pulling out all the stops for our fall ARTS PREVIEW

Manuel Rosales warms up on the 44-ton Walt Disney Concert Hall organ, which he built and maintains.

(2) no caption (organ)

David Sprague/Staff Photographer