The fact that Saturday night’s concert of the Mainly Mozart Festival Orchestra was excellent is certainly not news – and absolutely no surprise. The ensemble’s leader, David Atherton, is a remarkably fine conductor and we have been privileged to enjoy him here in San Diego on a regular basis ever since that sorry day he left the leadership the San Diego Symphony.

The big news is the venue – the 534-seat “lecture hall” at the Qualcomm complex in Sorrento Valley. One enters this place – a 10-story office building designed by Delawie Wilkes Rodrigues Barker -- through an undistinguished albeit spacious atrium redolent of “break time.” It’s a sterile space sprinkled here and there with some comfy lounges and cafeteria-style tables with chairs. Several floors of glassed-in office corridors overlook this open vista.

One enters the “lecture hall” from doors on two different levels – and, my goodness – it certainly looks like a concert auditorium! And an ideal one at that! Wooden acoustic clouds hang from above. The stage is all warmly teak (or so I conjecture). The architecture is hardly what I would call breakthrough progressive – like Frank Gehry’s Disney Hall, for instance. The layout of the place is handsome although not really stunning, and it dully repeats some of the corralled, multi-leveled modular awkwardness one often sees in the audience seating spaces. And yet, before you have even heard a note played, you know this place is perfect for chamber ensembles.

Once the music actually began, I was struck by the bright clarity of the acoustic environment. From my vantage point (an “upper” main floor not far from the back), I could distinguish sound of each instrument. And while this transparency was remarkable it did nothing to spoil the sum of the ensemble. Sonic blend is often partly the result of a highly reverberant hall. The colors become blurred, so to speak, smoothing over the rough spots. In this new Qualcomm Hall, woe to any amateur band with sections producing dubious intonation. The culprits will be spotted in an instant.

Atherton, of course, handpicks his players, and he clearly makes the most of his rehearsal time, because his Mainly Mozart Festival Orchestra is pretty much top notch. You’d think they do nothing but play together all the time. The program:

• Johann Christian Bach: Symphony in D, Op. 18, No. 4
• Mozart: Concerto for Violin & Piano in D, K. 315f (“reconstructed” by Philip Wilby)
• Johann Sebastian Bach: Concerto for Two Violins in D minor, BWV 1043
• Mozart: Symphony No. 36 in C Linz, K. 425

The featured soloists were violinists Martin Chalifour and Ida Levin, and pianist Anne-Marie McDermott.

By far the most unusual piece on the program, the Mozart double concerto, was also one of the most enjoyable. The fact that nobody is likely to hear it again—ever—was confirmed from the stage by Atherton himself. What Philip Wilby did was take some surviving measures from a piece Mozart never finished and fill in the considerable blanks to make a complete first movement. Then he turned to the Violin Sonata in D major, K. 206, orchestrated the final two movements of that, and then tacked them on to the concerto. Be assured, there is a rationale for all this, and Levin and McDermott played the work as if it were one of the gems on the entire established repertoire. Somebody should record it this before they leave town.

We do not hear too much these days from Johann Christian Bach, one of Mozart’s worthy contemporaries, so the Symphony in D was a treat, especially in such a finely etched, spirited reading. The Johann Sebastian Bach two-violin concerto, of course, was predictably ravishing with Chalifour and Levin teaming as soloists. Who can resist that lyrical second movement that flows gently forward in a seamless echoing dialogue between the featured instruments?

With superbly judged dynamics and nearly flawless ensemble, the great “Linz” symphony finished a marvelous program in what has to be a top new concert venue for our town. One hopes the lectures won’t drive out the music.