The next-best thing to hearing/seeing a symphony orchestra perform … is to see/hear one rehearse.

An experience I didn’t know was a “thing” until an in-law offered us two tickets to a practice session today by the Los Angeles Philharmonic, at Disney Hall in downtown Los Angeles. And we said, “Sure!”

Oh, and a key reason why I didn’t know rehearsals were open to the public? I am not a member of the orchestra support group known as “Friends of the LA Phil” — who are the people who get tickets to rehearsals and can pass them on, if they like.

Thus, we were among the 200 or so people lined up in the lobby of the Disney Hall at 9:40 a.m. to get an up-close seat in the “lower terrace west”.

And how did it go?

It was glorious.

Who knew rehearsals could be so grand?

In part, it must depend on the material that is being rehearsed, and who is leading the rehearsal.

We were lucky in two respects today, because the material given a close going over was Tchaikovsky’s Sixth Symphony, often known as Pathetique and described “by one scholar” (program notes) as “the most truly original symphony to have been composed in the 70 years since Beethoven’s Ninth.”

And the director was Michael Tilson Thomas, a native Angeleno, who brought a low-key vibe to the proceedings … speaking always in measured tones to the 60-odd musicians and injecting more than a few light moments disguised as instructions.

We were just a few rows above the bass section, and the sound, up that close, there is amazing. So good that you never want to go back to your music-playing devices again, not if you can have “live”.

Anyone with any sort of ear could pick out many of the individual performers, and watch/listen to them adjust as instructed by the maestro.

He spent most of his time on the fourth (closing) movement, the Adagio lamentoso.

Tilson Thomas spent most of an hour sharpening entries, shaping passages, picking out this or the other musician or group of musicians and explaining how he wanted things done, and why.

At one point he gently suggested that the strings were being “too lefty” — over-eager to rush notes into the piece — and he was particularly interested in how the French horns rejoined the music, and with how much volume.

He several times asked for this or that group to be a bit more assertive, but ultimately drew a line under that by noting, “We wouldn’t want 47 consecutive bars of triple forte, would we?”

The rehearsal was focused on key moments in the piece — those that are memorable, not necessarily those that are difficult. Which I suppose is how professionals work. We already know everyone has mastered their instrument; now it is about interpreting it.

We were perhaps 25 yards from the bass players, and another 10 yards from the director, and to hear the whole of the orchestra working and reworking the piece — and especially the key bits, so close — was like being invited to a semi-exclusive party.

We sat through the other piece of music being played at the Disney this weekend, the “modern” (yes, “uh-oh”) and often dissonant “Four Preludes on Playthings of the World” — written by Tilson Thomas himself. Not as interesting, at least to this non-professional.

We got to Disney Hall using Metrolink. We picked it up in Orange County and rode it straight to Union Station, where a shuttle took us to the music.

After a stop for lunch at Grand Central market, we walked back to Union Station and got the 3:19 p.m. departure out of L.A.  The train was surprisingly (to me) crowded.

A good day. Great music, up close, a new experience on the train … all good.