When my sister and I were very small, our parents bought a copy of the London Symphony Orchestra’s seminal recording of Holst’s The Planets, recorded under the masterful baton of Sir Colin Davis. We immediately established it as our preferred improvisational dance music: so much so that we regarded it as ours, not as theirs.

When it came with us to Mom’s new house after the divorce, the capacious living room allowed us the freedom to improvise wildly theatrical “performances,” most of which took place when Mom was out. We would dance our way through the whole thing, incorporating every shred of ballet training we had (and making up the rest from whole cloth).

There was something in that music that really spoke to us. It was magic: old, wild magic.

Imagine, then, my shock and dismay when I hit up Prime Music for the recording and found the old, wild magic gone!

I found myself questioning my musical memory (which is very, very accurate). Had my child’s brain imagined the expression, the passion? Had the playing always been this, well, bland? Where were the dynamics, the shifts in tempo that lent such expressive elan to the LSO’s work?

And then “Jupiter, Bringer of Jollity” came on, and I got it: This wasn’t the same recording. Couldn’t be.

And, in fact, I was right: in my late-evening fumblings, I’d tapped the wrong album — the recording I had been listening to was produced as a movie soundtrack (it appeared right next to the London rendition on my tablet’s screen; evidently, my aim was untrue).

Of course!

It all made sense. Movie soundtracks, by necessity, can’t always be as expressive as the London rendition. They’d upstage the action on screen if they were. Their purpose is to help to move the story along without getting in the way of the words spoken by the actors (and to surge, when called upon, in sorrow or triumph — or in order to facilitate a montage).

I stopped the recording, fired up the London version: yes, there it was, in all its glory, exactly as I remembered it. Dynamics, tempi, and all.

There’s a lot of dance implicit in that music — and that’s missing from the blander soundtrack rendition.

The London recording is music for dancers (well, really, for musicians, but it comes out the same in the final analysis): it can afford to be expressive. Dancers feed on that.

It can afford to pay with tempi, with fermatae, with caesurae (if you’re not a musician, those are all modes of expression related to timing); it can afford to swell through mighty crescendi and ebb through delicate diminuendi. Like orchestral music, dance is more interesting when the timing is dynamic; dancers, meanwhile, enjoy a symbiotic relationship with changes in volume dynamics.

Dance performance depends on counting, of course, and technique — but, in the end, the dancer’s ability to feel and interpret music is what makes or breaks a performance. We can forgive the cavalier for not quite making that lift if we believe him; Odile can miss a few fouettées if she makes us believe.

That belief is founded in expression.

Holst isn’t everyone’s cup of tea (who is?) — but he wrote dignified, playful, magnificent music; the kind that, in the hands of a good orchestra, lays a great foundation for ballet. It’s voluble; it’s expressive.

In the end, that and a good beat are what most of us look for in music for any kind of dancing. Maybe not so much in music for movies — but for a ballet, an East Coast swing, or even just a good old-fashioned booty shake, that’s it.

To borrow a phrase from a movie: Kinda makes ya feel like riverdancin’.