This is 7/8. Your counting pattern doesn't line up. If it did, the first group of the "12 12" would hit the accents set up by the groups of 3. In other words, it would be _4_ evenly spaced notes at the beginning of the phrase:

X__X__X__X_X_

Notice how the four first notes each have 2 rests between them? That's not what is in the audio. The groups of two are delayed. The actual counting pattern is: 123 123 1234 12 12

X__X__X___X_X_

Putting the second unaccented note in gets:

XX_XX_XX__X_X_

The correct rhythm is:

| 1e_a 2_+a __+_ 4_ | 1e_a 2_+a __+_ 4_ |

7/8

If you're playing it hand to hand, try this: RRL RRL RRLL RLRL

Try it to a metronome, it's about 212BPM

13 subdivisions still isn't quite perfect, but it's closer than 14 (i.e. 7/8). It's somewhere in between, which makes sense considering the composer just manually looped a sample that wasn't an exact measure of any standard time signature.

Can someone explain what a "standard time signature" is, in terms of frequency, for someone who has no clue whatsoever about music theory? As far as I understand it, there's a duration which loops (e.g. 0.5 sec for 120 bpm) and then you subdivide that into something (I guess).

How can this not be an exact measure of a time signature, since you can pick an arbitrary amount of time, loop it and subdivide it into parts?

There are a number of different subdivisions. First there is the bars, that you could define as a complete cycle. Inside the bars there are beats, often 2 or 3 per bar, most often 4. Then each beat is divided in 2 or 3 parts.

Then you can play it slower or faster, that's the tempo.

Notice that it's just about the rythm of a song. The actual notes you can place on it wherever you feel. Of course you want them to match some subdivision for them to feel "right" but often intentionally shifted for expressivity (swing).

Some standard signatures are:

4/4 - Bars of 4 beats naturally divided in two (most songs)

3/4 - Bars of 3 beats naturally divided in two (waltz)

2/4 - Bars of 2 beats naturally divided in two (march)

12/8 - Bars of 4 beats naturally divided in three (used in blues)

The /4 or /8 difference is moot. It's the duration of the beat, but you can compensate it with tempo.

That helps, thank you! Given that bars contain beats, why is the Terminator theme such a mystery? Doesn't it also have bars that contain beats? Or is the problem that the beats are so irregular that they aren't spaced somewhat evenly in the bar?

The term "standard time signature" isn't a technical term. I just meant it to refer to time signatures with relatively low integers, as opposed to something crazy like 101/32.

Rather than 13/8 I would say it was alternating 9/8 (three triplet beats, 123123123) and 4/8 (2/4? same thing right? 1212) measures. I guess that's just a matter of notation, but I'm used to seeing it like that in heavy metal that will throw in a 2/4 once in a while where needed.

Yes, it could be printed that way. Every classical musician I know hates it when editors do that, though -- it's exactly the same amount of work to keep track of the beats, but the alternating time signatures eat CPU cycles because you have to make sure that every change is the one you expect.

Ah yes, you're right. Thank you, great way of explaining it.

"1 (2) . 4 (5) . 7 (8) . 10 . 12 ." isn't a time signature.

It's 7/8.

Of course that isn't a time signature. It's a listing of where the loud notes, quiet notes, and rests line up in the bar.

It's definitely not straight 7/8.