Let There Be Rock

215 independent analyses of this recording were submitted to AcousticBrainz. A bare majority of them — 51% — put it in A major, a key signature of 3 sharps. The tempo printed above is the median of the 215 readings; 99% of them land within 2% of it, and they barely differ at all.

At 90.6 BPM one beat lasts 662.3 milliseconds, so a sixteenth note is 165.6 ms and a dotted eighth 496.7 ms — the delay times for this recording. Counted half as fast it is 45.3 BPM, counted twice as fast 181.2. A score would mark that Andante, by the ranges this site uses.

The analyses put the reference pitch of the recording at 432.2 Hz, which is 31 cents below concert A at 440 Hz — the sort of drift a tape machine or a slightly different mastering leaves behind. That is a fact about this transfer of the music, not about how it was played.

The dynamic complexity of the recording measures 2.91 dB: that is how far the level wanders from its own average, so a small number means a loud, flat master and a large one means a recording that still breathes. Its average loudness is 0.933 on Essentia's 0-to-1 scale, which is not decibels and is not comparable to a streaming service's number.

10 other recordings here are in A major; the ones listed below are the closest in tempo.