I've noticed that sometimes a different recording of the same piece will sound like it's being played in a different key. For example, I listened to Concerto No. 6 in B-Flat Major, BWV 1051: III. Allegro in a recording by Richard Egarr and then one recorded English Baroque Soloists. When I compared the two, the Egarr version sounded to me like it was performed a semi-tone higher than the EBS recording. If the piece is in B-Flat Major, shouldn't both performances sound like they are in the same key?


2 Answers 2


The difference, in short, is because one of the ensembles is using historical tuning practices.

The modern pitch standard is A440, meaning that A4 (the A above middle C) is 440 Hertz. Not everyone uses this; last I heard, the San Francisco Symphony uses an A a little higher (442, perhaps), and some push it down to, say 438. But A440 is nevertheless the international point of reference.

But the fact is that this wasn't always the case. Performers interested in historically accurate performance, especially with the use of period instruments, have settled on this A4 being a half step lower at 415 Hz.

As a slight digression, this is one upside of used fixed-do solfège without chromatic alterations in the syllables. If you're playing a piece in D major on modern instruments, that matches our "re" solfège syllable. And if you're playing it in historical tuning (a modern D♭), that's still "re"!

And speaking of D major, here are two samples for anyone unsure of what this difference sounds like: here is Bach's fifth Brandenburg concerto (in D) played with modern tuning; here it is with Baroque tuning.

  • Lovely answer.I'm still not convinced that having a different reference point for A (for example) will affect most people. Those with absolute pitch may love/hate the change, but us mere mortals - I really don't think it's much more than snake oil. It's akin to changing key in a piece (question imminent) so does that make the original or the new key better..?
    – Tim
    Jun 25, 2019 at 16:47
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    I fail to understand the solfège argument. Surely using fixed do with or without chromatic alterations, d is re regardless of whether the frequency of that note is 587 Hz or 553 Hz. I also note that some period groups will use 430 (for late 18th century music) or 466 (German Chorton and early 17th century Italy).
    – phoog
    Jun 25, 2019 at 16:49
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    @Tim Using 415 instead of 440 has a lot to do with the scale of the instruments and therefore their tone. When you transpose a piece, you play different notes. When you tune the instrument to a different pitch, you change its basic sound.
    – phoog
    Jun 25, 2019 at 16:55
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    In my previous comment, by "scale" I meant "size," not musical scale. If you tune a harpsichord up a half step, for example (assuming it's not one of those with a keyboard that slides left and right), or any string instrument, you don't shorten the strings but make them tighter, which affects the tone of the instrument.
    – phoog
    Jun 25, 2019 at 19:37
  • @Tim: Instruments have fixed ranges and sound different in various parts of those ranges, so if you were to change the tuning of 'A' by, say, a fifth, it would definitely make a very perceptible change in the way the piece sounded. The smaller the pitch change, the less perceptible the difference, but in principle it's always there. That said, the difference in instruments and technique probably overwhelms this difference long before we get to these changes of a few Hz around the middle of the keyboard. Jun 26, 2019 at 16:31

Leaving aside the possible of different recording speeds, the half-step change in the pitch of the reference note will be noticeable to a lot of people. Modern example: Jimi Hendrix often (well, often enough) tuned his guitar down a half or whole step.

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