There are at least two recordings on Youtube of Bach's Brandenburg Concerto No. 5 in D major which seem to be played a half-step lower, in the key of C sharp. I assume this is a artifact of the recording process or uploading to Youtube but wonder if there isn't some tradition of which I am ignorant in which older pieces are thought to have been played in a register other than that determined by current standards (with their very precise association of wavelength and musical notes)?

The first example at 18:43-44 gives the sustained D at the end of the piece. The second example gives the same sustained note at 19:36-38, but according to the various online tuners (here is one) the first example is D and the second is C-sharp.

Here is another example in which the piece seems to be played in C sharp major instead of D. The final sustained note at 21:23-24 can again be checked with any online tuner or compared to the first example above.

Obviously this doesn't affect the quality of the recordings or performances, but that it occurs more than once makes me wonder what's behind it.

Any insights appreciated.

  • 5
    Personally, I think this is a very good question and I'm a bit confused about how two people thought this question was good enough to answer but not good enough to upvote. Perhaps to them the answer is obvious, but to me even that wouldn't detract from its quality. Welcome to Music.SE! Dec 25, 2016 at 12:38
  • @ToddWilcox: Appreciate the welcome! You raise a good point which someone apparently noticed.
    – daniel
    Dec 25, 2016 at 16:40
  • YUS. Great question. I've noticed this with Vivaldi's Concerto Grosso in B Minor, and, as I noted on chat a week or so ago, modern songs like Asleep in the Light. SO WEIRD. Dec 26, 2016 at 18:16
  • @ToddWilcox This is exactly the sort of observation which prompted my recent question on meta :)
    – Old John
    Dec 26, 2016 at 23:14

8 Answers 8


Tuning forks, invented in 1711, standardised tuning. (A student of mine used to call them pitchforks...) Trouble was, there was no standardised pitch for the note,that came much later. So various forks ranged from 400 - 450Hz, depending where they were made/used. I guess musicians didn't travel too far for engagements, so discrepancies in 'concert pitch' didn't matter too much, as long as everyone in one orchestra was tuned similarly.

Recordings had hardly taken off by then, but much later, when an orchestra did a recording, probably for the sake of authenticity, it would tune to what was considered the tuning of the original piece. Very difficult to ascertain, sometimes, so personal choice by the conductor was made.

There was also the mechanical transcription of an already recorded piece, from tape to whatever other medium, which meant that the tape may have stretched slightly, or the speed at the time of recording was not exactly the same as that on playback. This shows in so many pop songs from '50s and '60s. Sometimes accidental, others on purpose, trying to enhance the feel of a number.

  • 4
    To expand from experience: I've been concertmaster for several recordings, and the pitch chosen for a recording can vary from 400 to 440, depending on various different assumptions or preferences by/of the conductor. (This can range from following a previous recording's pitch to conveying "brightness" or "warmth" to compensating for real temperature fluctuations expected to affect instrument pitch)
    – Xodarap777
    Dec 26, 2016 at 23:14
  • @Tim What is the name of the student who called tuning forks 'pitchforks'? Why did he use the word 'pitchfork'?
    – Vighnesh
    Dec 21, 2023 at 14:48
  • @Vighnesh - long time ago, can't remember, but a doctor's daughter, well educated, and spoke perfect English. Family was from Sudan, but that's not pertinent. I thought it was obvious - looked like a fork and produced a certain pitch. Logical, really...
    – Tim
    Dec 21, 2023 at 15:03

As the other answers said, the standard for pitch was different in different locations and at different historical times, and even in a single place and time different standards were used for different types of music (e.g. secular and religious music).

Most wind and brass instruments have a narrow range of pitch adjustment, because the pitch is defined by the physical size of the instrument. Since manufacturing reproduction instruments for performing "early music" is now an international "industry", there is a general agreement on A = 415 Hz as a standard pitch, at least for the baroque period. That is close to a semitone below the standard pitch of A = 440, in which G sharp is 415.3Hz in equal-tempered tuning.

This choice of a semitone difference between the two "standards" means that instruments which can't easily be retuned (e.g. pipe organs) can be used at either pitch - either by the performer transposing the music by a semitone, or by a mechanical transposing device.

The difference of only a semitone might seem fairly immaterial, but it is significant in vocal music, particularly in soprano parts where the top note is often a written A. Lowering the pitch of such parts by a semitone can make a big difference in choirs made up of non-professional singers, where the "comfort zone" for the sopranos is more likely to stop at top G, not top A.

  • At that time, I think pipe organs were sometimes retuned. But what a task that must have been.
    – Tim
    Jan 1, 2017 at 13:00

Compare the YouTube video to authentic phonorecords of the same recording, such as pressed CDs or on MP3 files purchased from Amazon. If the transposition appears on YouTube but not on the CD, you're looking at Content ID evasion.

Though BWV 1050 and all other published musical works of J. S. Bach are old enough that no copyright subsists, the author of a sound recording of a musical work gets a fresh copyright for that particular recording. The major record labels routinely upload recordings that they control as reference material to automated fingerprinting tools for detection of copyright infringement, such as YouTube Content ID. To try to evade detection, some uploaders change the pitch of their unauthorized uploads, either slowing down or speeding up the whole playback or using a pitch-shift filter in an audio program.


There have been several standards for concert pitch over the years. I would guess that the performers chose one that they thought appropriate for the piece.




Other responses have suggested this, but none seems to have made it explicitly clear.

Based on the best historical evidence we have - historical organs, historical woodwind instruments, historical writings about performance and instrument making, and so on - musicologists generally believe that an A was around 415 Hz in the mid 18th century (though it varied by location much more than it does now, since communication and travel was so much harder), as opposed to A=440 Hz now. (Actually, most modern orchestras tune even higher, even up to around 450.)

Certain musicians have taken the attitude that music from the 18th century should be played as musicians played it in the 18th century, including using historical instruments (or copies of historical instruments) and historical pitch levels. Others have not.

The difference between A=415 Hz and A=440 Hz is about a semitone.

  • Read my middle para. It's pretty clear.
    – Tim
    Dec 29, 2016 at 12:35

In addition to other good points made, in string instruments and pianos/keyboards, there were technical issues which made it easier to maintain the instruments at less tension than has become the norm nowadays. As technical aspects improved, people often thought the newly-possible "brighter" sound of slightly skewed-upward pitches sounded better, and there we are. For example, older, weaker piano frames could not endure as much stress as nowadays. Similarly, older gut strings on violins could not endure higher tensions as well.


There's an easy answer and a complicated answer. The easy answer is that recording or performances made on original or "period" instruments from the time of Bach are almost always made one half step lower, so that the frequency of "A" is 415.3 Hz, compared to the 440 Hz or higher for modern instruments. In general, this is thought to reflect the lower pitches in use in the time of Bach, and many of the old instruments sound better at this pitch. The complicated answer is that the "key" is really not the pitch, although these terms are often conflated. So if you look at the original autograph of the Brandenburg Concerts on IMSLP, you will see that the key is the same even of the pitch is different. This is further complicated by the fact that in the Baroque many pitches were used, so 415.3 is actually a sort of modern convention that allows the harpsichord to play perfectly at both pitches by sliding the keyboard over on key. This is really handy and that's why we use 415.3 instead of 422 or other more historical pitches. You can see a performance on original instruments here, the performers are reading the music in the correct key (two sharps), but the sounding, reference pitch is one half step lower: Brandenburg 5 Original Instruments and pitch

  • 1
    Sliding the keyboard over on key' - what's that mean in layman's terms?
    – Tim
    Dec 28, 2016 at 8:47
  • I think it is a typo for "one key". @Tim
    – fdb
    Nov 16, 2018 at 17:52

In addition to #51500, this does not necessarily have to be intentional evasion, but could also be an effect of 25/24 framerate conversion, so everything is 1/25th slower and pitched down. Pitch correction, while possible in principle, would probably not go well with classical music.

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