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Chopin A-flat major (Heroic) Polonaise Op. 53 and the Doppler effect (Read 1204 times)

Offline georgey

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Perhaps too exciting of a topic: ;D Iíve always thought that the magnificent E major section of this magnificent polonaise with the famous tough LH octaves playing over and over the notes do-ti-la-sol-do-ti-la-sol (as 16th notes) sounds like a train approaching.  It gets louder and louder until the moment it passes the listener and shifts to D#major due to the Doppler effect.

I guess 2 dumb questions:
1)   Anyone else felt the same?
2)   What would the speed of the train need to be in order to have the frequency fall a minor second as the train passes?

Reference recording start at 2:56 minute marker:



Off topic a little:  I grew up listening to Alexander Brailowsky playing the polonaises.  Maybe it was recorded in the late 1950ís.  I always loved his performance and it remains my favorite, even though it is a little sloppy.  

Offline andrewuk

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1) That had never occurred to me - nice idea, though it's perhaps unlikely that Chopin would have had enough experience of trains to be aware of the Doppler effect from them.

2)  Calculations of the Doppler effect give the relative change in frequency, so for a change of a semitone (or any inyterval) it doesn't matter what note you start with. In equal temperament a semitone corresponds to a frequency of the 12th root of 2 (because there are 12 in an octave, which is a 1:2 ratio), about 1.0595. Using the formulas from the website above, and bearing in mind that you have to consider the train both approaching and receding (so the "true" note, which you would hear if the train was stationary, is somewhere in between), I think that to give a change of a semitone the train would have to be travelling at about 10 metres per second (36 km/hour, 22.4 miles/hour). The calculation depends on the speed of sound, which can vary according to air pressure, and also wind speed, but I don't think these would change the answer much in the normal range of conditions.

Offline georgey

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1) That had never occurred to me - nice idea, though it's perhaps unlikely that Chopin would have had enough experience of trains to be aware of the Doppler effect from them.

2)  Calculations of the Doppler effect give the relative change in frequency, so for a change of a semitone (or any inyterval) it doesn't matter what note you start with. In equal temperament a semitone corresponds to a frequency of the 12th root of 2 (because there are 12 in an octave, which is a 1:2 ratio), about 1.0595. Using the formulas from the website above, and bearing in mind that you have to consider the train both approaching and receding (so the "true" note, which you would hear if the train was stationary, is somewhere in between), I think that to give a change of a semitone the train would have to be travelling at about 10 metres per second (36 km/hour, 22.4 miles/hour). The calculation depends on the speed of sound, which can vary according to air pressure, and also wind speed, but I don't think these would change the answer much in the normal range of conditions.


Thanks for the response!  Would be nice to get a second person to check this.  I clicked on your link and the web page is not available to me (plus Iím a little lazy).

Everything you say sounds correct to me and I will assume you are correct.  This takes away my theory of a train roaring by since 22 MPH is hardly roaring.  But I read just now that passenger trains of the 1830ís went about 30 MPH.  I spent about 5 seconds to see if Chopin ever rode on a train.  Nothing came up.  Trains in 1848 could go 60 MPH.  Chopin wrote Op. 53 in 1842.

Here is the sound of a train passing by my guess at about 30 MPH.  There is not a train whistle blowing (for example) as it passes.  So, it is maybe impossible to determine the amount the pitch changed due to the Doppler effect. But the Doppler effect is still clear in the train recording below.  

This train is not as fast or exciting as Kissinís 16th notes in my sample recoding link above of the Op. 53.   ;)  I donít normally like much of Kissinís playing, but he nailed this one!

Train passing by (start at 12 second marker):




Offline andrewuk

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For what it's worth, there's an answer on Stack Exchange that agrees with my calculation: "For a difference in frequency corresponding to a semitone ... the speed is about 36km/h"

Offline georgey

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For what it's worth, there's an answer on Stack Exchange that agrees with my calculation: "For a difference in frequency corresponding to a semitone ... the speed is about 36km/h"

Thank you!  I am convinced.  I thought maybe Chopin might of heard a train passing by at the train station if he ever rode on one.

The exchange says:
I have a background in music. People with a musical ear can generally tell the ratio between two frequencies (as a musical interval). For anyone who's not already aware, we perceive a ratio of 2:1 as an octave, 3:2 as a perfect fifth, 4:3 as a perfect fourth, 5:4 as a major third and 6:5 as a minor third.

Not quite accurate.  Sounds like he is describing something similar to Pythagorean tuning (at least down to the perfect 4th), not equal temperament like you did: minor 2nd =2^(1/12) = approx 1.0595.  Either tuning method though is close enough.



Offline mjames

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Horses mate.

Offline georgey

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Horses mate.

Please let us know your thoughts on this exciting topic, Mjamers. Don't be shy!   ;D

Offline georgey

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I spent the past 30 minutes doing google searches to see if anyone else had the opinion that the E major section of Chopin op. 53 sounded like a train approaching or anything to do with the Doppler effect.  NOTHING came up except my post.  I may be the only one in history that thought of this.  

I never assign programmatic elements to music, even if it is program music, except in very rare cases:  The lightning storm in Beethovenís 6th (pastoral) symphony that later clears when the sun comes out is one example.  Another for me is the vision of fairies and/or snowflakes dancing when I hear the ďDance of the sugarplum fairyĒ by Tch.  

My apologies if this topic offended anyone.