Originally submitted by George Badland on Wed, 23/09/2015
In the next song we will be learning, you will see a few places on the score where spelling the chords correctly has created instances where adjacent notes look different but are actually the same note on a keyboard. In consequence some of you may wish to know why that should be so.
Well, in western music, the vast majority of work is written and performed according to the tempered scale*. This is a system developed a few centuries ago where every note, interval or key signature, has what is known as an enharmonic equivalent. An Example would be F# and Gb, where on the piano they are one and the same note. Other examples would be Cb and B. Also Dbb and C. On the keyboard the notes are identical, pitch wise, but have different names. That is, they have been 'spelled' differently and are therefore enharmonic.
Similarly with keys. The key of Gb is the enharmonic equivalent of the key of F#.
As far as we are concerned, all this only really applies to music in the tempered scale where all the note frequencies are modified, very slightly, from the natural scale, in order to make each octave consist of 12 equal semitones. This in turn, enables all instruments in an orchestra to play together in different keys. Something that was not possible hitherto, circa 1700 AD.
In barbershop, we try to tune our intervals according to natural frequencies, also known as 'just intonation'* where each interval will be very slightly different to the similar tempered interval you would get on a piano, or with any other fixed pitch instrument. This is why we sing acapella. I.e. Without instrumental accompaniment, so we can adjust our pitches without creating poor intonation.
If we take a note from the scale of C. Let us say it is the note E. Well, the major chord of C will include the notes C, E, G. We can see from that, that the E note is the third interval. (we have to count the first as 1 so D would be the second and E the third.)
If we now consider a similar chord in the key of A, we get A, C#, E. However, our E note has now moved from being a third to becoming a fifth, so in the just intonation scale, this E note will have a slightly different pitch to it than the previous E note which was in the third position. Such movement of interval, is happening all the time when we are singing. As we move from one chord to another, notes are continually changing position, in one bar they may be in root position, in the next fifth position or seventh and so on. Now because of this movement of position, along with the knowledge that each position requires the note to be tuned very slightly differently, it is important to know what each position our notes are in is so we can tune accordingly.
So, going back to our new song, those identical but differently spelled notes I mentioned, maybe the same note on the piano, but we will be tuning each one very slightly differently as their positions within each chord changes.
Fortunately, we don't really have to know all this, because barbershoppers can 'hear' what is happening and what they need to do in order to adjust their pitch to achieve those wonderfully ringing sounds.
Well, most can.;0)