With
Equal Temperament tuning, although the octaves are exactly
in tune (Ratio 2:1), all the other notes are 'slightly out of tune' (and some more than others). When notes are 'out of tune' mathematically (ie. they are not in perfect ratios) not only does the ear perceive them as such, but you get 'beats' sounding when you play the two notes together. On the plus side, whatever discrepancies' there are,
they are the same whatever key you are playing in. Or another way of putting it, because we want our modern instruments like pianos/organs to work in all keys, we divide the dissonance up between all keys equally.
There are some who think the sound we get from Equal Temperament tuning lacks 'colour', and Yamaha deliberately tuned their AR Series organs (AR80 and AR100) at different pitches in certain areas to make them sound 'richer'. The only part of the organ that was tuned to Standard
A 440Hz pitch (zero) was the Lower Manual, and in their instructions they tell you that if you are wanting to 'tune' orchestral instruments from the organ you must choose the
Clarinet from
Lower 1 (with no vibrato) and play the
A 440Hz on the
Lower Manual. Below is a chart showing how Yamaha organised these changes of pitch.
The Pitch of the Yamaha AR .. (taken from the Owner's Manual)
When choosing VOICES for playing the melody, the upper manual has three areas where you can get your Voice from.
You can choose eg. a trumpet from the
LEAD VOICE section (VOICES chosen from this section are MONO so only play one note at a time .. if you play
two notes it will only play the higher one), which would then be pitched 6% higher than concert pitch. Or you could choose your trumpet from the
Upper Voice 1 section, which would be 2.4% higher than concert pitch; or from
Lower Voice 1 section which would be 1.2% higher. We are talking about the
same trumpet 'Voice' here!
Note: You can't actually choose a trumpet that's playing
at concert pitch!
When playing chords on the lower manual, if you wanted them to be 'in tune' with concert pitch you would have to choose eg. strings or choir from
Lower Voice 1. If you chose them from
Lower Voice 2 they would be 1.2% 'flat.
And your bass pedals are tuned to be 3.6% 'flat'.
Yamaha's idea of making the AR80 organ sound more 'colourful' certainly worked with me, as after listening to several organs including the Roland, I was so struck by the AR80 that I bought one (and still have it). When playing it, I would always choose my upper voice from the LEAD section, as that always sounded 'richer' to me when playing the melody.
I have a few examples of this for you to listen to, played by AR Group Members who play the organ a lot better than I do!
So click the below .. and tell me if
you think the solo instruments sound 'richer' because of what Yamaha have done.
Mark Burbridge playing Trumpet Voluntary on a Yamaha AR80 organ.
Don Wherly playing Meditation (a violin piece) on a Yamaha AR100 organ.
I asked Andy Gilbert (
andyg) .. who is a music teacher, has his own Music School, and used to work for Kawai .. what he thought about all this, and his comment is below.