Brian,
The "drawbars" are a fascinating subject. The 'standard' arrangement of the drawbars on an organ is as below.
But for some reason, best known to themselves, on the AR 80 and 100 organs Yamaha decided to have
their own order for the drawbars and changed round the position of the 5-1/3 ' and the 8'. So we have 16', then 8' and then the 5-1/3 '. Now this may not seem significant, but when they give you a 'recommended' Registration for the position of drawbars for a piece, they just give you numbers, which indicate how far each drawbar should be pulled out.
For example, this
String Ensemble set-up below would be given on a sheet of music as:
4 0 5 5 4 5 3 3 6Clearly, if we set this up on the AR from the numbers given on the sheet of music we would have zero 8' and 5 of 5-1/3 , which would give completely the wrong sound. Also, my AR 80 is missing one of those Drawbars .. the 1-3/5, so I have to be very careful if I set up drawbars according to written numbers. Have to get my brain working!
Now the position of drawbars supposedly gives you the specific 'sound' of an instrument (eg. clarinet, piano, oboe, horn, trumpet etc.), and they used to use the drawbars in this way in the days before they 'digitally sampled' actual instruments and got far better representations for these instruments. If you click this LINK below (do a right-click to open it up in a New Tab) you will see what they used to do. Click on any 'instrument' in the list (eg. String Ensemble) and you will see the drawbar postions for getting this sound (String Ensemble is the example I have given above).
http://keyboardservice.com/Drawbars.aspFor a clear explanation of how the drawbars are used to create the various 'Hammond' sounds, take a look at the Video by Peter Hayward in my next post.
Hugh