From bruce@ashbysolutions.com Sun Dec 30 12:41:15 2001
Subject:Re: drawbar question: why is 5 1/3 not between 8' and 4'?

Vali,

>After a while he asked me: But daddy, why is 5_1/3 as an exception
>not in ascending line? And why is it brown and not black like the
>other "odd" numbers?
>
>And, to close my questions: why is 16' not white like 8+4+2+1?

The brown drawbars are considered sub-harmonics of the 8' drawbar -- the organ "standard" for fundamental tones. So the easy question: Why is the 16' brown? Because it's a sub-harmonic.

The 5 1/3' is a little less obvious. There is an acoustic phenomenon where playing two harmonics causes the ear to "hear" the fundamental -- even when it's not there! This is what allows one to hear bass out of a cheap radio with a 3" or 4" speaker. The speaker cannot produce 80Hz, but the presence of 160Hz, 240Hz, etc. causes the brain to add the fundamental to the sound. 5 1/3' is the third harmonic of 16', so it's classified as a sub-harmonic, too.

Regards,

-BW

--
Bruce Wahler
Design Consultant
Ashby Solutions™ http://consult.ashbysolutions.com
CloneWheel Support Group and HiNote moderator
978.386.7389 voice/fax
bruce@ashbysolutions.com