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Catalog of Automatic Musical Instrument Scales
By Harald Mueller

Yesterday, I wrote:

> [The repetition distance is] around 4.2 mm on well-kept 20ers ...

and Robbie concluded:

>  [ Wolfgang Brommer told me the paper of 20er music rolls, pulled
>  [ at constant speed by a capstan, typically moves at 60 to 70 mm
>  [ per second.  70/4.2 = 16.7 notes per second.  That's speedy!

But my remark was at least unclear (and, therefore, so are the
repetition distances in the small-organ scales on MMD): By my
definition, the "repetition distance" is from the _end_ of one hole
to the _beginning_ of the next.  So, with a standard hole diameter
on 20ers of 3.0mm, you get about 70/(3.0+4.2) = 9.8 notes per second.

And Robbie is of course correct that this _distance_ is of no use
to the arranger if the _speed_ of the paper strip or carton is not
defined.  Therefore, a _repetition time_ might be more practical.
However, for all organs I know, the speed is actually quite well
defined.

(The large range of 60 to 70 mm per second given for the 20er is more
an exception than the rule; also, as far as I know, not many people
punch 20er rolls with 70 mm per second -- but Jäger and Brommer do so).

Regards
Harald Müller

 [ If 70 mm per second is the _exception_, then, pray tell, what is
 [ the well-defined speed of the _rule?_  ;-)  -- Robbie


(Message sent Tue 16 Sep 2008, 06:38:35 GMT, from time zone GMT+0200.)

Key Words in Subject:  Automatic, Catalog, Instrument, Musical, Scales
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