Mechanical Music Digest  Archives
You Are Not Logged In Login/Get New Account
Please Log In. Accounts are free!
Logged In users are granted additional features including a more current version of the Archives and a simplified process for submitting articles.
Home Archives Calendar Gallery Store Links Info
MMD > Archives > November 2014 > 2014.11.11 > 08Prev  Next


Regulating the Duo-Art Expression System
By Julian Dyer

The reason that any spring-operated regulator plays too loudly is that
the spring tension is too high for the given expression coding.  In a
Duo-Art, it's easy to get the zero level right, but if the spring has
too high an initial tension the expression will pull away too fast as
the spring is stretched.  Aeolian said that the spring should be "just
loose" at rest, or something like that.  That means the initial tension
in the spring is nil.

When the regulator closes and stretches the spring, the idea is that
the stretch from rest to zero position will give the correct tension
for the zero level.  The approach I've adopted is to alter how far the
regulator rises up to zero level.  Although this is stated as being half
an inch, there is range in the system to make this a bit more or less.
If you want the dynamic range to be a bit lower, fitting a weaker
spring and having the regulator rise a bit further to zero will do the
job nicely.  This is more in keeping with the design of the system than
reducing accordion travel.

Spring tension goes up as the cube of the wire gauge, so switching
between available standard springs of 0.047 and 0.055" is a large leap.
A more subtle way to reduce spring rate is to increase the free length
of the spring, such as by extending the bracket that anchors it.  A
friend did this successfully with a Steinway grand in a small room.
The additional piece just bolted to the end of the T-piece that holds
the springs, and could easily be removed.

Julian Dyer


(Message sent Tue 11 Nov 2014, 06:11:29 GMT, from time zone GMT+0100.)

Key Words in Subject:  Duo-Art, Expression, Regulating, System

Home    Archives    Calendar    Gallery    Store    Links    Info   


Enter text below to search the MMD Website with Google



CONTACT FORM: Click HERE to write to the editor, or to post a message about Mechanical Musical Instruments to the MMD

Unless otherwise noted, all opinions are those of the individual authors and may not represent those of the editors. Compilation copyright 1995-2018 by Jody Kravitz.

Please read our Republication Policy before copying information from or creating links to this web site.

Click HERE to contact the webmaster regarding problems with the website.

Please support publication of the MMD by donating online

Pay via PayPal

No PayPal account required

                                                       
Translate This Page

. .