I believe this requires 12" to be removed at the main tuning slide (6" each leg) but I have no idea what happens at the

1st, 2nd & 3rd valve tuning slides. How is this calculate please.

Basically, per leg it's 6" in the cylindrical TS, 3/4 for the 1st valve, 3/8 for the 2nd, and 1 1/8 for the 3rd.

If you're interested... the equal temperament semitone ratio is 1:2^(1/12), thus 2^(2/12) for a whole tone, very close to the just major tone ratio of 9:8.

<TABLE>[table]
<TR>[tr]
<TD>[td]</TD>
<TD>[td]Bb</TD>
<TD>[td]C</TD>
<TD>[td]difference</TD>
<TD>[td]per leg</TD>
</TR>
<TR>[tr]
<TD>[td]open</TD>
<TD>[td]108</TD>
<TD>[td]96</TD>
<TD>[td]12</TD>
<TD>[td]6</TD>
</TR>
<TR>[tr]
<TD>[td]1st</TD>
<TD>[td]13.226</TD>
<TD>[td]11.756</TD>
<TD>[td]1.470</TD>
<TD>[td]0.735</TD>
</TR>
<TR>[tr]
<TD>[td]2nd</TD>
<TD>[td]6.422</TD>
<TD>[td]5.708</TD>
<TD>[td]0.714</TD>
<TD>[td]0.357</TD>
</TR>
<TR>[tr]
<TD>[td]3rd</TD>
<TD>[td]20.434</TD>
<TD>[td]18.164</TD>
<TD>[td]2.270</TD>
<TD>[td]1.135</TD>
</TR>
</TABLE>

THANK YOU. THAT'S GREAT.