Bass Bridge Position

[David Ilvedson]

Conservatives...

David Ilvedson, RPT
Pacifica, CA  94044

----- Original message ----------------------------------------
From: "Greg Newell" <gnewell at ameritech.net>
To: "Pianotech List" <pianotech at ptg.org>
Received: 3/10/2008 7:15:19 PM
Subject: RE: Bass Bridge Position


>Ok, something weird just happened. I started a question/response and it
>disappeared or accidently sent or something suspicious like that. Anyway, my
>questions was why the 5 notes on the trans bridge made life easier for the
>tuner. In scaling I've understood that the primary factor is a smooth line
>for tension. Are you, in this area, favoring a smooth progression of
>inharmonicity rather than tension or impedance?

>Greg Newell
>Greg's Piano Forté
>www.gregspianoforte.com
>216-226-3791 (office)
>216-470-8634 (mobile)


>-----Original Message-----
>From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
>Of Delwin D Fandrich
>Sent: Monday, March 10, 2008 6:26 PM
>To: 'Pianotech List'
>Subject: RE: Bass Bridge Position

>David,

>My current Model O scaling calls for five notes on the transition bridge
>(making
>life easier for the tuner), 12 notes of wrapped mono-chords and 14 notes of
>wrapped bi-chords. I have two scales in my records that are now my
>standards.
>One has an A-1 speaking length of 1325 mm, the other is 1300 mm. I prefer
>the
>latter if everything works out and the phase of the moon is just right.

>And, yes, the extra backscale length is worth going after.

>Del
>Delwin D Fandrich
>Piano Design & Manufacturing Consultant
>620 South Tower Avenue
>Centralia, Washington 98531  USA
>Phone  360.736-7563
><mailto:fandrich at pianobuilders.com> 

>| -----Original Message-----
>| From: pianotech-bounces at ptg.org 
>| [mailto:pianotech-bounces at ptg.org] On Behalf Of David Love
>| Sent: March 10, 2008 9:21 AM
>| To: 'Pianotech List'
>| Subject: RE: Bass Bridge Position
>| 
>| I'll look at that again.  At the moment I have the transition 
>| 27 - 32 with
>| 32 at 850mm and 27 at 975 (F33 is 935).  A#2 (note 26) is at 
>| 896 and A0 is 1320.  As I mentioned, I could move the bass 
>| bridge a bit more forward and gain maybe 15 or 20 mm of 
>| backscale length.  Putting the transition up to note 32 
>| definitely gets the bottom of the tenor bridge away from the 
>| bottom of the bass bridge. 
>| 
>| The overall tension on this piano is about 37000lbs and I've 
>| tried to keep it down there as it's an older O without the 
>| cross strut between the tenor and bass long struts (on the 
>| plate).  Not sure if that's a factor but plate failure is 
>| something I don't care to think about.  I've smoothed it out 
>| but kept the plain wire tensions in the mid 150s drifting 
>| only slightly higher at the upper end.  
>| 
>| David Love
>| davidlovepianos at comcast.net
>| www.davidlovepianos.com
>| 
>| -----Original Message-----
>| From: pianotech-bounces at ptg.org 
>| [mailto:pianotech-bounces at ptg.org] On Behalf Of Ron Nossaman
>| Sent: Sunday, March 09, 2008 8:37 PM
>| To: Pianotech List
>| Subject: Re: Bass Bridge Position
>| 
>| 
>| > Looking at it again I could actually move it up fairly 
>| easily without 
>| > any plate grinding since there is a bit of room from where 
>| A0 crosses 
>| > and the end of the bridge.  My scale experiments suggest that this 
>| > scale looks a
>| bit
>| > better with 12 or 13 monochords in the bass instead of 10.  I'd be 
>| > curious to know how many notes on your transition and what the 
>| > speaking lengths at the beginning and end were.
>| > 
>| > David Love
>| 
>| I left the monochords at ten, and ended up with an A-0 length 
>| of 1308mm, and transition lengths of 987 at B-2. and 932 at 
>| D-3. Four notes. It worked real pretty in the spreadsheet, 
>| and the bridge placement and lengths sound (so far) like I 
>| won't need any mass loading or even voicing to smooth the 
>| transition. It's very smooth right out of the box, and I 
>| don't even have the hammers squared up and strings mated to 
>| them yet. I seem to have come pretty close.
>| 
>| Ron N
>| 
>| 
>|