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 | | |
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