The bridge adds stiffness and mass to the system which raises the impedance. I think it raises the impedance too much on those pianos because that's what I hear. I don't really calculate the bridge contribution to the system but I have a preferred minimum and maximum based on my own experience. The MH bridge exceeds my preferred maximum and the sound that I hear reflects that. I suppose bridge characteristics can vary with ribs, panel thickness (and scales, for that matter) but I don't think you should substitute bridge height for rib dimensions or panel thickness. For me, rib scales and panel thickness are related to string scale (downbearing), size of the piano, number of ribs (of course), . I don't really see that the bridge should vary that much. I think you will get different answers from different people as to what they think is the best combination for the treble bridge based on their own tonal preference and where in the treble bridge you are talking about. This piano (MH) has a bridge that at C88 is 40 mm wide and 37 mm tall. Compare that with a Steinway B also in my shop now that has abridge that is 33 mm wide and 30 mm tall. I would say that the difference in bridge dimensions will account for some tonal differences. The MH has a slightly higher tension scale but not enough to explain the need for a bridge that much larger. Of course, you can make a system which is too high in impedance any number of ways: ribs, panel, bridge. But there probably is some ideal combination. So far, left to my own devices, I prefer a bridge of somewhat smaller dimensions. My method of calculating rib scales is not, or at least I prefer that not be, bridge dependent. David Love www.davidlovepianos.com From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Encore Pianos Sent: Thursday, November 01, 2012 3:31 PM To: pianotech at ptg.org Subject: Re: [pianotech] cutting down a MH bridge How does it raise the impedence characteristics too much? Why do you think it raises the impedence characteristics too much? How much is too much and how much is just enough? Since we are dealing with mass and stiffness, what would be the best combination for a treble bridge? Should those characteristics for a bridge vary from piano to piano, depending on the ribbing, panel thickness, etc. etc.? Will Truitt From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of David Love Sent: Thursday, November 01, 2012 6:08 PM To: pianotech at ptg.org Subject: Re: [pianotech] cutting down a MH bridge I didn't state but I have always felt that the MH bridge was too massive and raised the impedance characteristics too much. David Love www.davidlovepianos.com From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Dale Erwin Sent: Thursday, November 01, 2012 2:33 PM To: pianotech at ptg.org Subject: Re: [pianotech] cutting down a MH bridge Did I miss why you want to cut it down /remove mass Dale Erwin R.P.T. Erwin's Piano Restoration Inc. Mason & Hamlin/Steinway/U.S. pianos www.Erwinspiano.com Phone: 209-577-8397 -----Original Message----- From: David Love <davidlovepianos at comcast.net> To: pianotech <pianotech at ptg.org> Sent: Thu, Nov 1, 2012 12:45 pm Subject: Re: [pianotech] cutting down a MH bridge Or possibly a router. I was trying to figure out how to build and position a guide so as to keep the cut a constant width through the curves without having to freehand it. David Love www.davidlovepianos.com -----Original Message----- From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org <mailto:pianotech-bounces at ptg.org?> ] On Behalf Of Terry Farrell Sent: Thursday, November 01, 2012 12:06 PM To: pianotech at ptg.org Subject: Re: [pianotech] cutting down a MH bridge I'll second what Ron said. And if you do go that route, I know a guy in Florida that makes beautiful laminated bridges. But if I were going to use the original, then yeah, I'd fire up the bandsaw. You should be able to saw it pretty smooth freehand. Or you could make some sort of post on your fence (like a several inch bump - maybe a vertical board of maple rounded on the end at a right angle to the fence) right at the blade - that way you would have a guide for constant thickness and yet it would allow you to change the orientation of the bridge as you go along the curve. You'd probably have to do the doglegs freehand though. Let me know if I can help you. Terry Farrell On Nov 1, 2012, at 2:18 PM, Ron Nossaman wrote: > On 11/1/2012 12:40 PM, David Love wrote: >> I'm putting a new board in a MH piano (AA) and considering trimming >> that massive 40 mm wide bridge to something more reasonable like >> 33mm. Has anyone ever done that? What was your method other than >> careful band saw and a lot of sanding? > > Make a new one. You'll even get the chance to make a better length progression across the breaks. > Ron N > -------------- next part -------------- An HTML attachment was scrubbed... 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