I thought the recent discussions were about whether a tuned duplex was worth much, not so much whether the duplex itself should be open or not. I have had similar experiences in which the capo section duplexes were braided and removing the braid seemed to have some effect. Similarly, I've had experiences where the tenor and bass backscales were unbraided and were making too much noise vibrating sympathetically when unwanted. There does seem to be a crossover point where the free and sympathetic duplex is loud enough to be "sensed" but not so loud as to be heard, if you catch my meaning. It seems pretty clear that the duplex or backscale area is an area that can and does respond sympathetically. The question of whether it's important that it's tuned or not is another matter. Did you happen to test whether or not they were tuned? 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 BobDavis88 at aol.com Sent: Tuesday, November 13, 2007 10:41 PM To: pianotech at ptg.org Subject: Re: The Duplex affect --an experiement In a message dated 11/13/2007 9:50:57 PM Pacific Standard Time, davidlovepianos at comcast.net writes: Did you do the experiment blind? i.e. did the listeners (and player) know when the tape was on or off? You need to do that to really legitimize the results. David, It was at the end of the meeting, so it was somewhat ad hoc. However, I suggested the exercise because of my own experiments in this area, and because I didn't agree with recent talk about the duplexes not being worth much. The first piano on which I had practical use for it was a Steinway D some years ago that had been braided all the way up the tenor at the factory. There was something unsatisfactory about the tone, and I was poking around, and noticed the braiding. I pulled it out and was surprised at the improvement. Back to our meeting - We found that the difference with/without the tape in the tenor was so obvious that I have no doubt what the results would be not looking. The differences in the other sections were more subtle, and I too would like to repeat them with more controls. Our sense was that the tone just sounded freer, bigger, and more interesting with the duplexes open, even the upper ones, but I'd be happy to try it again when we have more time. It brought up the question of whether the duplexes were compensating for poor soundboard design. This would be a hard one to control for, but my off-the-cuff feeling was that a more efficient soundboard would just make the effect more obvious. Piano tone relies on the interaction of so many things that it's hard to change just one, and be satisfied that we have enough information to draw useful conclusions. Other variables in the duplex experiment might be the distance from the piano at which the sound change was noticeable, and the effect of hammer voicing, and the phase of the moon, and.... Bob Davis _____ See what's new at AOL.com <http://www.aol.com?NCID=AOLCMP00300000001170> and Make AOL Your <http://www.aol.com/mksplash.adp?NCID=AOLCMP00300000001169> Homepage. -------------- next part -------------- An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/20071114/a390c9de/attachment.html
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