The strength of the sound a string generates is in its amplitude (the distance from peak-to-peak as measured with an oscilloscope). Two or three wires tuned to exactly the same frequency will, being in phase, reinforce each other and sound louder to the ear and on an oscilloscope. If one string in a bichord is slightly off tune to the other then a heterodyne effect is created where the off-tuned string actually detracts from the amplitude of the combined string combination and can be heard as a "beating" sound. The beating can be hardly noticeable (i.e., very slow) to rapid. The beats are a result of the two string frequencies combining in a non-linear medium (the strings themselves) and creating a difference frequency (the beats) which is a difference of the two individual string frequencies. This difference frequency actually acts as an out-of-phase component and reduces the combined amplitude of the two individual strings, thus making the overall amplitude less. The effect is even more pronounced on a trichord. In actuality, though, tuning a bichord or trichord will result in an overall increase in amplitude but it will be a bit less than if the two or three strings were perfectly in tune (in phase). Tom -----Original Message----- From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Piano Boutique Sent: Thursday, December 30, 2010 4:30 PM To: pianotech at ptg.org Subject: Re: [pianotech] Louder, after tuning? (simplified) Keith, I guess I should have said that the strings transfer to the sound board vie the bridge, but I am a simple kind of guy. William ----- Original Message ----- From: "Mr. Mac's" <tune-repair at allegiance.tv> To: <pianotech at ptg.org> Sent: Thursday, December 30, 2010 3:03 PM Subject: Re: [pianotech] Louder, after tuning? (simplified) On Dec 30, 2010, at 1:34 PM, Piano Boutique wrote: > keith; It is my understanding that two strings in tune are lowder. They > move together and show louder patterns on a DB meater. By working > together; they move more air.; Two strings out of tune have more disanence > and are harsher on the ear drum; which would confuse the human; but shows > not as lowd on a meater.; This is just what I have ben told and i give it > you in good faith.; William Benjamin; PTG RPT Very interesting information you have presented, William. Perceptions are so individual, yet, apparently not so on a measuring device as you have indicated. Thank you so much for sharing as you have done. Keith=
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