Pianotech

Coincidently, I've been working on a tool or method to eliminate false beats. Just this weekend I tested a prototype tool based upon the premise that false beats are not caused by loose bridge pins. Although my first prototype tools support the idea that the false beat may be due to the gap that develops between the bridge cap and the string, it did not give me conclusive results, though it did reduce the beat frequency where tapping the string down failed.

I have been suspicious of CA curing the false beat problem given my premise of the string gap theory. I suspect (maybe wrong) that CA is not strengthening the bridge pin but is in fact filling the gap that has developed. Also, CA tends to reduce sustain.

My attention diverted from the CA solution based upon years of experience with false beats. I noticed when restring a piano, false beats are eliminated if I remove the bridge pins and sand down the cap and install new pins, but when I restring a piano without sanding down the bridge leaving the original pins and add CA before installing new strings, the false beats are still present.  Another "reveal" I observed is when a string breaks on a relative new piano, such as Yamaha or Kawai, that has no significant false beat problem I encounter false beats with the new string that are difficult or impossible to correct. Is that situation caused by the new string not conforming to the original side-to-side string imprint on the bridge? Maybe, or is the new string not conforming to the established vertical gap from the original string.

My research is moving forward, albeit at a slow pace, with the testing of a tool requiring considerable machining.

If anybody has observed false beat characteristics that cannot be cured with CA and have a plausible theory, let me know. I'm willing to work with you.

I quick note: I'm not looking for solutions that entail a complete redesign of the bridge or scaling. If a brand name piano hasn't displayed false beats when new – and many new pianos are free of false beats - then the problem must certainly point to wear or aging of the bridge or string.

Roger

Coincidently, I've been working on a tool or method to eliminate false beats. Just this weekend I tested a prototype tool based upon the premise that false beats are not caused by loose bridge pins. Although my first prototype tools support the idea that the false beat may be due to the gap that develops between the bridge cap and the string, it did not give me conclusive results, though it did reduce the beat frequency where tapping the string down failed.

I have been suspicious of CA curing the false beat problem given my premise of the string gap theory. I suspect (maybe wrong) that CA is not strengthening the bridge pin but is in fact filling the gap that has developed. Also, CA tends to reduce sustain.

My attention diverted from the CA solution based upon years of experience with false beats. I noticed when restring a piano, false beats are eliminated if I remove the bridge pins and sand down the cap and install new pins, but when I restring a piano without sanding down the bridge leaving the original pins and add CA before installing new strings, the false beats are still present.  Another "reveal" I observed is when a string breaks on a relative new piano, such as Yamaha or Kawai, that has no significant false beat problem I encounter false beats with the new string that are difficult or impossible to correct. Is that situation caused by the new string not conforming to the original side-to-side string imprint on the bridge? Maybe, or is the new string not conforming to the established vertical gap from the original string.

My research is moving forward, albeit at a slow pace, with the testing of a tool requiring considerable machining.

If anybody has observed false beat characteristics that cannot be cured with CA and have a plausible theory, let me know. I'm willing to work with you.

I quick note: I'm not looking for solutions that entail a complete redesign of the bridge or scaling. If a brand name piano hasn't displayed false beats when new – and many new pianos are free of false beats - then the problem must certainly point to wear or aging of the bridge or string.

Roger

Peter and all,

I agree new wire doesn't conform to the established string groves but would hesitate to attribute it to tensile strength being different from the adjacent wires. False beats are a singular phenomenon, and I can't visualize how a static adjacent wire would have an impact on a new wire. But these are speculative.

Impedance is another issue. Understanding the definition of impedance in this situation would be helpful when visualizing the probable cause of false beats. With impedance there is a "reactance" factor to consider. How does a solid object (in this case the bridge) react to the oncoming rush of energy? A pure impedance model would define reactance in terms of the amount of energy reflected back into the speaking length. But in the case of a false beat there seems to be a "skipping" of a certain amount of energy past the bridge pin and onto the bridge cap and then possibly reflected again by the rear bridge pin. This is an unfortunate unique situation with piano bridge terminations where it is not possible to design a steep down-bearing associated with other string instruments such as violins and guitars.

The skipping of energy (if this is what's happening) would suggest there is a "ghost" termination, whether it be the middle of the bridge cap or the rear bridge pin, that reflects energy into the speaking length of the string at a frequency which is slightly different from the primary frequency. Why a new string on a new bridge cap does not exhibit this phenomenon is a bit of a mystery other than to say that a uniform contact area on the new bridge seems to assure that no energy is reflected within the bridge area.

These thoughts are based upon the hypothesis that the developed gap is the cause of false beats. Possibly this hypothesis will be thrown out the door with new information discovered during further investigation.

One last thought. I did get an improved response when slightly bending the wire on the rear duplex section of the string, bolstering the gap theory.

Roger

Coincidently, I've been working on a tool or method to eliminate false beats. Just this weekend I tested a prototype tool based upon the premise that false beats are not caused by loose bridge pins. Although my first prototype tools support the idea that the false beat may be due to the gap that develops between the bridge cap and the string, it did not give me conclusive results, though it did reduce the beat frequency where tapping the string down failed.

I have been suspicious of CA curing the false beat problem given my premise of the string gap theory. I suspect (maybe wrong) that CA is not strengthening the bridge pin but is in fact filling the gap that has developed. Also, CA tends to reduce sustain.

My attention diverted from the CA solution based upon years of experience with false beats. I noticed when restring a piano, false beats are eliminated if I remove the bridge pins and sand down the cap and install new pins, but when I restring a piano without sanding down the bridge leaving the original pins and add CA before installing new strings, the false beats are still present.  Another "reveal" I observed is when a string breaks on a relative new piano, such as Yamaha or Kawai, that has no significant false beat problem I encounter false beats with the new string that are difficult or impossible to correct. Is that situation caused by the new string not conforming to the original side-to-side string imprint on the bridge? Maybe, or is the new string not conforming to the established vertical gap from the original string.

My research is moving forward, albeit at a slow pace, with the testing of a tool requiring considerable machining.

If anybody has observed false beat characteristics that cannot be cured with CA and have a plausible theory, let me know. I'm willing to work with you.

I quick note: I'm not looking for solutions that entail a complete redesign of the bridge or scaling. If a brand name piano hasn't displayed false beats when new – and many new pianos are free of false beats - then the problem must certainly point to wear or aging of the bridge or string.

Roger

Peter and all,

I agree new wire doesn't conform to the established string groves but would hesitate to attribute it to tensile strength being different from the adjacent wires. False beats are a singular phenomenon, and I can't visualize how a static adjacent wire would have an impact on a new wire. But these are speculative.

Impedance is another issue. Understanding the definition of impedance in this situation would be helpful when visualizing the probable cause of false beats. With impedance there is a "reactance" factor to consider. How does a solid object (in this case the bridge) react to the oncoming rush of energy? A pure impedance model would define reactance in terms of the amount of energy reflected back into the speaking length. But in the case of a false beat there seems to be a "skipping" of a certain amount of energy past the bridge pin and onto the bridge cap and then possibly reflected again by the rear bridge pin. This is an unfortunate unique situation with piano bridge terminations where it is not possible to design a steep down-bearing associated with other string instruments such as violins and guitars.

The skipping of energy (if this is what's happening) would suggest there is a "ghost" termination, whether it be the middle of the bridge cap or the rear bridge pin, that reflects energy into the speaking length of the string at a frequency which is slightly different from the primary frequency. Why a new string on a new bridge cap does not exhibit this phenomenon is a bit of a mystery other than to say that a uniform contact area on the new bridge seems to assure that no energy is reflected within the bridge area.

These thoughts are based upon the hypothesis that the developed gap is the cause of false beats. Possibly this hypothesis will be thrown out the door with new information discovered during further investigation.

One last thought. I did get an improved response when slightly bending the wire on the rear duplex section of the string, bolstering the gap theory.

Roger

Coincidently, I've been working on a tool or method to eliminate false beats. Just this weekend I tested a prototype tool based upon the premise that false beats are not caused by loose bridge pins. Although my first prototype tools support the idea that the false beat may be due to the gap that develops between the bridge cap and the string, it did not give me conclusive results, though it did reduce the beat frequency where tapping the string down failed.

I have been suspicious of CA curing the false beat problem given my premise of the string gap theory. I suspect (maybe wrong) that CA is not strengthening the bridge pin but is in fact filling the gap that has developed. Also, CA tends to reduce sustain.

My attention diverted from the CA solution based upon years of experience with false beats. I noticed when restring a piano, false beats are eliminated if I remove the bridge pins and sand down the cap and install new pins, but when I restring a piano without sanding down the bridge leaving the original pins and add CA before installing new strings, the false beats are still present.  Another "reveal" I observed is when a string breaks on a relative new piano, such as Yamaha or Kawai, that has no significant false beat problem I encounter false beats with the new string that are difficult or impossible to correct. Is that situation caused by the new string not conforming to the original side-to-side string imprint on the bridge? Maybe, or is the new string not conforming to the established vertical gap from the original string.

My research is moving forward, albeit at a slow pace, with the testing of a tool requiring considerable machining.

If anybody has observed false beat characteristics that cannot be cured with CA and have a plausible theory, let me know. I'm willing to work with you.

I quick note: I'm not looking for solutions that entail a complete redesign of the bridge or scaling. If a brand name piano hasn't displayed false beats when new – and many new pianos are free of false beats - then the problem must certainly point to wear or aging of the bridge or string.

Roger

Coincidently, I've been working on a tool or method to eliminate false beats. Just this weekend I tested a prototype tool based upon the premise that false beats are not caused by loose bridge pins. Although my first prototype tools support the idea that the false beat may be due to the gap that develops between the bridge cap and the string, it did not give me conclusive results, though it did reduce the beat frequency where tapping the string down failed.

I have been suspicious of CA curing the false beat problem given my premise of the string gap theory. I suspect (maybe wrong) that CA is not strengthening the bridge pin but is in fact filling the gap that has developed. Also, CA tends to reduce sustain.

My attention diverted from the CA solution based upon years of experience with false beats. I noticed when restring a piano, false beats are eliminated if I remove the bridge pins and sand down the cap and install new pins, but when I restring a piano without sanding down the bridge leaving the original pins and add CA before installing new strings, the false beats are still present.  Another "reveal" I observed is when a string breaks on a relative new piano, such as Yamaha or Kawai, that has no significant false beat problem I encounter false beats with the new string that are difficult or impossible to correct. Is that situation caused by the new string not conforming to the original side-to-side string imprint on the bridge? Maybe, or is the new string not conforming to the established vertical gap from the original string.

My research is moving forward, albeit at a slow pace, with the testing of a tool requiring considerable machining.

If anybody has observed false beat characteristics that cannot be cured with CA and have a plausible theory, let me know. I'm willing to work with you.

I quick note: I'm not looking for solutions that entail a complete redesign of the bridge or scaling. If a brand name piano hasn't displayed false beats when new – and many new pianos are free of false beats - then the problem must certainly point to wear or aging of the bridge or string.

Roger

Coincidently, I've been working on a tool or method to eliminate false beats. Just this weekend I tested a prototype tool based upon the premise that false beats are not caused by loose bridge pins. Although my first prototype tools support the idea that the false beat may be due to the gap that develops between the bridge cap and the string, it did not give me conclusive results, though it did reduce the beat frequency where tapping the string down failed.

I have been suspicious of CA curing the false beat problem given my premise of the string gap theory. I suspect (maybe wrong) that CA is not strengthening the bridge pin but is in fact filling the gap that has developed. Also, CA tends to reduce sustain.

My attention diverted from the CA solution based upon years of experience with false beats. I noticed when restring a piano, false beats are eliminated if I remove the bridge pins and sand down the cap and install new pins, but when I restring a piano without sanding down the bridge leaving the original pins and add CA before installing new strings, the false beats are still present.  Another "reveal" I observed is when a string breaks on a relative new piano, such as Yamaha or Kawai, that has no significant false beat problem I encounter false beats with the new string that are difficult or impossible to correct. Is that situation caused by the new string not conforming to the original side-to-side string imprint on the bridge? Maybe, or is the new string not conforming to the established vertical gap from the original string.

My research is moving forward, albeit at a slow pace, with the testing of a tool requiring considerable machining.

If anybody has observed false beat characteristics that cannot be cured with CA and have a plausible theory, let me know. I'm willing to work with you.

I quick note: I'm not looking for solutions that entail a complete redesign of the bridge or scaling. If a brand name piano hasn't displayed false beats when new – and many new pianos are free of false beats - then the problem must certainly point to wear or aging of the bridge or string.

Roger

Coincidently, I've been working on a tool or method to eliminate false beats. Just this weekend I tested a prototype tool based upon the premise that false beats are not caused by loose bridge pins. Although my first prototype tools support the idea that the false beat may be due to the gap that develops between the bridge cap and the string, it did not give me conclusive results, though it did reduce the beat frequency where tapping the string down failed.

I have been suspicious of CA curing the false beat problem given my premise of the string gap theory. I suspect (maybe wrong) that CA is not strengthening the bridge pin but is in fact filling the gap that has developed. Also, CA tends to reduce sustain.

My attention diverted from the CA solution based upon years of experience with false beats. I noticed when restring a piano, false beats are eliminated if I remove the bridge pins and sand down the cap and install new pins, but when I restring a piano without sanding down the bridge leaving the original pins and add CA before installing new strings, the false beats are still present.  Another "reveal" I observed is when a string breaks on a relative new piano, such as Yamaha or Kawai, that has no significant false beat problem I encounter false beats with the new string that are difficult or impossible to correct. Is that situation caused by the new string not conforming to the original side-to-side string imprint on the bridge? Maybe, or is the new string not conforming to the established vertical gap from the original string.

My research is moving forward, albeit at a slow pace, with the testing of a tool requiring considerable machining.

If anybody has observed false beat characteristics that cannot be cured with CA and have a plausible theory, let me know. I'm willing to work with you.

I quick note: I'm not looking for solutions that entail a complete redesign of the bridge or scaling. If a brand name piano hasn't displayed false beats when new – and many new pianos are free of false beats - then the problem must certainly point to wear or aging of the bridge or string.

Roger