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The Kawai KG 1C grand that I have repinned and restrung has a couple of strings beating on it at D#3, the last note on the tenor bridge before the tenor/bass cross over.

Two out of the 3 string unison are beating quite prominently at slightly different rates, the slowest at about 2bps. The 3rd string of the unison sounds good/clean.

It is impossible to tune the D#3 so that it sounds decent.

Your help would be much appreciated.

Thank you.

I've seen loose bridge pins on a few of these pianos. You can check by holding a screwdriver blade on the speaking side pin. You'll need someone to assist. If the beating stops, then I'd suspect they're loose.

Tim

not suspicion at that point CA help there, apparently.

false beats can be the result of a long backscale somewhere also, but if only on 2 strings of an unison, I would change them.

Thank you Tim for the tip. I will try it out.

Best regards,

I've never witnessed loose bridge pins causing causing false beats. The theory seems sound, but I've never experienced it. If the screwdriver, or properly positioned vice grips, don't solve the problem, I would deduce the problem is a twist in the wire (ie the way in which you installed it). I would absolutely replace the wire.

Hello A443

How often do you come across loose bridge pins?

What are the results/consequences of loose bridge pins?

What do you do to rectify the problem of loose bridge pins?

Thank you.

That's just it: I don't often come across loose bridge pins, and when I do, it also doesn't necessarily result in a false beat.

IF the bridge pin is the problem, then carefully setup some vice grips on the pins, and see if the problem goes away completely. ONLY then, would I assume it has something to do with the bridge pin. Otherwise, the problem is elsewhere (i.e., the string).

Resolving a loose bridge pin issue is a compromise, no matter what you do. I tend to want to repair the size of the hole by plugging it and re-drilling it...but this is complicated and time-consuming to do it well. The other thing to do is put a bigger bridge pin in. I tend to shy away from CA glues and the like. Maybe it is ok for a cheap piano that is already dead and gone, but otherwise, I don't know what the long term effects are--so I remain conservative on the issue.

something can quieten false beats it is to straighten the string just out of the bridge pin. o not know why but it help.

plugging in such small place is probably not efficient.

CA seem to fix somewhat the pin, an probably does not cause trouble if thicker ones are use later.

On a cheap piano, epoxy can reinforce correctly the wood (impregnation, then adding a thicker one) easily make a mess at the surface, the good quality must be used.

I do think that one of the affects of loose bridge pins is false beats, though I am aware that some folks, like yourself A443, do not think so.

Until proven otherwise, I will hold to this opinion.

Thank you.

Well, please take the time to observe, think, and prove yourself otherwise (i.e., instead of simply holding on to a belief that you've pickup somewhere).

I am proving you otherwise right now, but because you haven't taken the time to make your own observations, you don't really get what is going on--it's not up to other people to prove anything to you; you have to do the observations yourself.

If you stabilise the so called false-beats-causing bridge pins with a pair of vice grips, a screwdriver, or what ever your brain can come up with, and there is still is false beat, what does that tell you?!? How could the bridge pin, when it is being temporarily stabilised, still cause a false beat problem? If you can come up with a possibility, then eliminate that too, until your false beat goes away. If it never does, the problem might just be with your way of thinking.

Yes, ok, A443, I will look into things better.

Also, I did say I would try it out, so your accusation of me not willing to investigate or look into the matter is false. A lot of what I know and do is from investigation, trial and error.

Since you say you will take the time to investigate sometime in the future, you might as well take a few notes that are perfectly straight (i.e., with no false beats) and temporarily replace those bridge pins with smaller ones (i.e., ones that are going to be loose). If you really want to know how to fix false beats, you need to also know how to cause them.

I have just re read your earlier post A443.

My apologies, I have misread and misinterpreted.

Please accept my sincere apologies for the run around.

On re reading your earlier post, I think that I will look and see if the wire is twisted, after trying the screw driver trick on the bridge pins.

Thank you for your posts and time.

Best regards,

Before nailing this on a false beat, you could be dealing with a wayward longitudinal mode?

Mute 2 strings leaving one of the beating strings. Note the speed of the self-beating. Change the pitch of the string and note the speed of the beats. If the beat speed does not change at different frequencies, the mess is caused by a longitinal mode, which can only be changed by changing the speaking length.

Jim Ialeggio

Are you sure about that? I thought longitudinal modes were an order of magnitude higher than the first partial. Mark said the false beats were about 2 bps. D#3 ( appox. 155.5 Hz ) would have a longitudinal mode of over 1500 Hz and would have to beat with a very strong 10th partial to hear the beats.

Don't know...maybe I'm showing my ignorance on this subject...but to tell you the truth, I can't say I ever have dealt with false beats down there. Noisy strings, yes, but I don't think they were self-beating.

Jim Ialeggio

I would imagine these are plain wire? With most false beating after restringing one should check both termination points. If this goes through an agraffe did you ream it out slightly? Old string impressions can change or interfere with the front termination and speaking length.

Thank you Jim and SM Haley.

Thank you to all for your thoughts on the matter.

I am going to look into it.

I may not have much to add, Mark.

False beats are almost unheard of on plain wire strings that low. My only thought is really poor hammer pining and mating. That can make things go bad. Like the hammer hitting one string obliquely first, then scuffing into another or something.

Not everything is solvable...