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Hi
I have tuned my Grotrian Steinweg Mod. Concertino upright a few days ago. The piano is about 20 years old and has, unfortunately some strings with false beats from the midrange to the treble.
I tried to seat whatever is possible to seat, nothing really helped. I made two records of two notes, A4 and F#6.

I add the soundcloud links here:

http://snd.sc/13i374L

http://snd.sc/13i49xD

Do you know some more tricks to "clean up" a single string?
Other possiblities I heard about is a new string, or turn the bridge pin a litte bit.
I am not really happy with unisons like that.

Thanks

PS. while checking the soundfiles I heard, that in reality it sounds a little bader

Did you try: Tune the good strings first and tune the false beat (by ear) to blend.

The best thing to do would be to figure out what is causing the false beat.

The only two things that I can think of that cause false beats are poor terminations, and imperfections in the string. Anyone else think of any?

I find most false beats coming from the bridge pin, but others may have other experience.

Regards,

Replacing the string rarely has the effect of reducing false beats. I think string imperfections are fairly rare, unless the string has been compromised, for example by raising the pitch much too high, which can lead to goose-necking.

It could be an artifact of the recording that I am hearing-but the slap noise of the hammer impact seems long in duration. Did you replace the hammers?

False beats are not totally understood. In the high treble the things that can reduce them are; having the V-bar shaped to a definite V, Having the string path across the V-bar to the tuning pin as straight as possible, having tight in the wood bridge pins, having the motion of the hammer while striking the string at 90 degrees to the string plane, having the hammer center firm, having the hammer excite all unison string at precisely the same time.

Hope this helps

the first measure I use is always to look closely at the bend where the wire get out of the bridge pin.

The shine on the wire show often that the bend extend a little far and it can be straightened by massaging.

Many false beats respond to that, but not all.
On capo sections, I also use a thinned pedal rod (in brass) and tap the wire at 45° one tap from both side, expecting the wire to "bed" differntly (tapping from the speaking lenght side)

The thinned part acts as a fulcrum and release the pressure for a small moment at impact.
Same tool used to move the strings (from below then, generally)

on your F# the middle string have also a beat, may be only due to the left string.
Did you check the backlenght ? it may be creating the beat.

I know nothing about unisons but i guess you could have more sound projection, more "activity" it is a little cold, to me.

The exact moment wher the strings begin to couple (phase) can be tuned clean. when tuning a little later the energy of the attack is less tuned. I know we do not think or hear that energy when we tune, at first, because what annoy us are beats and they are easy to clean beginning with the top spectra.

I learned to tune the "jump" of the tone. With pianos that are very lively as that one you have anyway some energy at the attack, but some may miss a little (Yamahas, for instance) and then that work on the enveloppe is very necessary.

The basis is to hear a sound "oH" projected , that is the decay coupling. Then the spectra is also "combed" but some attention is needed for both. That energy (assuming voicing is decent) is felt in the handle of the tuning lever, as well as in the finger that play the note.

To be aware of that, ask a friend to play the note while you manipulate the lever, and realize what misses you.
If your friend is a tuner you can make the opposite, play and have him hold the lever... a real eye opener (not much in favor of key strikers, but they also provide some sensation, even if less large)

Your test blows are perfect

Jurgen I had a totally opposite point of view, based on partial analysis. I know strings are supposed to be homogeneous, but there are too much differences between the spectra of the same note for it to be possible.
May be the differences in spectras are only on the bends or due to backscales and strike point, I do not know.

Hammer to string contact? Are all the strings getting a fair whack from the hammer? Sometimes the 'false' beast (...not a spelling error) comes from a string in the unison that is not properly mated to the hammer.

Rotate the hammer to the strings and pluck. Align the string that is not mated properly. Sometimes you need to file a single string groove. Jurgen at Forte has a nice single-string sanding paddle.
<<Jurgen Goering
Piano Forte Supply
www.pianofortesupply.com>>

Seating?
You mention seating, but have you tried slightly shifting/re-postioning the wire? Olek also points out a place where I've had some success in killing false beasts; a slight pull/adjust of the wire as it leaves the bridge-pin may help. A string hook or brass tool and a gentle pull to seat the string at the bridge-pin and remove the curve. Works. Sometimes.
(sigh)

Do NOT rotate the bridge-pin to look for a change! You will loosen the bridge-pin, and may actually cause a new problem. I have heard of tapping bridge-pins to insure they are seated, but have never heard of turning them. I did once have a kawai grand where the bridge-pins were loose, and actually walked up, away from the bridge with the string, but cured that with a tap, and a shot of CA-glue at the base of the pins. Still good after 15 years, that one is. But...extreme and rare.

Good Luck, sir!
Respectfully,

Fascinating. This is the same flaw, if you will, that I have in a 1992 Kohler & Campbell grand (SKG 600) I take care of. In the upper third of the piano the unisons have pretty strong false beating which requires far more attention in tuning. Seating the strings on the bridge really didn't achieve much. I did observe, in my situation, rather irregular notching of the bridge where some were notched slightly short or slightly long in relation to the bridge pins of each individual speaking length. I haven't done much fussing with basic prep that has probably never been done but I am skeptical of the less than perfect bridge.

Especially if you tune aurally, it is wise to first check things in the home that might create the perception of false beats, before effecting changes in the piano. If there are ceiling fans and portable fans in the area, be sure these are turned off. If you still hear false beats, then focus on the instrument.

Hold a metal screwdriver or some other object against the bridge pin of the offending note. This will often temporarily suppress the false beat. If it does, then you know you have a problem with the bridge pin, or the bridge. Look for cracks at the hole. Tap the pin, see if you can make it sit better. Or the best thing would be to wick a little thin CA glue (thin superglue, very low viscosity) into the hole.

Anybody know what to do if you can suppress a false beat by pressing on the bridge pin, but you can't cure it with the above methods?

The CA trick may work but bridge pins are not always tapped in the wood, because due to seasonal wood movement they can go out if they are used as nails. (mostly when wood retract at winter)

If I tap them I do not want them to go deeper than they where before, for that reason.

Phil D, I found this to be true with my K&C grand checking it last night, every false beating note. The remarkable thing is that it took no pressure at all against the bridge pin terminating the speaking length to make it disappear. Just very gently resting my brass string seating rod next to the pin did the trick.

Is CA the only option here or is a slightly larger bridge pin (perhaps with an epoxy, etc.) a conceivable way to go? Coaxing of the wire at termination points only helped a few strings and very minimally. Actually a few plays of those strings caused the beating to return.

How I would love to have a clean treble with minimal false beating... for tuning sake if nothing else.

I'll add burnishing the V-bar. (Grand treble and upright tenor to treble.) Use a screwdriver and slide the string side to side. You will hear a definitive "click" as the string jumps out of its groove it has created in the v-bar. As you slide the string side to side, the clicking gets less as the groove is burnished (filed) by the string. Sometimes after this procedure there are still false beats. Then I try moving the string arouind a bit to find the spot with the least false beat.

Marc, I would not use the wire to "file" the capo, nor a steel blade on the wire (that last just by principle, but that way I was taught)

there are thin diamant limes, but in a hurry re seating the wire may be enough.

All the tools to manipulate the wire are in brass. (or in wood)

Try to make a nick on a wire, and use a magnifier to see how easy it is.

Being a teatcher I believe you should not instruct those sort of tricks, the wire may even broke, later it is yet fragile at that location.

Greetings,
You will need to redrill the bridge to go up a pin size. I do it when restringing calls for it, but I have found that wicking thin CA down into the bridge alongside the pin will often help. Changing the wire is also necessary on many new "Standard" pianos, as it seems the strong-arms in the chipping/tuning departments overstress a lot of the strings.
Orientation of the string's curvature when installing has also been shown to be a factor in false beats, so it is possible that giving a plain wire a twist and then reinstalling it might obviate the beating.
Regards,

Thanks for all the suggestions. I will try and see, if it works on my piano. I think, I have read the thing with turning the bridge pin in the book of Ulrich Laible, but I am not exactely sure.
In the case of false beats I tune first the right string, witch has often nearely no false beats. And sometimes, the false beats dissapear when all three strings are in tune, don't know why, but that should happen more often.

Thanks again to all!!