Pulsating, Wavering, Undulating Strings

Posted by: Anonymous

Pulsating, Wavering, Undulating Strings - 02/17/05 10:26 AM

I'm sure this is a well-worn question, but I'll ask it anyway. How in the world do you get rid of a bunch of false beats in the upper strings of a 100 year-old upright?

Trying to tune three strings together is next to impossible. Each string is a wavering, pulsating, undulating piece of steel wire. Itís crazy.
Posted by: Piano Guy

Re: Pulsating, Wavering, Undulating Strings - 02/17/05 11:18 AM

You need to look at the bridge in the upper treble. Check for cracking along the bridge pin line. If no cracks try a small brass rod and try and seat the offending strings tightly on the bridge. Check for adequate side bearing. You might have to repair the crack and re-set the bridge pins. Are you experianced??
Posted by: JIMBOB

Re: Pulsating, Wavering, Undulating Strings - 02/17/05 12:26 PM

How is the tuning pin torque ? You may be fighting a losing battle if the pin torque is under 48 inch lbs. What about the tuning pin height and condition of the strings and hammers ?
In the end you may need to replace the strings but some light hammer filing and shaping may help. You may want to try replacing a few strings to see what happens. Make sure you mic the strings to make sure you have the right gauge.
Posted by: Brian Lawson, RPT

Re: Pulsating, Wavering, Undulating Strings - 02/17/05 12:53 PM

Also, put some CA glue on the bridge pins, as it is a 100 year old piano. Maybe a few applications, then drop each string slightly to break any glue between the string, bridge & pin.
Posted by: Larry Buck

Re: Pulsating, Wavering, Undulating Strings - 02/17/05 02:06 PM

Hi Rod,

Old strings or strings of poor quality can have this charactaristic.

After you have checked the bridge for damage, seated the strings into the bridge (excessive need for seating can point to bearing issues), you can check for sympathetic interference by muting off the strings between the bridge and hitch pins.

Beyond that, it is not uncommon for the strings to be just plain.....bad.

This can be checked by replacing a couple as to get three new unisions.

If it tunes cleanly.....there it is.

Once again, it is a common problem in old uprights and uprights of poorer quality for the the strings to have "false beats"
Posted by: Keith Roberts

Re: Pulsating, Wavering, Undulating Strings - 02/18/05 06:47 AM

The bridge pins, tap them down. A drop of CA glue.

kpiano
Posted by: BDB

Re: Pulsating, Wavering, Undulating Strings - 02/18/05 09:19 AM

You need to learn how to tune imperfect strings. Life is not as neat as you would like.
Posted by: Sam Casey

Re: Pulsating, Wavering, Undulating Strings - 02/19/05 09:28 AM

Think first of the dollar-value ratio. You've got a $50 piano. In the customer's best interest how much should they invest in dinking around with bridges, pressure bars, flattend strings etc.? Hammers are probably worn to the wood, bearing uneven, bridge wedged against the plate, board cracked in a zillion places, block weak and a half step flat. Maybe brass flanges to boot and bass that sounds like a washtub. False trebles are the least of anybody's problems.
Posted by: Nauvoo

Re: Pulsating, Wavering, Undulating Strings - 02/19/05 07:58 PM

Excellent counsel! Very good! Itís always smart to weigh the cost and effort versus the value of what you have in the first place. Balance! Sometimes the smart play is to simply walk away from it.
Posted by: BDB

Re: Pulsating, Wavering, Undulating Strings - 02/19/05 10:10 PM

I think Rod is trying to learn how to service pianos. In that case, restringing his piano is a good way to learn a lot of techniques which he will need. It's better for him to learn on his piano than to inflict himself on someone else's with no experience at all. As a matter of fact, it would be worthwhile for him to do as much work as he can, as carefully as he can, on three or four pianos. Otherwise, sending him out to work on other people's pianos would be as bad as sending students to a teacher who had never learned to play anything more than Chopsticks.
Posted by: Sam Casey

Re: Pulsating, Wavering, Undulating Strings - 02/20/05 09:10 AM

Semipro

I agree completely. I assumed the piano in question was a customers in which case the bigger picture should be considered.

What would be good too, along with working on the clunkers at home is to work with a dealer where there are lots of different pianos in various states. There you can get a feel of the business end as well as technical.