Welcome to the Piano World Piano Forums
Over 2 million posts about pianos, digital pianos, and all types of keyboard instruments
Join the World's Largest Community of Piano Lovers (it's free)
It's Fun to Play the Piano ... Please Pass It On!

Gifts and supplies for the musician
SEARCH
the Forums & Piano World

This custom search works much better than the built in one and allows searching older posts.
Ad (Piano Sing)
How to Make Your Piano Sing
(ad) Pearl River
Pearl River Pianos
(ad 125) Sweetwater - Digital Keyboards & Other Gear
Digital Pianos at Sweetwater
(ad) Pianoteq
(ad) P B Guide
Acoustic & Digital Piano Guide
Who's Online
123 registered (36251, accordeur, Adypiano, 34 invisible), 1519 Guests and 20 Spiders online.
Key: Admin, Global Mod, Mod
Quick Links to Useful Piano & Music Resources
Our Classified Ads
Find Piano Professionals-

*Piano Dealers - Piano Stores
*Piano Tuners
*Piano Teachers
*Piano Movers
*Piano Restorations
*Piano Manufacturers
*Organs

Quick Links:
*Advertise On Piano World
*Free Piano Newsletter
*Online Piano Recitals
*Piano Recitals Index
*Piano & Music Accessories
*Music School Listings
* Buying a Piano
*Buying A Acoustic Piano
*Buying a Digital Piano
*Pianos for Sale
*Sell Your Piano
*How Old is My Piano?
*Piano Books
*Piano Art, Pictures, & Posters
*Directory/Site Map
*Contest
*Links
*Virtual Piano
*Music Word Search
*Piano Screen Saver
*Piano Videos
*Virtual Piano Chords
Gift Ideas for Music Lovers!
Find the Perfect Gift for the Music Lovers on your List!
Visit our online store today.
Topic Options
#607281 - 02/02/09 10:39 PM Drifting String Frequencies
Jerry Viviano Offline
Full Member

Registered: 09/18/07
Posts: 263
Loc: Cary, NC
I've noticed with a both a needle-based Korg tuner, and with Tunelab97, that when a string is played on my piano, that the frequency which is read (be it the fundamental or some partial) drifts slightly through the sustain. From the beginning of the reading, to three or four seconds later, the frequency of most keys drifts up about 2 cents. This happens on many of the keys. Some are much more stable, and on a very few, they drift down. The up and down drifts can happen on neighboring keys. So it's not a case of the down-drifters are confined to one part of the scale and the up-drifters are at another.

The strings are in good visible shape, about twenty years old. No rust or any other form of apparent problems. But I've been noticing this for about as long as I remember. I always thought it was a problem with my Korg device. But I just started using Tunelab97 and it's showing the same thing. So I believe it's real. Is this a common trait of piano strings? Is it indicative of some known malady of the particular strings on my piano? Has anyone else observed this? I don't tune many other pianos, but I have seen it on others as well.
_________________________
Jerry Viviano
V. I. Piano
PTG Associate Member

Top
(ad PTG 757) The Value of PTG Membership
The Value of a PTG Membership
#607282 - 02/03/09 01:27 AM Re: Drifting String Frequencies
Keith Roberts Offline
1000 Post Club Member

Registered: 05/04/04
Posts: 1984
Loc: Murphys, Ca
Did you get the same result when you pluck the string. Use a guitar pick.

I liked your work but it looked as if the hammers were raked back way too much. Most grands only rake the hammers one or two degrees.
Was it the picture?
_________________________
Keith Roberts
Associate, PTG
Keith's Piano Service
Hathaway Pines,Ca

Top
#607283 - 02/03/09 03:13 AM Re: Drifting String Frequencies
Gregor Offline
Full Member

Registered: 10/31/08
Posts: 436
Loc: Münster, Germany
That´s normal. On every piano. Particularly in the bass. And there is a difference when you pound the key hard or soft. Pounded hard there is more deviation.

Gregor
_________________________
piano tech - tuner - dealer
Münster, Germany
www.weldert.de

Top
#607284 - 02/03/09 07:01 PM Re: Drifting String Frequencies
Jerry Viviano Offline
Full Member

Registered: 09/18/07
Posts: 263
Loc: Cary, NC
Keith,
I haven't tried plucking the strings. I will. But then Gregor say's the drift is normal. So maybe the drift is not really indicative of something wrong.

On the hammers being raked back - You're probably referring to the below picture:



Don't put any stock in that. It was just a spare shank and a spare hammer I had laying around that I threw together just for the photo not realizing the slant on the hammer. It was definitely bored incorrectly causing the apparent rake. That's why it was a leftover spare. I realized the rake in the photo after I had put all the equipment away and didn't want to go through the hassle of taking it all out and setting it up for the photo again. The hammers I actually installed in the piano were carefully checked to ensure that they were bored accurately and then installed at 90 degrees using Spurlock's grand hammer hanging jig. Let me know if there was some other reason you thought the hammers were raked back.
_________________________
Jerry Viviano
V. I. Piano
PTG Associate Member

Top
#607285 - 02/04/09 05:13 AM Re: Drifting String Frequencies
Gregor Offline
Full Member

Registered: 10/31/08
Posts: 436
Loc: Münster, Germany
I think a certain level of drift is normal and I think it has to do with the mass of the string. When you pound a thick bass string very hard, then it takes a little bit of time until the string "calms down".

But in some pianos there is a lot of drift even in the middle section or in higher notes and on some keys more than on the neighbouring keys. No idea about that. Perhaps string seating helps?

Gregor
_________________________
piano tech - tuner - dealer
Münster, Germany
www.weldert.de

Top
#607286 - 02/04/09 10:15 AM Re: Drifting String Frequencies
Keith Roberts Offline
1000 Post Club Member

Registered: 05/04/04
Posts: 1984
Loc: Murphys, Ca
Had me fooled.

If for some reason the hammer isn't rebounding nicely, it could inhibit the initial sound and there is a delay as the string energy comes into focus. Always determine if the problem is the string and terminations or the blow delivered to the strings.

Of course plucking the strings is the easiest and quickest way. Does anybody have any other tests?
_________________________
Keith Roberts
Associate, PTG
Keith's Piano Service
Hathaway Pines,Ca

Top
#607287 - 02/04/09 07:51 PM Re: Drifting String Frequencies
Jerry Viviano Offline
Full Member

Registered: 09/18/07
Posts: 263
Loc: Cary, NC
Keith,
Piano strings are fairly linear devices. Initial transient effects in linear systems tend to die out pretty quickly. As a pretty neat demo of this, here are some waveform images of some of the keys in the temperament of the same piano I captured with Reaper, which I described in my discussion of tuner training software. Note that these are recordings of true single piano strings, not simulated. The name of each track, at the very left of the track just above the volume adjustment sliders, are the names of the notes represented in each track.



The top of the image shows the time axis in seconds, so the whole graph is only about 2.4 seconds long. You can see that the transient effects vary from string to string, which I don't understand. May be poor rebound from the string on those notes, as you mentioned. But those effects, whatever they are, are only less than a tenth of a second. The worst shown here is on F4, the 6th trace from the top. You can also see from the traces that the higher strings decay at a much faster rate than the lower strings. Pretty dramatically so.

And just for ya-has, heres some of the waveforms zoomed way in, so that you can see the actual time representation of what the microphone picked up.



You can see from these that some of the keys have a lot more higher partial content than the others. Possibly because I've never voiced the hammers since I installed them. Some are significantly quieter than the other as well. I noticed this happening when I was recording them, although I couldn't detect much difference in volume through my ears. Don't know what to say about that.

The bottom set of notes are not all the same as the top set but most of them are. Of the ones that are common to both sets, you can see that the ones with the strongest transient effects in the top also appear to be the least well-behaved ones when you zoom way into them in the bottom set. Pretty cool, huh? I wonder if the ones with the stronger transient effects could be because of poor string terminations, or perhaps loose hammer flanges, or who knows what?

I'd say that there is probably a lot that could be learned by studying these things. I just started looking at them in the past week or so. It will be interesting finding where this brings me, if I stick with it.
_________________________
Jerry Viviano
V. I. Piano
PTG Associate Member

Top

Moderator:  Piano World 
What's Hot!!
HOW TO POST PICTURES on the Piano Forums
-------------------
Sharing is Caring!
About the Buttons
-------------------
Forums Rules & Help
-------------------
ADVERTISE
on Piano World

The world's most popular piano web site.
-------------------
PIANO BOOKS
Interesting books about the piano, pianists, piano history, biographies, memoirs and more!
(ad) Piano Music Sale - Dover Publications
Piano Music Sale
Ad (Seiler/Knabe)
Knabe Pianos
(ad) HAILUN Pianos
Hailun Pianos - Click for More
(125ad) Dampp Chaser
Dampp Chaser Piano Life Saver
(ad) Lindeblad Piano
Lindeblad Piano Restoration
(ad) Estonia Piano
Estonia Pianos
Sheet Music Plus (125)
Sheet Music Plus Featured Sale
New Topics - Multiple Forums
Advise and Feedback on Online Piano Lessons
by [w]
9 minutes 12 seconds ago
Anyone have a burglar step on his grand piano?
by swampwiz
23 minutes 17 seconds ago
Casio px-150
by Eddyaknow
Today at 05:50 PM
Advice for a returner
by tried42long
Today at 03:40 PM
Humidity and condensation
by Phil Greenough
Today at 03:37 PM
Forum Stats
76999 Members
42 Forums
159253 Topics
2339416 Posts

Max Online: 15252 @ 03/21/10 11:39 PM
(ads by Google)

Visit our online store for gifts for music lovers

 
Help keep the forums up and running with a donation, any amount is appreciated!
Or by becoming a Subscribing member! Thank-you.
Donate   Subscribe
 
Our Piano Related Classified Ads
|
Dealers | Tuners | Lessons | Movers | Restorations | Pianos For Sale | Sell Your Piano |

Advertise on Piano World
| Subscribe | Piano World | PianoSupplies.com | Advertise on Piano World | Donate | Link to Us | Classifieds |
| |Contact | Privacy | Legal | About Us | Site Map | Free Newsletter | Press Room |


copyright 1997 - 2014 Piano World ® all rights reserved
No part of this site may be reproduced without prior written permission