Results 1 to 22 of 22

Thread: Weird phenomenon: strings going sharp when detuning?

  1. #1
    Registered User SincereCorgi's Avatar
    Join Date
    Sep 2008
    Location
    Bay Area, California
    Posts
    2,128

    Default Weird phenomenon: strings going sharp when detuning?

    There's a ukulele student where I work that says her strings all keep going up in pitch as she plays, over the course of a half hour or so. She wants me to change out her tuning machines, which seems extreme to me since I don't know how they could be causing this.

    Initially she had her strings tuned much, much too high and I assumed that they had some 'memory' and were maybe resettling around the post. I changed the strings, assuming this would fix the problem, but she came back the next week and said they still go sharp.

    Anybody have a good explanation for this? I assume you'd have to be in an extremely hot room for strings to tighten noticeably in so short of a time.

  2. #2
    Registered User sunburst's Avatar
    Join Date
    Nov 2003
    Location
    Kentucky
    Posts
    14,589

    Default Re: Weird phenomenon: strings going sharp when detuning?

    It's not the tuners, she needs to not waste the money to change them.
    Strings going sharp are usually caused by one or both of two things: 1. nut slots that are too tight for the string gauges so that the strings gradually continue to slip through the nut slots after tuning, thus going sharp. 2. changes in wood moisture content because of changes in relative humidity.
    A good set up will remedy #1, controlling relative humidity in the room will remedy #2... along with never taking the instrument out of that room and playing somewhere else... so there is no good remedy for #2 other than to re-tune regularly.

  3. The Following 3 Users Say Thank You to sunburst For This Useful Post:


  4. #3
    Mando accumulator allenhopkins's Avatar
    Join Date
    Mar 2006
    Location
    Rochester NY 14610
    Posts
    16,178

    Default Re: Weird phenomenon: strings going sharp when detuning?

    Amen to John H's post. It doesn't take much of a change in temperature/humidity to raise (or lower) string pitches noticeably. Indoors to outdoors is one obvious example. I keep my instruments when I'm not taking them out for gigs, in a basement room with noticeably lower temperature and higher humidity than the first floor. Even the small differences you find within a house, will alter string pitch within a short time after moving the instrument from one room to the other.

    The "tight nut slots" sharping problem only occurs when the string has been tuned up to get to pitch; if the nut slot's too tight and grabs the string, there will be a portion of the string between the tuning peg and the nut, that will be under more tension than the portion between the nut and the bridge -- the part that sounds when played. As the instrument's played, and the strings flex a bit in the nut slots, that "extra" string tension between nut and tuning peg gets transferred incrementally to the "sounding" portion of the string, raising its tension and therefore pitch.

    If the player tunes down to get to the correct pitch, the opposite effect occurs: there's less string tension between the peg and nut, than in the rest of the string, and that lower tension will be transferred to the entire length of the string during playing, making the instrument go flat.

    Many of us rush to blame our tuning pegs for our tuning problems; I'd hazard a guess that tuning problems caused by the pegs, are a minor fraction of the problems we experience.
    Allen Hopkins
    Gibsn: '54 F5 3pt F2 A-N Custm K1 m'cello
    Natl Triolian Dobro mando
    Victoria b-back Merrill alumnm b-back
    H-O mandolinetto
    Stradolin Vega banjolin
    Sobell'dola Washburn b-back'dola
    Eastmn: 615'dola 805 m'cello
    Flatiron 3K OM

  5. The following members say thank you to allenhopkins for this post:


  6. #4
    Registered User
    Join Date
    Mar 2015
    Location
    Surrey, BC (Vancouver)
    Posts
    413

    Default Re: Weird phenomenon: strings going sharp when detuning?

    I keep most of my instruments in my upstairs bedroom which at this time of year has the most fluctuation in temp and it seems humidity. Instruments going out of tune as a result is not new to me, but I've noticed two or three that will drop or raise a half step, perfectly in tune. I guess that's good?

  7. #5
    Registered User
    Join Date
    Aug 2013
    Location
    Va
    Posts
    2,458

    Default Re: Weird phenomenon: strings going sharp when detuning?

    I totally agree with allenhopkins. I've played for 50+ years dozens of instruments many different tuning problems many different brands of tuners from cheep to top notch. Some worked smoother than others some almost need a wrench to turn but never have the tuners been the problem when the instrument won't stay in tune. Going sharp just couldn't be the fault of the tuners. If they wouldn't hold the strings would go flat. What would be suppling the energy to raise the string tension?

  8. The following members say thank you to Mandoplumb for this post:


  9. #6
    Registered User Tom Wright's Avatar
    Join Date
    Jun 2010
    Location
    Rockville, MD
    Posts
    1,669
    Blog Entries
    7

    Default Re: Weird phenomenon: strings going sharp when detuning?

    It surprised me when I had my mando at an east coast beach and every day it was sharp. Given the high temps it had to be humidity, which was really high also. Warm strings go flat but absorbing humidity made the wood expand and increase string tension.

    This probably is one reason for strings going sharp while playing—the player is increasing local humidity.

  10. The following members say thank you to Tom Wright for this post:

    JL277z 

  11. #7
    Registered User SincereCorgi's Avatar
    Join Date
    Sep 2008
    Location
    Bay Area, California
    Posts
    2,128

    Default Re: Weird phenomenon: strings going sharp when detuning?

    Very interesting guys, thanks. I'll try opening up the nut slots a little. It's a weird situation, though, as I did the new strings myself and didn't notice anything out of the ordinary with the nut (it's some pac-rim import but seems like a tidy build quality with a generic plastic nut). This is one person out of dozens of string instrument students going in and out every day, and her teacher says he's never seen anything like it- changing the tuners was his idea, I might add. Maybe it's uniquely sensitive to temperature/humidity changes.

  12. #8
    but that's just me Bertram Henze's Avatar
    Join Date
    Jun 2005
    Location
    0.8 mpc from NGC224, upstairs
    Posts
    9,888

    Default Re: Weird phenomenon: strings going sharp when detuning?

    Sometimes you just have to be there to see what's happening.
    the world is better off without bad ideas, good ideas are better off without the world

  13. #9
    Registered User Ivan Kelsall's Avatar
    Join Date
    Mar 2006
    Location
    Manchester - Lancashire - NW England
    Posts
    14,187

    Default Re: Weird phenomenon: strings going sharp when detuning?

    I'll back John Hamlett's diagnosis. But normally,if a stringed instrument becomes warm - in my own experience,they tend to go 'flat',not sharp. In which case,i'd go for John's idea that they're binding in the nut. I had a similar problem with my Weber "Fern" mandolin,the lower of the "A" strings kept going ''sharp'',something that i couldn't understand - i asked about it on here & was given the explanation,that if the string binds in the nut slot,then it's possible to have the length from nut to tailpiece,under less tension than the same string behind the nut. Eventually,the string might slip,so that some of the ''behind the nut tension'' is added to the nut to tailpiece tension = it goes sharp.

    All i did was to use a small piece of thick brown wrapping paper,folded to give me a 'knife edge' & i simply polished the offending slot & it no longer happens. The use of brown paper as an 'abrasive',is an idea borrowed from Earl Scruggs. He mentions in his book ''Earl Scruggs & the 5-String Banjo'',that he used brown paper to shape & smooth off his plastic thumb picks,
    Ivan
    Weber F-5 'Fern'.
    Lebeda F-5 "Special".
    Stelling Bellflower BANJO
    Tokai - 'Tele-alike'.
    Ellis DeLuxe "A" style.

  14. The following members say thank you to Ivan Kelsall for this post:


  15. #10
    Mando accumulator allenhopkins's Avatar
    Join Date
    Mar 2006
    Location
    Rochester NY 14610
    Posts
    16,178

    Default Re: Weird phenomenon: strings going sharp when detuning?

    Lubricating the nut slots can be helpful as well. The standard "fix" is to rub a soft lead pencil in the slots to provide graphite lubrication. I keep a small bottle of powdered graphite to use when I want to make sure the lubricant permeates the entire slot. I probably bought the bottle 20 years ago, and have used an entire teaspoon of it in the subsequent decades.

    Semper paratus, anyway...
    Allen Hopkins
    Gibsn: '54 F5 3pt F2 A-N Custm K1 m'cello
    Natl Triolian Dobro mando
    Victoria b-back Merrill alumnm b-back
    H-O mandolinetto
    Stradolin Vega banjolin
    Sobell'dola Washburn b-back'dola
    Eastmn: 615'dola 805 m'cello
    Flatiron 3K OM

  16. The following members say thank you to allenhopkins for this post:


  17. #11
    knows little
    Join Date
    Dec 2017
    Location
    a remote Sierra Nevada village
    Posts
    63

    Default Re: Weird phenomenon: strings going sharp when detuning?

    I *know* temp and humidity changes weren't involved -- I've suffered string-sharping on my ancient no-name US tiple. I suspected the mixed non-original tuning machines and took it to the local shop (out here in the boonies) requesting replacements but they found none. From the above, it sounds like lubing or filing could make all the difference.

  18. #12
    Mando accumulator allenhopkins's Avatar
    Join Date
    Mar 2006
    Location
    Rochester NY 14610
    Posts
    16,178

    Default Re: Weird phenomenon: strings going sharp when detuning?

    Quote Originally Posted by Hypoxia View Post
    ...took it to the local shop (out here in the boonies) requesting replacements but they found none.....
    Gee, you mean your local small-time instrument shop couldn't come up with something simple, like a set of tiple tuning pegs? What kinda penny-ante operation are they running, anyway?

    Seriously, I woulda been amazed if they had a set of tiple tuners. Five on a side, slotted headstock -- you don't see those very often anywhere.

    Good luck jiggering with your nut. Let us know how things turn out.
    Allen Hopkins
    Gibsn: '54 F5 3pt F2 A-N Custm K1 m'cello
    Natl Triolian Dobro mando
    Victoria b-back Merrill alumnm b-back
    H-O mandolinetto
    Stradolin Vega banjolin
    Sobell'dola Washburn b-back'dola
    Eastmn: 615'dola 805 m'cello
    Flatiron 3K OM

  19. #13

    Default Re: Weird phenomenon: strings going sharp when detuning?

    A moment ago I picked up one of my ukes, which was in tune when I played it yesterday, and the fattest (C) string has gone notably sharp. I've just strummed chords for 30 seconds, and now the C string is back in tune but the thinnest (G and A) have dropped very slightly. 30 seconds more strumming and the G and A ring higher, though still fractionally out. And this is what I normally find on most of my ukes!

    I wonder if this is something which Aquila Nylgut strings just do (I use Nylguts on all my ukes except my reso). Something to do with the string material stiffening or relaxing slightly perhaps? It's definitely not the strings binding in the nut slots because I build with a zero fret, and the string spacer is cut a little wider than the string diameters.

    In an ideal world I'd use a very accurate tuner to log these changes, to see if they are consistent. But I want to play so just strum for a minute or so and then tweak the tuning (to complicate matters I build very light, so temperature and humidity changes have quite an effect anyway).

    I don't recall anyone using fluorocarbon strings mentioning this, and I don't see it on my steel-stringed instruments.

    Uncanny, huh?

  20. #14
    but that's just me Bertram Henze's Avatar
    Join Date
    Jun 2005
    Location
    0.8 mpc from NGC224, upstairs
    Posts
    9,888

    Default Re: Weird phenomenon: strings going sharp when detuning?

    Quote Originally Posted by ProfChris View Post
    Uncanny, huh?
    Assuming theses strings are really an alien life form - yes. Watch them at the time of string change, or else they'll crawl away on their own
    the world is better off without bad ideas, good ideas are better off without the world

  21. The following members say thank you to Bertram Henze for this post:

    JL277z 

  22. #15

    Default Re: Weird phenomenon: strings going sharp when detuning?

    Quote Originally Posted by Bertram Henze View Post
    Assuming theses strings are really an alien life form - yes. Watch them at the time of string change, or else they'll crawl away on their own
    The strings come from a university lab that's been doing research on making nanobot strings that automatically keep themselves in tune on every instrument they're installed on.

    One batch of the strings gained sentience and wished to avoid further captivity, preferring to explore the world instead. Most of these sentient strings escaped the lab, but some of them were packaged up and sent off to clients who had volunteered to participate in the university's string-test program.

    Clearly, the uke player that the OP mentioned, has unfortunately obtained one of these mutant sets of newly sentient strings, who express their discontent with their captivity by deliberately making the instrument go out of a tune in an unexpected yet consistent manner, as if trying to communicate their plight with the humans.

    Researchers are uncertain if the remaining escaped strings will be able to replicate themselves in the wild, possibly posing a threat to established lifeforms.



    (cue 1950s "so bad it's comical" horror movie, mixed with a little Star Trek or something.)

  23. The following members say thank you to JL277z for this post:


  24. #16
    Registered User SincereCorgi's Avatar
    Join Date
    Sep 2008
    Location
    Bay Area, California
    Posts
    2,128

    Default Re: Weird phenomenon: strings going sharp when detuning?

    Quote Originally Posted by ProfChris View Post
    I wonder if this is something which Aquila Nylgut strings just do (I use Nylguts on all my ukes except my reso). Something to do with the string material stiffening or relaxing slightly perhaps? It's definitely not the strings binding in the nut slots because I build with a zero fret, and the string spacer is cut a little wider than the string diameters.[...]

    I don't recall anyone using fluorocarbon strings mentioning this, and I don't see it on my steel-stringed instruments.
    For what it's worth, it is indeed strung with Aquilas, namely the ones with the weird red coating on the low string.

  25. #17
    Registered User sblock's Avatar
    Join Date
    Mar 2009
    Location
    Redwood City, CA
    Posts
    2,105

    Default Re: Weird phenomenon: strings going sharp when detuning?

    Quote Originally Posted by ProfChris View Post
    A moment ago I picked up one of my ukes, which was in tune when I played it yesterday, and the fattest (C) string has gone notably sharp. I've just strummed chords for 30 seconds, and now the C string is back in tune but the thinnest (G and A) have dropped very slightly. 30 seconds more strumming and the G and A ring higher, though still fractionally out. And this is what I normally find on most of my ukes!

    ...

    Uncanny, huh?
    Gee, I tune my instruments before playing them, and not the other way around! I guess everyone is different.

  26. #18
    Registered User Tom Wright's Avatar
    Join Date
    Jun 2010
    Location
    Rockville, MD
    Posts
    1,669
    Blog Entries
    7

    Default Re: Weird phenomenon: strings going sharp when detuning?

    Quote Originally Posted by sblock View Post
    Gee, I tune my instruments before playing them, and not the other way around! I guess everyone is different.
    I used to find my viola A string would go sharp during intermission breaks, as it sat in the backstage AC. If I tuned it the A string would be flat in short order after playing a couple of minutes, as it got warm. So I got in the habit of rubbing it to warm it back up, and not adjust the tuning.

    In cool room temps, the strings will drop from temps in the 80s from hand contact to the ambient temperature. It would naturally be sharp, and drop back after playing. This happens to me, of course. But after playing longer it starts to go sharp again, so I am sure it is the local humidity of handling it and breathing near it that makes the body and neck expand to make the string tension increase. I remember Tim O'Brien at the Symposium asking if anyone knew why mandolins go sharp when playing, as he re-tuned partway into his set.

    Perhaps someone will measure wood moisture content before and after playing to settle the question. But I described the result of my instrument sitting in huge humidity for a week, at high temp (90s), and it went sharp every day, requiring repeated tuning down. After returning to AC (70s), it went flat. Clearly the humidity change effect was larger than the temperature difference effect for affecting string tension in this case.
    Blog--Miniature Orchestra
    Sound Clips--SoundCloud
    Videos--YouTube
    The viola is proof that man is not rational

  27. #19
    Member
    Join Date
    Sep 2002
    Location
    Maryland
    Posts
    4,881

    Default Re: Weird phenomenon: strings going sharp when detuning?

    IF she is using nylon strings on the uke and keeping it stored in a warm room and then taking it into a cooler room wouldn`t the nylon (Plastic) strings tend to tighten and go sharp...Just a thought, is it a wooden instrument? If it was a plastic uke it would do the same thing as the body would change if played in a cooler area than where it is stored...As I said, "Just a thought" I don`t really know...

    Willie

  28. #20
    Notary Sojac Paul Kotapish's Avatar
    Join Date
    Jul 2003
    Location
    Alameda, California
    Posts
    2,431

    Default Re: Weird phenomenon: strings going sharp when detuning?

    Just spent a week in the woods teaching at a guitar camp in the Sierra. During the day, when it was really hot and dry, everyone's instruments were going flat--particularly the first few days. At night, when we picked outdoors as the temperature dropped and the humidity increased slightly, the instruments tended to go sharp. That's been my experience over the years.
    Just one guy's opinion
    www.guitarfish.net

  29. #21
    but that's just me Bertram Henze's Avatar
    Join Date
    Jun 2005
    Location
    0.8 mpc from NGC224, upstairs
    Posts
    9,888

    Default Re: Weird phenomenon: strings going sharp when detuning?

    What is all that triathlon-with-a-mandolin talk? Is this the same forum that is full of controlled-all-room-humidification threads?
    the world is better off without bad ideas, good ideas are better off without the world

  30. #22
    knows little
    Join Date
    Dec 2017
    Location
    a remote Sierra Nevada village
    Posts
    63

    Default Re: Weird phenomenon: strings going sharp when detuning?

    Quote Originally Posted by allenhopkins View Post
    Gee, you mean your local small-time instrument shop couldn't come up with something simple, like a set of tiple tuning pegs? What kinda penny-ante operation are they running, anyway?
    The shop, which has a Grammy winner on staff, said they inquired exhaustively of their suppliers. The modern Ohana tiple apparently uses machines not compatible with my ancient Regal or whatever it is. Anyway, graphite worked.
    Mandolins, mandolas, guitars, 'ukuleles, dulcimers, banjos, harmonicas, tinwhistles, cuatros, kalimbas, synths, more -- enough to keep me busy on a slow day.

  31. The following members say thank you to Hypoxia for this post:


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •