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Yamaha GH1 Woody Treble

  • 1.  Yamaha GH1 Woody Treble

    Posted 10-26-2014 22:03
    This message has been cross posted to the following Discussions: CAUT and Pianotech .
    I am looking for suggestions on how to reduce or eliminate a rather annoying woody knock when playing octaves 6 and 7 on a GH1 that is in an auditorium. The natural acoustics in the auditorium are great except they seem to amplify the sound to the point it was making me go insane during a pitch raise and tuning. The piano was a donation and  had very low use so the hammers are not flat or grooved. . Of course they are as hard as rocks so some needling would help but I do not want to kill the ability of the piano to be heard when the place is filled with people (200 +). The piano is sitting at floor level in front of the stage, ceiling are very high and there is a generous amount of  glass windows. I am trying to convince the management to get the piano on a truck and have it up on the stage where I think it will sound very different. I am scheduled to do some action regulation in about a week so I have some time to hear various ideas. Maybe I will find some things with the action out and it will play quieter after screws are tightened, bedding is checked, blow and let off are regulated.

    James Kelly
    Pawleys Island SC

  • 2.  RE: Yamaha GH1 Woody Treble

    Posted 10-26-2014 22:27

    Sometimes the wood sound is that the wip felts are too hard.  So "voice" the wippen cushions.  Take your voicing tool and push it sideways into the wippen cushion felt, to "fluff" it up. It will require doing some regulating. Also, make sure the keybed is bedded.

    Willem "Wim" Blees, RPT
    Mililani, HI 96789

  • 3.  RE: Yamaha GH1 Woody Treble

    Posted 10-27-2014 08:08
    Excellent suggestions and I was thinking about Keyframe bedding. Because of the metal/aluminum rails noises get amplified and passed from one part to another. I found this the case in another piano that was ironically in the same auditorium on loan. The hardened felt on the jack buttons made a thump that I traced down through the whippen to the flange rail.By needling the felt I tamed the beast. At first I tried a little fabric softener and that worked ...for five minutes. The piano sure smelled good. I bet the felts are contributing to the noise.... ------------------------------------------- James Kelly Pawleys Island SC 843-325-4357 -------------------------------------------

  • 4.  RE:Yamaha GH1 Woody Treble

    Posted 10-27-2014 08:42
    I'm not sure what is going on here. Is it woody sound on playing or release. I don't know why hard wippen rest felt or hard jack buttons would make a sound on playing?

    Larry Messerly, RPT
    Bringing Harmony to Homes

  • 5.  RE: Yamaha GH1 Woody Treble

    Posted 10-27-2014 09:13
    I would consider checking the bedding of  both front rail and balance rail. It's usually the front rail that would knock when the key is played aggressively. Knocking along the rail with your finger or a dowel that has a felt punching on the end (with the cheek blocks screwed down) will usually identify where the problem is and then sand with a very fine grit (600 at least) the part of the rail that does not knock near the offending knock. Good luck.

    Andrew Saderman
    Forest Hills NY

  • 6.  RE: Yamaha GH1 Woody Treble

    Posted 10-27-2014 11:37

    I will assume that the noise is when the note is played, not released.  The other noises can be bothersome, but I will focus on the impact noise that creates a 'woody' tone.  I like to make checklists, so here are some thoughts:


    - Strike point – adjust action in and out to see if it can be improved.

    - Keyframe bedding (front and balance rails)

    - Less than optimum hammer felt and molding – this is a kind of low cost instrument, after all

    - Excess hammer weight – heavy hammer molding. Trim front to back and on sides for lower weight.

    - Too much Shank flex at the thin area close to the hammer head. This accentuates the "knock" noise – but lowering the mass of the hammer head will also improve this, so try that first.  Carefully soaking the shank just in this area with water thin super glue can also stiffen the wood and reduce this noise.

    - Key balance holes too loose (this is worse on key release, but also can affect the impact sound a little)

    - Backchecks noisy (tends to make more 'clicky' or 'chuff' type sounds, though)


    There can be a matching of the hammer mass and the shank that causes strong front to back vibration of the hammer head after impact.  In slow motion films I have checked the rate of this vibration, and it can be right in the 120hz – 150hz range, which comes through as a knock. If the hammer is heavy, it well be lower in pitch, so lightening the hammer or stiffening the shank will raise the pitch out of the knocky sounding area. 


    Lowering the mass of the hammer is best because it allows the natural dampening factor of the shank material to stop the vibration faster and thereby reduce the noise.  Stiffening the shank will raise the pitch, but can also reduce the damping effect.  I guess this would depend on the properties of the glue, though.


    How much we hear it depends on the rest of the action and how it carries this knock sound to the keybed. I doubt that the action rail is contributing – if the rail itself were making noise, it would be high pitch, more of a 'clank' sound.  But I think it is good marketing of the wood rail proponents that blame aluminum rails for noise – they are too sandwiched with other materials (generally wood flanges on top and letoff rail below) to actually resonate or carry sound well.


    Finally, this can simply be a factor of the soundboard scaling and string scaling and belly rail materials.  If you knock on the bridge top and get a similar woody tone to the playing sound (take off a treble hammer and shank and knock the bridge with it), it might just be the way this piano is!


    Don Mannino


  • 7.  RE: Yamaha GH1 Woody Treble

    Posted 10-27-2014 14:40
    Wow... some great responses especially from Don. In one sense the piano is what it is. Certainly some of these suggestions will tame a little of the the beast but I do not have a big budget to blow. I will do what I can and address the bedding and a few other things. I like the idea of soaking some of the shanks with CA to stiffen them and may try it randomly.  I got some good responses on the Pianotech forum as well.

    James Kelly
    Pawleys Island SC

  • 8.  RE: Yamaha GH1 Woody Treble

    Posted 10-28-2014 10:47
    I guess my own question would be whether this is "normal" or "abnormal" woody sound. I know that when I have tuned within a very resonant, reverberant room (gym in particular), the woody attack component overpowers the pitch of the string, to the extent that it is hard to hear pitch. Usually, at the same time, the pitch lingers as well, so that it is doubly hard to tune because you are listening to time lapse: the past is still with you, and you don't hear where you have gotten to until it is too late.

    There are a lot of components. Obviously bad keyframe bedding can add an additional knock, but even if it isn't there, there will be keybed knock as the key bottoms out. That noise does enter the soundboard as well (as noted in the Giorgiano article on longitudinal waves, cited in that lengthy Pianotek thread). That is, the bridge moves in part at a frequency probably produced by keybed knock. There is also the hammer knock. It is a good idea to isolate the woody sound by playing the note hard while muting the string. That will tell you a lot about what the space is doing to amplify that sound (mostly by reverberation - it doesn't really amplify it, but the sound doesn't decay like it should in a good acoustical situation).

    If you want to see whether it is a matter of hammer mass, you can move a light hammer from, say, note 80 to note 65, and listen to the difference (obviously string grooves need to be addressed to make this a good test). For keybed noise, you can change out a couple front rail punchings for new and different styles. 

    Fred Sturm
    University of New Mexico
    "When I smell a flower, I don't think about how it was cultivated. I like to listen to music the same way." -Federico Mompou

  • 9.  RE: Yamaha GH1 Woody Treble

    Posted 10-28-2014 13:43

    Great comment!
    I have tuned in an auditorium where there was a double reverberation because of a very steep and deep balcony.
    The solutions were to turn the piano 90 degrees so the sound projected into the wing or when possible, to close the fire curtains.
    Similar things can happen when there is a plate glass window in a large room.

    Ed Sutton

  • 10.  RE: Yamaha GH1 Woody Treble

    Posted 10-28-2014 14:16
    One of my churches built a new building some years back. The sanctuary
    was poured concrete, bare walls, and octagonal in shape. Four pairs of
    hard parallel reflecting surfaces at 45?? angles to one another. C-8 on
    the piano produced 1-1/2 seconds of tone and another 3-4 seconds of
    echos. I've never seen anything like it. The sound (anywhere in the
    scale) immediately swelled and blended as echos overlapped and after a
    second or so it sounded like a psychotic toy organ instead of a Yamaha
    C-6. The echos continued long after the dampers had stopped the strings.
    A hand clap quickly blended into an extended tone as echos mixed, and I
    wish I'd have gotten to hear what it did to the choir, but never got the
    chance. Unfortunately, I did get to hear what it did to the tuning
    process for a couple of years while they attempted to work something out
    with the "architect". Wow! Vast amounts of additional money and a whole
    lot of acoustical panels later, and it became tolerable, though still
    lively. Woody knocks never had a chance.
    Ron N

  • 11.  RE: Yamaha GH1 Woody Treble

    Posted 10-28-2014 16:32
    Interesting, because of cross posting two different discussions taking place on this thread, one in Pianotech and one in Caut.  Mostly information that is being duplicated.  

    David Love RPT
    415 407 8320

  • 12.  RE: Yamaha GH1 Woody Treble

    Posted 06-13-2018 21:10
    I had this question just today, but a Seiler grand.  As you go up the scale, at about the time the dampers end, a "woody clack" starts and gets worse up to C8.  I get the same sound if I slide the action out and play the key with the hammer hitting my screwdriver instead of the string.  It's a slightly resonant "clack".  The hammers are fairly rounded and fat, so I thought there was too much hammer weight in proportion to the length of the string the hammer is activating.  I slightly sanded C8 and B7 shallow grooves, and it helped only slightly. I wondered if the hammers were reshaped, removing some shoulder felt and making the the striking point smaller, it might help.  I did test the strike point sliding the keyframe in and out.  I got a good sound but the "woody clack" was still there.

    Another thought was too much downbearing, so the string isn't resonant. Or a stiff soundboard.

    I have heard this sound in other pianos before.  It's just no one ever noticed so I didn't want to open a can of worms.  But she says now that the piano is tuned she can hear it.  The tuning was dreadful before so it masked over the noise.  I said I'd go to the discussion group and ask around.

    Robert Callaghan
    Reno NV

  • 13.  RE: Yamaha GH1 Woody Treble

    Posted 06-13-2018 21:14
    To me it sounds like you are describing loose hammers. Did you check the glue joints?

  • 14.  RE: Yamaha GH1 Woody Treble

    Posted 06-13-2018 21:33


                    As Mr. James Kelley mentioned; have the action screws (hammer flanges / wippens) been snugged up? Screws holding action rails to brackets, too? Brackets to keyframe? You probably already did that, but it was not said initially, so just double-checking. How hard are the hammers? Chris' thought of loose ones is a possibility, though I've heard it more as a "click" than a "clack". Everyone hears a little differently.

    Hey, good luck!

    Alan Hoeckelman, RPT

    SCC Music Tech



  • 15.  RE: Yamaha GH1 Woody Treble

    Posted 06-14-2018 11:03
    Gentlemen, assuming all glue joints, flanges, action screws are all checked/fixed, corrected-all the "normal" stuff-
    One real possibilty is to try a bit of what we now call "Spike & Peen" voicing. The technique was first "invented" by David Stanwood. Kent Swafford has also been a huge proponent of the techniqe. In fact in a recent post he took a picture of the 2 tools needed, & posted it on another forum (one in which there have been multiple discussions recently about it.)
    The "cliff notes" version is-first get the right size compass needle (readily available online) & chuck it up in a pin vise (Pianotek), then strick the surface of the hammer several times right into the crown. Step two, follow that with several strikes to the surface with a small ball pein hammer. David Stanwood was just saying he might to a short video on this & make available.
    Now this is not DEEP voicing at all! But it has (can have!!) an amazing effect on the tone quality & dynamic range while playing softly & medium but does NOT compromise the power, projection, etc with forte playing. Just a thought.

    [Kevin] [Fortenberry] [RPT]
    [Staff Techician]
    [Texas Tech Univ]
    [Lubbock] [TX]

  • 16.  RE: Yamaha GH1 Woody Treble

    Posted 06-16-2018 11:04
    Thanks for all your comments.?? It will be a while before I get back to
    this piano.?? But I do I now have a few ideas to try.


  • 17.  RE: Yamaha GH1 Woody Treble

    Posted 06-14-2018 13:48
    Re: Seiler

    While double checking the hammer glue joint and the other action screws are snug, make
    sure the hammer rest rail nuts are tight top and bottom.

    I realize the symptom you describe happens when you are just
    testing the blow, so it probably is not hammer rest rail being
    loose, but you might as well tighten them if they are.

    You can also move the action slightly forward (proximal) or back (distal) to check
    the strike point of the treble hammers. It may be there is
    a better position than you have at present. It may have moved
    from factory setting.

    Richard Adkins
    Piano Technician
    Coe College
    Cedar Rapids, IA