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Damper Bleed

  • 1.  Damper Bleed

    Posted 09-19-2016 13:52

    Hi All

    I service a rather new Steinway D that is in a very "live" recital hall.  The tuner that regularly tunes the piano strips mutes just above (distal) the dampers.  I was called to address several notes the "kept on ringing" as well as sympathetic ringing when other notes were played.  What I found was multiple damper felts that were, so to speak, shredded.  This was apparent in the trichord felts of the wound and plain wire strings.  


    I replaced the offending as well as all the trichord felts with dampers from Steinway.  The felt appears to be seated properly and the damper is working efficiently.  When I press on the strings at the proximal and distal ends of the dampers the dampers follow the strings.  


    After I play a note and release the key, or play multiple notes with the dampers up and release the keys and release the damper pedal there still seems to be and ever present and lingering sympathetic vibration.  I have added finger weight as well as bean bag weight on top of the dampers and plucked the strings to check for damper seating and damping of the individual strings.  


    I am wondering if any of you have encountered this kind of "ghost" phenomenon.  I did try longer pieces of felt and harder Tokiwa felt as well as Laoureux Steinway style felt.


    Thanks for your opinions.  


    Henry Nicolaides

    Southern Illinois University at Carbondale, School of Music





  • 2.  RE: Damper Bleed

    Registered Piano Technician
    Posted 09-19-2016 13:57

    Hi Doc

    Could it be sympathetic vibrations from lower strings?  When you hear it put your hand on the bass strings and see if it disappears. The other tuner's fault of not raising the dampers when putting in their temperament strip probably did damage there too. 

    Hope me you are well!

    Chris

    ------------------------------
    Christopher Purdy, RPT
    Piano Technician
    Middle Tennessee State University
    Murfreesboro, Tennessee 37132
    (740) 590-3842



  • 3.  RE: Damper Bleed

    Posted 09-19-2016 14:32

    Not raising the dampers while installing a temperament will cause the strip to pinch the trichords and rip the tips when the key is played. You might need to install stringing braid between the tenor duplex and the bridge, these string segments can keep ringing.

    ------------------------------
    Regards,

    Jon Page



  • 4.  RE: Damper Bleed

    Posted 09-20-2016 04:04
    I have never ever used a strip of felt when setting the bearings. Only one rubber wedge - for the reason of potential damage to the damper felts.     Michael   UK





  • 5.  RE: Damper Bleed

    Registered Piano Technician
    Posted 09-20-2016 06:21

    Henry's question poses multiple, and somewhat unconnected issues.  One could reasonably conclude that the problem of damaged damper wedges was the result of the careless insertion of a strip mute, or perhaps the use of an overly thick one, but I wouldn't claim this as proof that strip muting cannot be done successfully, and safely.  The question of inadequate damping is less easily diagnosed, as is evident from the range of comments already provided.  As Ed pointed out, it's not clear that the 'bleed' is even coming directly from the piano, but, even if so, it's also not clear how much of the original damperwork remains, or whether the problem existed even prior to the damper damage.  

    Henry, you need to take the time to isolate the source and pitch.  Pressing down the string to check for damper-follow is not likely to tell you too much.  As Chris said, see if hand-damping of bass section has any effect.  See if there are any very active duplexes and mute them, temporarily.  Pluck individual strings of tricords to see if they are damping equally. 

    Is it subtle, or so obvious as to make the piano unusable?

    ------------------------------
    David Skolnik
    Hastings-on-Hudson NY
    914-231-7565



  • 6.  RE: Damper Bleed

    Posted 09-21-2016 10:46

    This is subtle.  I will visit the piano this Saturday and will check the welcomed suggestions.  I generally do not tune this piano, but for the record I have strip muted pianos for years without damage to dampers (except for the first one that I "forgot" to raise the dampers). I also use felt wedges and agree one has to be very cautious to avoid damper damage.  I'll post pics of some dampers and the telltale residual red felt on the soundboard later.

    Henry.  

    ------------------------------
    Henry Nicolaides
    Piano Technician
    Southern Illinois University
    Carbondale, Illinois
    email: henryn@siu.edu
    Phone: 618-967-3796



  • 7.  RE: Damper Bleed

    Posted 09-20-2016 14:12

    Ok Mike,

    So you never augmented tension or torque a ton pitch raising 100 cents? Pitch raises are optional.

    Only way I am going to stress the board that way is one string in one unison at a time. Given the risk, plate damage, belly damage, or damper felt damage, I will go with damper felts every time. 

    ------------------------------
    Benjamin Sloane
    Cincinnati OH
    513-257-8480



  • 8.  RE: Damper Bleed

    Posted 09-21-2016 12:35
    When tuning the Pit grand at Glyndebourne I frequently had to raise (or lower) the pitch to any one of the following: A = 440, A = 430,    A = 415. For this I used an ETD for the A's only and raced through a tuning sequence (of my devising) by ear to keep the frame stable. The sequence was something like this: Over-Tune all the 'A's (depending whether one is going up or down (rather like shares . . ) Over-tune all intermediate Maj.1/3rds. Then go on to all the G's - over-tuning them by a bit less than the G's followed by their intermediate Maj 1/3rds - &c. &c.
    This way I was able to completely retune to a new pitch within and hour-or-so (one gets faster with practice so allow 1.1/2 hrs to start with)     Michael   UK





  • 9.  RE: Damper Bleed

    Registered Piano Technician
    Posted 09-22-2016 13:35

    Several points:

    If the trichord (and bichord) felt is trimmed so it doesn't hang below the wire you don't have to worry about it too much.

    If you "set" the mute between the strings, rather than shove it down, you won't displace the wire. I use a single 3/4" rubber mute, on grands, wider ones won't tip over, no handle, you can set the mute between the strings without moving the wire at all.

    Uprights I use one split rubber mute (3/8") with handle. It takes very little pressure to keep it in place if the mute is newish. Placed near the string termination it will not displace the wire. In the low treble where the mute is placed nearer the dampers often they are flat dampers so no problem.

    Try a thinner mute strip if you are so inclined to use them (I don't). The ones sold are too thick. But I would still push down the pedal before inserting s mute strip as string displacement is more likely even with a thinner strip.

    ------------------------------
    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320



  • 10.  RE: Damper Bleed

    Registered Piano Technician
    Posted 09-23-2016 12:18

    Regarding the fact that the temperament strips are usually too thick:

    Although Schaff's 209T (T for thin) is pretty close on many pianos, and once they get really broken in/worn, they do get thinner. So I keep these for situations in which I need thin ones. 

    Also, Pianotek sells a much thinner one. (the ones I have are green and are 3mm. Their much thinker one is usually red and is 4mm.)  They are not tapered, so I taper them myself and really like them. You could have a few of these on hand with different tapers. 

    Also, I used to keep a fairly narrow strip of basic action cloth handy in case I needed something thinner. The last one I had was brown--I think it's called sticker cloth, intended for replacing the square action cloth on the bottom of upright abstracts/stickers.

    Just another nice option. I use single mutes above the dampers and many times in the bass--but I much prefer strip mutes in the mid-range. Much faster FOR ME at least. 

    ------------------------------
    [Kevin] [Fortenberry] [RPT]
    [Staff Techician]
    [Texas Tech Univ]
    [Lubbock] [TX]
    [8067783962]



  • 11.  RE: Damper Bleed

    Posted 09-23-2016 12:42
    I use action (sticker) cloth strips in the treble and bass. Tapered, two
    strips cut from one, in the treble, and full width in the bass. The best
    I've ever found for the center is a strip Pearl River passed out at a
    national one year. It's a thin action cloth sewn to a strip of Ecsaine.
    Just the right stiffness and thickness for most pianos. I carry a felt
    strip too for those pianos the Pearl River strip doesn't fit. Effective
    damping without excessive hassle getting the things in or out. I'm
    really surprised these Pearl River strips aren't offered for sale, as
    they're very good. Or maybe they are and I'm just ignorant of the fact.
    Old strips get cut up for temporary mutes with string replacements.
    Ron N




  • 12.  RE: Damper Bleed

    Posted 09-23-2016 19:29
    Edited by Benjamin Sloane 09-23-2016 19:48

    Trimming trichord wedges is common ersatz for easing into double block dampening combining blocks and trichord wedges for timing. This mistake appears constantly in restoration jobs and some unrestored pianos and cannot be remedied.

    Squeezing pliers confuse these questions with temporary fixes. 

    With new damper felt and wires it is absolutely essential that wires be bent free in the damper levers IMMEDIATELY. Some wires have no second chance after incompetent bending which promotes fear about bending. Problems are introduced that cannot be ameliorated bending damper wires wrong inspiring trepidation about wire bending from competent techs.

    ABSOLUTELY NO OVERTIGHTENING of damper lever screw. This is a wire that CANNOT be nicked though the nick will be hidden from plain view. Trimming trichord wedges and squeezing pliers must NEVER be used before damper wires are squarely in place. Not everyone is prepared to do this with wires.

    But frequently wedges are.

    ------------------------------
    Benjamin Sloane
    Cincinnati OH
    513-257-8480



  • 13.  RE: Damper Bleed

    Posted 09-19-2016 21:52

    I was called about a "stuck damper pedal" which turned out to be the reverb from a marble staircase.

    There can be reverb from the loft above the stage, very sensitive to location of the instrument.

    ------------------------------
    Ed Sutton
    ed440@me.com
    (980) 254-7413



  • 14.  RE: Damper Bleed

    Posted 09-19-2016 22:38

    What is upweight?

    ------------------------------
    Benjamin Sloane
    Cincinnati OH
    513-257-8480



  • 15.  RE: Damper Bleed

    Posted 09-20-2016 06:45
    Henry,
    How is the timing; it may be lifting very early which could indicate that the underlevers are slightly touching the ends of the key on the return.

    Sent from my iPad