Dull notes from torqued reed bar?

[cinnanon]

I don't know if this has ever been mentioned before, but does anybody know the purpose of the paper shims under the reed bar? Is it to un-torque the reed bar or to torque it? I replaced a reed on a slightly dull note, #54. The note sounded fine before I brought it up to pitch, but when I brought it to pitch the note sounded like the old reed. Slightly duller than the rest. Has anyone experimented with the reed bar twist? Is it a resonant frequency thing? I'm pondering why these shims are there as I think it may be dampering some vibrations. If that were true, I guess I would get a loud note that tapers off quicker rather than a softer note. I'm trying to get the best sound out of this thing but i'm not sure why they did certain things. I could try it but wanted to ask if anyone had some insight into it.

Thanks

[pianotuner steveo]

What model are you talking about?



My guess s that they just shimmed to get the proper height (hammer stroke)make sure there s no it around the reed mounting hole. In most models except the earliest, there should be a concave washer under the reed bolt- the hump side goes UP. If that is missing, then that may have something to do with it.

[cinnanon]

200A. I do have some extra reed screws. I'm gonna try to replace one and see if it makes a difference.

[pianotuner steveo]

But do you have the washers?

[cinnanon]

Yes they aren't really removable.

[pianotuner steveo]

Hmmmm...not sure what you mean by they aren't removable...the ones that I have come right off of the bolts...

[Max Brink]

Going back to the original post:

I replaced a reed on a slightly dull note, #54. The note sounded fine before I brought it up to pitch, but when I brought it to pitch the note sounded like the old reed. Slightly duller than the rest. Has anyone experimented with the reed bar twist? Is it a resonant frequency thing? I'm pondering why these shims are there as I think it may be dampering some vibrations.

You're in one of my least favorite territories but it sounds like you're already on the right track with the shims. Different shim heights will affect the resonant frequency of the harp and it's never an exact measurable science. If you get to extreme with the shims you may negatively affect the strike line of the harp, however, and for that matter the dull note may be a strike line issue for that particular note.

[pianotuner steveo]

Right. You may need to soften the glue (with heat) for that one hammer and adjust the strike point. Most likely you would need to push the hammer tip slightly towards the back of the piano, but be sure you need to do this before actually doing it. A way to test would be loosen the reed bar screws, and pull the reed bar toward you near that note and see if the tone improves.

You also could have a bad hammer, but that is pretty rare in a wurli. If the felt were worn away, it would have a different tone issue.
Almost a metallic sound.


PLEASE NOTE: heating and moving a hammer forward or back is not a normal everyday thing to do. I've very rarely ever had to do this in 40 years.

[dvanbeever]

I just came across this post and this was exactly my problem!  I had recently cleaned the piano and taken it apart and then put it all back together and all of a sudden one of my notes was dull and flat sounding.  I lightly sanded it but no luck.  I ordered a new reed, put it in and it was just as dull and lifeless as the old one.  I started loosening the harp assembly and the note now sounded for longer and was as good as any other.  Planning on shimming the reed bar a little (I vaguely recall a piece of paper falling out when I was working on it) and hoping that it will allow me to tighten screws all the way.  Interestingly I used to play upright bass and a similar sort of resonant effect occurred on a bowed note.  I had to get a "wolf tone eliminator" to add mass to the string and keep the note from sounding dull and interfering with itself.

[DocWurly]

I am sure this is answered elsewhere, but purpose of shims is to untorque. You want it such that there is no rocking of the reed bars at all when corner screws are loose. Otherwise, when you tighten the screws, the reed bars will twist, and notes, especially near one end or the other, will have a deadened sustain. The difference of the degree of thinness of a single shim can make a dramatic difference.  Turns out to be very important.