MP
1150 posts
Dec 18, 2010
10:50 PM
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-well,
i've been hearing about removing tuning marks for sometime and had no idea why anyone would do this.
when i would ask, i'd get a rather vague answer like,"well, this improves the reeds," or similar.
anyway..i had this Bb that distorted on the 2 draw bend and i left it in a drawer forever.
today i took it out and the distortion didn't magically vanish- so i removed the covers, supported the 2 draw with a very thin shim, and with a sanding wand gently removed the chisel gouges at the rear of the reed. i sanded lengthwise.
i couldn't belive it! viola, the distortion was gone!
just tune it up to pitch and it's good to go.
anyway,i thought i'd share this experience.
any thoughts? did i correct it by removing the gouges; or did i inadvertently correct something else that was causing distortion?
cheers!
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MP
hibachi cook for the yakuza
doctor of semiotics
superhero emeritus
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jim
575 posts
Dec 18, 2010
11:24 PM
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Sounds like an off center reed
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www.truechromatic.com
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MP
1151 posts
Dec 18, 2010
11:38 PM
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--jim,i don't think so. i'm very good at centering reeds. but, the slots were full length embossed, so it's possible they were over-embossed.--------
MP
hibachi cook for the yakuza
doctor of semiotics
superhero emeritus
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jim
578 posts
Dec 18, 2010
11:42 PM
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Which is sort of the same thing in this context. ;)
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www.truechromatic.com
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MP
1153 posts
Dec 18, 2010
11:44 PM
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-i see. thanks.-they [the slots] appeared to be clear. i'll try this again on another offending harp. i think i have a MBD that distorts somewhere.--------
MP
hibachi cook for the yakuza
doctor of semiotics
superhero emeritus
Last Edited by on Dec 18, 2010 11:47 PM
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Rich
4 posts
Dec 19, 2010
2:28 AM
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MP.
I've gotta MBD Eb that has the same prob I think. The 2 draw bend squeaks and squeals like a stuck cat. The reed has a big arse tuning mark at the base. I think I'll give your fix a try. An inadvertant fix is still a fix!
Thanks mate
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MP
1155 posts
Dec 19, 2010
2:46 AM
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-no problem rich! jim knows quite a bit on this subject.---------
MP
hibachi cook for the yakuza
doctor of semiotics
superhero emeritus
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htownfess
227 posts
Dec 19, 2010
8:06 AM
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@MP: There's been a misconception that removing tuning marks reduces reed failures; reeds actually rarely fracture at a tuning gash, even heavy ones. People thought that sanding out the tuning marks would cure reed failure when actually it's sanding out the milling marks nearest the reed base that helps reduce failure on some (*not all*) types of reeds.
A phenomenon I ran into occasionally, especially with older Hohner reeds, was that a heavy enough tuning gash on a high reed would actually let the outer end of the reed flex independently of the rest of the reed, and the pitch would go *up* when played harder. That makes it impossible to tune octaves well, besides messing up the usual dynamics/intonation relation on that individual base note.
And that should give you a clue about your 2 draw reed: It probably was not misaligned, and probably was not embossed too close by usual standards, yet the wrong tuning gash might cause the reed to flex in less straight of a vertical plane than usual, with sideways excursions that contact the sides of the slot. So a reed that visually has normal clearance after embossing nonetheless makes noise. Sanding out the tuning mark may have taken out that inadvertent diagonal "hinge" effect.
One could argue that any embossed slot that buzzes is over-embossed, but sometimes there's something wrong with the reed itself, like misalignment, that makes it impossible to use your usual degree of embossing. In that case, you address the reed itself and then see whether there's still contact. The original problem really isn't the same as over-embossing a centered, well-aligned reed that's flexing in a normally straight plane.
When I say "usual degree of embossing," the riveted alignment of reeds has gotten so much better on many reedplate lines in the past decade that getting a close embossed clearance is much easier than it was on 1990s and earlier reedplates--much less cleanup required, especially if you're not going for absolutely minimal clearance. My older (1980s-90s) 105 Auto-Valve I customized required me to remount nine out of forty reeds with screws/nuts just to fix the alignment well enough to emboss them at all. Arrrrrgh!
@Rich and @MP: 2 draw on recent (post-2005) Hohner reeds has been problematic, with a 2 draw bend squeal on some but not all of them. An allusion to the problem can be found in http://www.modernbluesharmonica.com/board/board_topic/5560960/569408.htm , namely in urging people to complain to Hohner. If sanding out a tuning gash fixes it for you, that's great, but don't count on it. Hohner *seems* to have addressed this problem in the most recent production, probably by adjusting the milled profile that was the likely cause. Don't assume that Hohner wouldn't tweak some individual milling profiles if they get the kind of complaints they did on that one (i.e., both customizers and average customers), without changing all the other reeds.
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htownfess
228 posts
Dec 19, 2010
8:32 AM
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@Rich: Using the forum search engine again :), I find you brought this problem up about two weeks ago, and I haven't added much to what was said then; but try the sanding and see whether that fixes it. The last resort is replacing the reed outright, say with an older-generation one, which are readily available since 2 draw reeds don't die so often.
The 2 draw bend squeal problem seems to happen when the reed is bent past the normal intonation(s) of the full-step bend, making it really difficult for people learning to bend that hole, and also tough to use the BW-style "growl" sound that can come from bending that hole to its limit.
Another allusion to this problem & possible resolution can be found at the following place, but please don't drag harpwrench back into this discussion as he's got things to do: http://groups.google.com/group/harp-l/browse_thread/thread/708451bcdb0091c8/e5b715e0644ec23b?lnk=gst&q=2+draw+Joe+Spiers#e5b715e0644ec23b
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MP
1156 posts
Dec 19, 2010
10:35 AM
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-htownfess! howzit!
i remember some post or posts about defective hohner reeds and h********h saying complain to hohner.
my gouge was from a lee oskar chisel. i use it for cleaning in between bathroom tiles nowadays. said harp was an early victim of my ignorance and zeal.
i think on my MBD hiding somewhere that it's very probable it's got a defective reed and needs-surgery.--
RE- your autovalve; you are a patient man.------
MP
hibachi cook for the yakuza
doctor of semiotics
superhero emeritus
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jim
581 posts
Dec 19, 2010
12:23 PM
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take a closeer look at the reed. It may be propeller-twisted.
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www.truechromatic.com
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MP
1158 posts
Dec 19, 2010
1:05 PM
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another possiblilty. ----------
MP
hibachi cook for the yakuza
doctor of semiotics
superhero emeritus
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Rich
6 posts
Dec 19, 2010
3:11 PM
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Thanks for the advice Guys. Would 800 grit paper be the right kind of stuff to use?
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jim
584 posts
Dec 19, 2010
3:13 PM
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sure why not
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www.truechromatic.com
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