asilve3
91 posts
Apr 19, 2010
8:12 AM
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Why is it that when I set up my harmonicas the notes play better when the cover plates are off? As soon as I put them on, the harp feels a lot different and doesn't play as well. Notes start getting stuck or hesitate. The harp I'm working on is a C Golden Melody. Whats up with that?
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http://www.youtube.com/user/asilve3
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Gwood420
132 posts
Apr 19, 2010
10:01 AM
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i have noticed that too.... started adjusting with them on....
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nacoran
1711 posts
Apr 19, 2010
10:29 AM
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I could come up with a total guess theory about air pressure but I'd rather wait to see if someone who knows better has something to say.
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Nate
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barbequebob
725 posts
Apr 19, 2010
12:17 PM
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All harps play at their loudest when the cover plates are removed and you just found out just how much the design of the cover plates have an enormous effect on the sound. The more open they are, the louder and brighter they play. With more enclosed covers, when the air hits the metal that's enclosing it, like the way the lip on the back covers of a Marine Band or Special 20 are, the air dies out and the volume drops. Unless requested to do otherwise, all customizers open the back covers of the harps and that alone increases the overall volume of the instrument alone.
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Sincerely,
Barbeque Bob Maglinte
Boston, MA
http://www.barbequebob.com
CD available at http://www.cdbaby.com/cd/bbmaglinte
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Gwood420
135 posts
Apr 19, 2010
12:27 PM
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bob, i think what he ment(cause i noticed this too) was that when you take the plates off, and gap the reads, while you test them with the coverplates off they always sound persfect IE: there is no hesitation, or even stuck reads.. but when you put them back on its another story..
for example, i gapped my 4 for overblowing, and with the plates off everything was awesome! but as soon as i put them back on, the ob was squeeky, and the transfer from draw to blow had a hesitation.. take em off to fix, and it seems back to great again.. or when you put em back on, one of the notes would stick, but take it off, it is all good..
thats why i started gapping with the plates on, seems i have less issue.. im would guess it is a pressure thing, or possably the ambisure(spelling)...
Last Edited by on Apr 19, 2010 12:28 PM
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barbequebob
727 posts
Apr 19, 2010
12:33 PM
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It then sounds like he called the reed plates the cover plates, which is NOT the same thing, obviously, and I went by his description of cover plates, which is obviously a different thing entirely.
The thing is when you remove the reed plates (which is the correct terminology here) is make sure that they are properly aligned and if they are not properly aligned together, you won''t get the proper results.
If you remove the reed plates, make sure you have them properly realigned and screwed back together, but also test it with the cover plates back on because you may cause some unwanted funky crap happening that is unwanted and unintended and this is something most customizers will tell you to do.
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Sincerely,
Barbeque Bob Maglinte
Boston, MA
http://www.barbequebob.com
CD available at http://www.cdbaby.com/cd/bbmaglinte
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asilve3
92 posts
Apr 19, 2010
12:37 PM
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that is exactly what I meant. I have noticed with the GMs when you cut holes in the sides of the cover plates just under the screws they immediately play better.
Is the solution to adjust my cover plates? Are my gaps too tight?
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http://www.youtube.com/user/asilve3
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asilve3
93 posts
Apr 19, 2010
12:41 PM
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@bob
I am not talking about the reed plates. I AM talking about cover plates. I am not referring to the volume of the harmonica but rather the difference in reed response with cover plates on vs. off.
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http://www.youtube.com/user/asilve3
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barbequebob
728 posts
Apr 19, 2010
2:43 PM
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It sounds more like an adjustment of the cover plates, largely the alignment more than anything else. I`m sure one of the BEST customizers in the business, Joe Spiers AKA harpwrench will chime in soon.
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Sincerely,
Barbeque Bob Maglinte
Boston, MA
http://www.barbequebob.com
CD available at http://www.cdbaby.com/cd/bbmaglinte
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phogi
401 posts
Apr 19, 2010
3:09 PM
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I if you are talking about setting up overblows and overdraws, I know one possible reason:
If your lips are touching the blowreed (for an ob)or the draw reed (for an OD), then there is no sympathetic vibration, and therefore no squeal.
Also, the screws holding on the coverplates could be bending the reed plate, causing leakage. Just a thought.
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HarveyHarp
7 posts
Apr 19, 2010
3:36 PM
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Your embrouchure is probably different with the cover plates on, and you are probably blowing harder. Maybe too hard.
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barbequebob
729 posts
Apr 19, 2010
4:21 PM
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The above two postings are important possibilities one definitely should consider. If the reed plates are getting warped in the process, it`s usually caused by severe overtightening of either the reed plate screws and/or the cover plate screws.
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Sincerely,
Barbeque Bob Maglinte
Boston, MA
http://www.barbequebob.com
CD available at http://www.cdbaby.com/cd/bbmaglinte
Last Edited by on Apr 19, 2010 4:27 PM
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528hemi
88 posts
Apr 19, 2010
4:28 PM
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The above is true and can bet that is the issue. What you want to do is just lay the covers back on and try them before screwign them, down and then you can tweak some more if they start to stick or sound airy.
"Your embrouchure is probably different with the cover plates on, and you are probably blowing harder. Maybe too hard"
528hemi
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harpwrench
235 posts
Apr 19, 2010
4:32 PM
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A little bit of air leaks between the comb and reed plates without the covers clamping them together at the mouthpiece. Installing the covers seals that leakage off and more airflow is directed past the reeds. If your reeds are set up super tight, opening the gaps slightly may help.
The same phenomenon occurs sometimes when you set up a Marine Band, then screw the reed plates as an afterthought. I personally like a nailed Marine Band better, and I'm not alone. They feel like they vibrate better, hard to describe. A whole boat-load of elite professional harps made over the last 15 years by the pioneers of diatonic customizing have retained the nails- probably no coincidence.
As an experiment, loosen the reed plate screws a little bit and then install the coverplates. If it plays perfectly, you could save yourself a lot of grief by putting a bit of nail polish on the loosened screws to keep them from backing off further, and just play it.
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asilve3
94 posts
Apr 20, 2010
4:02 AM
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Very interesting. Thanks for the info everyone. I will try this out and post my results.
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http://www.youtube.com/user/asilve3
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LIP RIPPER
211 posts
Apr 20, 2010
4:15 AM
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Joe, that is a very interesting comment about the nails. I am looking at a late 30's "D" harp on my desk that I've sanded, sealed , embossed etc. I haven't found any small screws to put it back together. I have just put the 4 coverplate nails in about half way.In this condition it plays really well and I've been tempted to just nail it back together. I think you just pushed me over the fence.
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LIP RIPPER
212 posts
Apr 20, 2010
4:17 AM
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Joe, that is a very interesting comment about the nails. I am looking at a late 30's "D" harp on my desk that I've sanded, sealed , embossed etc. I haven't found any small screws to put it back together. I have just put the 4 coverplate nails in about half way.In this condition it plays really well and I've been tempted to just nail it back together. I think you just pushed me over the fence.
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Baker
51 posts
Apr 20, 2010
4:54 AM
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My 0.02. I had the same problem. Are your replacing the nails with bolts? I found than when I was drilling out the holes for the cover plate bolts I was making the hole as small as possible so the cover plate bolts were really snug. I wanted as little room for them to move as possible. I also did them up fairly tightly.
What I discovered was that if I gave them a little more room to fit in the holes, enough so when you tip it upside down they will fall out on their own accord and just tighten them enough to bite a little it solved the problem.
I am guessing than the tension was acting on the reed plates and causing them to move.
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ElkRiverHarmonicas
382 posts
Apr 21, 2010
3:45 AM
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Does how it play change any when you loosen or tighten the coverplate screws?
BTW, people in the 1800s played a lot of harmonicas that had no coverplates, which were invented to keep German moustaches out of the reeds.
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www.harrisonharmonicas.com
www.elkriverharmonicas.com
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hvyj
289 posts
Apr 21, 2010
5:28 AM
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You know, I don't work on my harps except to gap them, but sometimes after I've gapped a harp and put the covers back on and screw them down nice and tight, the harp doesn't sound right. In that situation, loosening the coverplate screws slightly almost always solves the problem.
I have no idea why this is so, but I've always assumed that screwing the covers on too tight had some negative effect on the the reedplates. Maybe harpwrench or elkriver can enlighten us about this.
Last Edited by on Apr 21, 2010 5:28 AM
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asilve3
95 posts
Apr 21, 2010
5:41 PM
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I tried loosening up the reed plates and the cover plates. It seems to have made a difference. I think I am going to have to find the balance between the plates and gapping to get it right. Thank you to everyone for contributing.
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http://www.youtube.com/user/asilve3
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ElkRiverHarmonicas
383 posts
Apr 21, 2010
6:45 PM
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No, your issue is alignment. When you tighten screws and thereby change the curve of the reedplate itself, you actually slightly, very slightly, change the shape of the slot horizontally. If you have a burr, or a slightly misaligned reed, you can make the reed strike slot or burr after tightening or loosening screws. This mostly happens after overembossing.
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www.harrisonharmonicas.com
www.elkriverharmonicas.com
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asilve3
96 posts
Apr 21, 2010
9:07 PM
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@elkriver
I have been concerned about misaligned reeds for a while. How do you fix a misaligned reed? I know you need a reed wrench... Is there an equivalent available at my local hardware store? Once I have one, how do I align it properly?
Also, what are some tell tale signs of misaligned reeds?
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http://www.youtube.com/user/asilve3
Last Edited by on Apr 21, 2010 9:08 PM
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arzajac
161 posts
Apr 22, 2010
5:01 AM
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I'm a beginner.
I've been trying my hand at gapping for about six months. I've bought a few cheap harps on ebay to play around with.
I can confirm the effect Aslive3 mentions and, for me, it's not due to tight screws on the coverplates.
I can consistently (on three different harps) gap a hole and have it play beautifully - I can even bend up the overblow with the coverplates off. But when I simply place the coverplates on without screws, it all changes.
What's consistent is that it changes. *How* it changes is not consistent. Sometimes the blow reed will start to be sticky, sometimes the hole will seem leaky. Usually, it will take a lot more work (air/mouth position) to get the overblow to sound. Putting the screws on and tightening or leaving them loose does not change a thing. Taking them off again, I can go back to being able to hit the overblow effortlessly.
I chalked it up to inexperience and I'm sure that I just have to work on it. But knowing why this phenomenon happens would be nice. Is it because there is less distance between my lips and the reeds? Is the compressible volume smaller and therefore the hole is more precise?
Last Edited by on Apr 22, 2010 5:02 AM
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barbequebob
744 posts
Apr 22, 2010
9:44 AM
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Just a tiny bit of misalignment can make a big difference.
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Sincerely,
Barbeque Bob Maglinte
Boston, MA
http://www.barbequebob.com
CD available at http://www.cdbaby.com/cd/bbmaglinte
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arzajac
162 posts
Apr 22, 2010
1:50 PM
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It's definitely not alignment.
I can squeeze the hell out of the sides without the coverplates on and there is no change. The only thing that changes the way the hole plays is the presence of the coverplates.
Unless the presence of the coverplates somehow changes the alignment in another way... Any other ideas?
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ElkRiverHarmonicas
389 posts
Apr 22, 2010
2:48 PM
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Try the screws without the coverplates and see what happens.
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arzajac
163 posts
Apr 22, 2010
4:47 PM
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Already tried that.
This is something I have noticed since the first time I tried my hand at gapping. It must be something obvious to all you people with experience.
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ElkRiverHarmonicas
390 posts
Apr 22, 2010
5:03 PM
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Oh, I think I've got it now. Try squeezing the top.
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asilve3
97 posts
Apr 22, 2010
6:04 PM
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@elkriver
I have been concerned about misaligned reeds for a while. How do you fix a misaligned reed? I know you need a reed wrench... Is there an equivalent available at my local hardware store? Once I have one, how do I align it properly?
Also, what are some tell tale signs of misaligned reeds?
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http://www.youtube.com/user/asilve3
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MP
187 posts
Apr 22, 2010
7:28 PM
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HOHNER has a kit with a wrench for your GM. this wrench also works on SP20s MBs MBDs and crossovers. i make wrenches, but best you just get a hohner wrench.
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ElkRiverHarmonicas
393 posts
Apr 23, 2010
5:43 PM
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You can scootch it over with a .002 shim, sold as feeler gauges in auto parts store. I think your problem might be it's gapped too low, at least that's why I was asking about pinching the top. You gap too tight and it plays OK. Then, you put the coverplates on and the pressure they exert at the top of the reedplate seals a leak along the top of the reedplate, thus making the whole thing play crappy.
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www.elkriverharmonicas.com
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MP
200 posts
Apr 24, 2010
11:58 AM
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aslive,
when i check for alignment, i remove the plate,hold it up to the light, and press the reed gently into it's slot. don't want to bend it. when it is in the slot it is easier to see if it is perfect or just clearing the slot.. i use natural light (daylight on a covered porch). i find lamps distort how tight the tolerances are.
like dave says, you can move the reed with a shim. good advice. i prefer a wrench. it's faster and more precise
Last Edited by on Apr 24, 2010 11:59 AM
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