tookatooka
829 posts
Dec 06, 2009
11:11 AM
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Got my Sp20 today and want to open up the backs. Has anyone done this? I'm keen to understand how it is done because the SP20 back isn't flat like the MB, the backs are angled at the ends and it looks like I'd need to cut into the angles to make three flat sections to bend under. I've looked for examples and haven't been able to find any. Anyone know anything?
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isaacullah
481 posts
Dec 06, 2009
12:58 PM
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Yeah, I have. I do it the same way i open the backs of any other harp: with pliers. I'm not to picky about appearances, so I don't care if it's not perfectly flat or if there are a few marks here and there from the pliers. I use ones that don't have "teeth" (ie. they are smooth metal) so it doesn't mar the surface. The kind I use are normal square jaw pliers. There are a few "dents" though from uneven pressure. If I was more careful, I could do a better job, but like I said, I don't care that much about how they look. You'd probably get better results if you used the kind meant for bending sheet metal (they look like clamps).
you don;t need to cut those angled edges, you just crimp them up with the pliers. Needle nose woeks well for this part.
Check the "show us your harps" thread for the pics of my harps to see how it looks. Click the image to go to my image hosting site and a larger version.
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The magnificent YouTube channel of the internet user known as "isaacullah"
Last Edited by on Dec 06, 2009 12:59 PM
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tookatooka
830 posts
Dec 06, 2009
1:04 PM
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Thanks isaacullah, will go and have a look, although I'm beginning to have second thoughts. Forgot I have an amp so don't really need the harp to be very loud.
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GermanHarpist
781 posts
Dec 06, 2009
1:22 PM
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To avoid the dents from the pliers, you can take some softer buffer to even out the pressure. I use a simple folded piece of paper (maybe 5-6 folds). However, you still have to work very carefully.
However, if I had some machine I would probably cut and fold the straight parts.
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germanharpist on YT. =;-)
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rpoe
48 posts
Dec 06, 2009
1:30 PM
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Some good suggestions here.
http://www.harmonicasessions.com/feb08/Pollard.html
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tookatooka
832 posts
Dec 06, 2009
1:38 PM
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Thanks Guys, Still deciding. That info rpoe. I knew I'd seen something about doing that but forgot where I saw it. Thanks.
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nacoran
508 posts
Dec 06, 2009
2:16 PM
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There are rubber covered needle nose pliers you can get. I've only seen them on the Pine Bush Derby website.
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Oliver
113 posts
Dec 06, 2009
3:16 PM
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I used a bit of chamois leather as a buffer when using pliers to open the backs of a MB. No idea about SP20 though, good luck!
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isaacullah
482 posts
Dec 06, 2009
4:57 PM
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Yeah, I've used cloth, leather, paper, tape, etc., but it's all a big pain in the ass. If I was making harps for someone else, I'd take these steps,a nd I'm confident I could make a very smooth and dent free crimp. But personally, all I care about is the SOUND difference. And boy does it make a difference! Especially with the Spec 20's. So Tooka, I think you should DEFINITELY do it. It's pretty easy, and you WILL hear an immediate improvement in volume, tone, and projection. And all you hand techniques will come through clearer too (wha's, cupping, hand vibrato).
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The magnificent YouTube channel of the internet user known as "isaacullah"
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KingoBad
145 posts
Dec 06, 2009
5:06 PM
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Use the true manly way - Duct tape. I put duct tape on the hammer and on pliers to make it scratch free - works like a charm!
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Bluzdude46
303 posts
Dec 07, 2009
7:06 AM
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I have a vise that has the perfect jaw size to do the backs of cover plates you need to load it just right and start turning it, they snap perfectly into place with a nice straight edge
Last Edited by on Dec 07, 2009 7:07 AM
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sorin
108 posts
Dec 07, 2009
9:18 AM
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Some time ago , after reading the pros and customizers talking about open covers sided vents , I decided to give it a try , the result you can see it in the photo :
MODIFIED SPECIAL 20 VS STOCK
But I have found out that I didn't like it at all , yes is louder but the sound is brighter and I don't want that.
Am I the only one that prefers stock covers? ( I mean by choice)
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GermanHarpist
782 posts
Dec 07, 2009
9:45 AM
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That's some beautiful work sorin. How did you do that? Did you cut the metal off?
I think most of us fold it over, I'd think that should reduce some of the brightness.
I don't dislike the somehow duller sound of an closed harp either. But I'll need some (a lot) more experimenting and experiences to find the perfect harp/combination.
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germanharpist on YT. =;-)
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sorin
109 posts
Dec 07, 2009
9:54 AM
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The sided vents were filed down , and the bottom of the covers were grinded down with a Dremmel (rotary) tool.
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congaron
331 posts
Dec 07, 2009
4:32 PM
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I used lineman's pliers with electrical tape to prevent marring. they look stock until you see the back..no marks. I did mine right on the comb..didn't even take the screws out. The plastic nub will flex out of the way or you can take the cover off if you want.
Last Edited by on Dec 08, 2009 9:36 PM
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harpwrench
125 posts
Dec 07, 2009
4:48 PM
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Nice looking work Sorin!
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Ant138
212 posts
Dec 08, 2009
7:36 AM
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I've just tried it on an old £3 harp i had using pliers and a cloth duster, and its worked a treat. I might try it on an old Bluesharp and see if it works as well. Not sure if i should attack my Seydel Solist pro's just yet but its alot easier than i thought it would be.
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jawbone
178 posts
Dec 08, 2009
8:05 AM
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I grind 'em down on a bench grinder as well - just be gentle and don't get them too hot, I quench mine often.
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If it ain't got harp - it ain't really blues!!!!
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isaacullah
483 posts
Dec 08, 2009
8:10 AM
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Ant, I did one of my two Soloist Pros (check out the pictures in "show us your harps"). Their covers are thicker than Marine Bands, and even than Spec 20's (which have pretty thick covers). They were fairly difficult to bend, especially to do neatly. However, I, of course, didn't really try all that hard to do it neatly. IMO, it made a significant improvement.
I like a bigger, more projected tone. However, I think I understand what Sorin is talking about, that sometimes you want that more "muted" tone back. IMO, however, you can "regain" that original "muted" tone he likes by using hand techniques (tight cupping). It's there whenever you want it, but it's not there "ALL the time". There's no hand technique in the world that's gong to make a closed back, muted harp sound like an opened back, bright, more projected harp, however. With an opened back harp you just have more tonal options.
I also take a pair of needle nose pliers, and "tweek" the sides of the covers so that the opening is larger. On a marine Band, I just grab the sides (where the vent is) and give it an outward twist. This has the result of moving the covers outward from the comb a bit. On Spec 20's and Seydels, I have to put the pliers in the corners (near the ends) of the coverplates, and I give it an outward twist and a pull up. Same effect. In the end, there is more space where the covers open in the rear of the harp, more resonant space "inside" the covers (between the covers and the reedplates), and better projection of the sound (ie. outward towards the audience). To me, this just makes for a better sounding harp.
It just strikes me, that maybe what Sorin is referring to is that with an opened back harp, you cant hear yourself as well as with a closed back one. This would make sense because with an opened back one, you are projecting more of the sound away from you. Whereas with a stock, closed back one, the lips of metal hanging down from the back of the coverplates are keeping more of the sound in the harp, some of which eventually reverberates back out the holes towards you and your ears. Just a thought, anyway. Perhaps the best way to tell would be to record the sound of a melody played on both types of harps with a mic set at some distance in front of the harp, then make an opinion of what sounds better to you....
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The magnificent YouTube channel of the internet user known as "isaacullah"
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barbequebob
175 posts
Dec 08, 2009
1:46 PM
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Whenever you open up the back covers or emboss the reed slot tolerances, they will make a harp play much louder and brighter, so often times playing softer can be the answer. If he's tuning to ET, I'd rather have the more enclosed back to cut down the harshness of the chords tuned that way.
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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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isaacullah
487 posts
Dec 08, 2009
3:39 PM
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BBQ: Can you not "simulate" the effect of normal coverplates on a harp with modified coverplates by changing your cupping technique (perhaps along with softer playing, etc.)? I was just sitting around here today doing that. The only issue is that I don't have two of the same key harps where one has opened backs and the other doesn't (not two functional harps anyway), so I can't really tell if I'm getting close to simulating the closed back sound with my hand technique...
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The magnificent YouTube channel of the internet user known as "isaacullah"
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sorin
112 posts
Dec 12, 2009
7:43 AM
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Isaacullah quote :
"It just strikes me, that maybe what Sorin is referring to is that with an opened back harp, you cant hear yourself as well as with a closed back one. This would make sense because with an opened back one, you are projecting more of the sound away from you. Whereas with a stock, closed back one, the lips of metal hanging down from the back of the coverplates are keeping more of the sound in the harp, some of which eventually reverberates back out the holes towards you and your ears. "
It's an interesting observation ,and it might be valid with an open back harp , but because mine has side vents also , that is not the case .You can hear yourself extremely well ( that was the only thing that I liked after modifying it), the sided vents act like some monitors... the sound comes right back to your ears.
Another effect of the side vents is that the hand effects get toned down a bit , which it looks like a bad thing but it can have a good use in one application , when recording the harp acoustically .I do not have a compressor so when I record , and go from a tight cup to an open cup , it will distort the sound ,but with the side vents the level is more constant , the changes are not that dramatic.
Last Edited by on Dec 12, 2009 7:43 AM
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barbequebob
197 posts
Dec 12, 2009
10:37 AM
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You really can't because the two are really very different.
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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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