mikolune
73 posts
Feb 01, 2011
8:15 PM
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I've had this question for some time now.
In holes 1-6, for example, why isn't it possible to blow bend-up the note, in the same way that we bend down the draw note ? Can't we blow bend to get a note in between the natural draw and blow notes ?
Note that I am not talking about overblows.
Is this because the reed positioning compared to the comb ? (reeds are attached comb side on top, and cover plate side on bottom). Or am I missing something obvious ?
Physics of the harp never cease to fascinate me.
thanks !
Michel
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nacoran
3762 posts
Feb 01, 2011
11:02 PM
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I can't explain the the hardcore physics. On holes 1-6 the physics allow you to bend the note down with a draw, but since the reeds are flipped from 7-10 the bending is on blows instead.
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mikolune
74 posts
Feb 01, 2011
11:14 PM
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Thanks nacoran ! I fully understand this difference between 1-6 and 7-10.
For simplicity, I asked about holes 1-6, but the same thing would apply to holes 7-10 changing draw to blow.
So, let me repeat. I understand that when you bend a note, you actually get both reeds vibrating (at the same frequency ?) What I am wondering is why can you get both reeds vibrating only when you draw on 1-6 (blow on 7-10) ? Why can't you get both reeds vibrating when you blow (draw 7-10) ?
Possibilities I see:
1) positioning of the reeds with respect to the comb
-> may be we could test this by switching blow and draw reed plate <-- [edited] actually - this can be ruled out because from the 1-6, 7-10 flip, so we are left with:
2) You need the higher frequency reed to vibrate to initiate the bend
Anyone have an idea ?
thx!
Last Edited by on Feb 02, 2011 2:33 AM
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Baker
101 posts
Feb 02, 2011
4:38 AM
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As far as I understand it, the because of way both reads are working together you can only get notes between the two reeds that are working.
eg. 2 hole of a C harp: blow is E – draw is G there for the notes available to bend are the two between them, F# and F.
8 hole: blow E – draw D the blow bend available able is the note between – Eb.
The flatter you go on a draw bend the more the blow reed is working, and on a blow bend the flatter you go the harder the draw reed is working.
Last Edited by on Feb 02, 2011 4:41 AM
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mikolune
75 posts
Feb 02, 2011
4:42 AM
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> eg. 2 hole of a C harp: blow is E – draw is G there for the notes available to bend are the two between them, F# and F.
Ok! so my question is: why can't you bend the E up to the F or F# *blowing* in the 2-hole ?
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Andy Ley
77 posts
Feb 02, 2011
4:49 AM
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I guess it's because bending can only slow down the vibrations of a reed; producing a lower pitch, but can't increase the vibrations to produce a higher pitch.
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MrVerylongusername
1542 posts
Feb 02, 2011
4:58 AM
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I think you're onto something with the theory of needing a higher freq reed to kick start the bend. IIRC that's the principle of the XB-40 which has 'enabler reeds' riding shotgun with every main blow and draw reed.
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Baker
102 posts
Feb 02, 2011
5:01 AM
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@ mikolune – It is a good point. I am unsure of exactly how it works from a physics point of view. For instance, on a draw bend if you are slowing the speed of the vibrations of the draw reed, are you also speeding up the vibrations of the blow reed so they meet somewhere in the middle, or is the blow reed vibrating as it normally would and mixture of the two reeds working together at two different speeds is what causes the change in pitch?????
Last Edited by on Feb 02, 2011 5:04 AM
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Andy Ley
78 posts
Feb 02, 2011
5:04 AM
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That was going ot be my next hypothetical. What would happen if you had 'dummy reeds' that you couldnt blow/draw yourself, but could interact with the reeds in the slot? Now I know.
Not suggesting that harmonica makers should re-invent the wheel, I've just always found this interplay between the two reeds while bending to be a facsinating subject.
God I need a life!
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Baker
103 posts
Feb 02, 2011
5:23 AM
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At a guess I would suggest it was probably the later, a mixture of the two reeds working together at two different speeds causing one combined pitch. This is why you are "trapped" between the two notes, weather you are draw bending 1-6 or blow bending 7-10.
Also, this interesting article was posted in a recent thread on overblowing. http://archive.harmonicasessions.com/dec04/overbends.html. Check out the overblow chart (http://archive.harmonicasessions.com/dec04/Overbends7.jpg) and the amount of notes available on the 6 overblow once you have learned to bend overblows (up). This would suggest that once "freed" from the other reed in the slot a single reed can have a huge range.
He also states that "Recently, I learned it is also possible to overdraw holes 1-6 and overblow holes 7-10". I guess this is similar to what the OP is alluding to. It means on holes 1-6 he is able to get the blow reed to respond at a higher pitch while drawing (vise versa for holes 7-10), however it is done using the overblow technique which means there is a need to choke the draw reed.
EDIT: No wait, sorry, you still can't go flatter than the blow reed on holes 1-6.
Last Edited by on Feb 02, 2011 5:29 AM
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harpdude61
714 posts
Feb 02, 2011
6:53 AM
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You bend down from the higher pitched reed...1-2 draw and 7-10 blow.
Holes 5 and 7 only have 1/2 step between the two notes of the hole so bending these is just for effects.
Overblows hole 1-6...overdraws 7-10.
No overdraws on holes 1-6 and no overblows on 7-10
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chromaticblues
553 posts
Feb 02, 2011
7:08 AM
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@ Mikolune What you were describing is how chromatics bend on the blow notes. You can bend the draw and the blow notes down because they are isolated from each other via windsavers. If your not familiar with Chroms, windsavers are like little check vales. They only allow air to pass thru the reed your playing (draw or blow).
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mr_so&so
404 posts
Feb 02, 2011
10:29 AM
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I betcha Brendan Power is the fella to answer this one. How do you explain the bending properties of the PowerBender tuning vs. Richter? Brendan has to have that nut cracked.
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chromaticblues
559 posts
Feb 02, 2011
11:16 AM
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Thats easy mr so&so. The power bender has the draw notes higher than the blow notes on all of the holes. The richter tuning (AKA diatonic harmonica as we know it) has the draw notes higher on holes 1 thru 6 and the blow notes are higher on 7 thru 10. Thats why the blow bends on the highend go down in pitch similiar to 1 thru 6 draw notes. The 6 draw on the power bender is the same as the 7 draw on the richter tuning. The draw 7 on the power bender is the same as the draw 8 richter tuning. You see it just moves the draw note down one hole to keep the draw note higher than the blow note. The blow notes are the same. Its a pretty cool idea. I haven't played one, but I have made alternate tunings myself in the past and I like the draw bends on the highend.
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Greyowlphotoart
426 posts
Feb 02, 2011
11:35 AM
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@Chromatic Blues I understand that bending notes on a diatonic was never envisaged when the harmonica was invented and it was a happy accident that led to this marvellous capability, now extended even further with the more regular use of the Overblow and Overdraw.
Do you happen to know the reasoning that led to the blow being pitched higher than the draw through holes 7 to 10.
 Grey Owl YouTube
Grey Owl Abstract Photos
Last Edited by on Feb 02, 2011 11:36 AM
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chromaticblues
560 posts
Feb 02, 2011
12:24 PM
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@ Grey Owl Thats a good question. I think the answer is a two part answer.
1st you already answered your own question without knowing it. The music of the time was played in first position. So the one thing the harp had to have was the first position chord thru out the harp. OK, but the richter tuning and the power bender both have that. As you mentioned people didn't bend notes at that time and all the major notes of the diatonic scale can be played without bending playing 4 thru 7. There were alot of different tunings in the early 1800's. Some of them are interesting. Some are useless. I invented a tuning about twenty years ago and it was in the American Harmonica Newsletter. If anyone out there has any old American Harmonica Newsletters hanging around. Look for Harmonica tunings by Kevin Baker. Then please post them with the Date! I can't remember for sure, but I think it was the Power Bender! I had two tunings. The other was take off of the chromatic.
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mikolune
76 posts
Feb 03, 2011
6:05 AM
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@all: thanks for your answers and comments. So, from what I gather, impossibility to bend up is related to the fact that you can't make the draw reed start vibrating from the slow blow reed.
@Baker - wow - pretty impressive list of achievable notes for bending up the overblow ... This got me wondering - why can the 6 overblow be bent up 6 scale degrees (from G up to E) and the 4 overblow can be bent up only 4 scale degrees. Shouldn't't it be the same, 'cause there's a whole tone between draw and blow for both holes (I admit I haven't read the article tho)
@chromaticblues: if I understand what you say, in the chromatic (or valved harmonicas for that matter) the bending works on a different principle than the standard diatonic ?
@Greyowlphotoart : yep - good question about that particular choice for the Richter tuning. I've been wondering myself :)
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chromaticblues
561 posts
Feb 03, 2011
7:07 AM
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@mikolune Yes that is correct. The reeds don't work in unison because the valves isolate them. All the reeds that are valved bend down.
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