Rampless Chromatic Comb

Anything apart from the two mainstream default harmonicas (Solo-tuned fully-valved chromatic, and un-valved Richter 10-hole diatonic). Alternate tunings, different construction, new functionality, interesting old designs, wishful-thinking... whatever!
harpdog123
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Rampless Chromatic Comb

Post by harpdog123 » Wed Apr 26, 2017 5:38 pm

I've designed a chromatic comb without ramps. I've tested some prototypes and I didn't notice a difference between ramped and rampless combs. What would be the negative effect of a rampless comb? Would the hard edges of a rampless reed chamber add noise when a player breathed into it? (I've attached a pic of my design)

David Pearce
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rampless comb.png
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winslowyerxa
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Re: Rampless Chromatic Comb

Post by winslowyerxa » Thu Apr 27, 2017 12:04 am

I see ramps - those raised floors on the chambers

On higher pitches, a large chamber can drag pitch down if its resonant frequency is lower than that of the reed.

Ramps also reduce the air required to fill the chamber before it starts moving the reed, allowing for quicker response and less breath requirement.

harpdog123
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Re: Rampless Chromatic Comb

Post by harpdog123 » Thu Apr 27, 2017 1:48 am

Hi Winslow, When I say ramps I mean the angled face that many chromatic combs have in the reed chamber like this. What is the purpose of these angled faces? I assume that it facilitates airflow into the reed chamber, but in the testing of my prototypes I haven't noticed a difference between an angled face and one that's 90 degrees. Eliminating the angles would make machining much easier.

David Pearce
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Comb with Ramps.jpg
Comb with Ramps.jpg (78.09 KiB) Viewed 1404 times

FrankTetsche
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Re: Rampless Chromatic Comb

Post by FrankTetsche » Sat Apr 29, 2017 5:01 pm

Hi David. Here is what I think. No one has thought about a purpose for angled faces. That's just the way it went. Can you bend notes? If you can, I see no problem with your comb.
Frank Tetsche

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Brendan
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Re: Rampless Chromatic Comb

Post by Brendan » Sun Apr 30, 2017 11:23 pm

Looks like the Easttop brass chromatic combs, David :-) They have the integral front lip also. You must have access to a nice CNC machine to make your design, if you're doing it in metal.

Comb ramps should rightly be called Tate Ramps, because Douglas Tate was the one to invent them. All they do is take chamber-volume reduction to the logical conclusion of what's possible, using the reed directions as a guide.

But what matters is how the instrument sounds and plays. Your raised floors are reducing chamber volume quite a bit, so that's the main thing.
Easttop Brass Chroms13a.jpg
Easttop Brass Chroms13a.jpg (199.2 KiB) Viewed 1360 times

mayeran
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Re: Rampless Chromatic Comb

Post by mayeran » Wed Jun 07, 2017 1:32 pm

Can you answer how has the sound changed with this type of construction?
I father taught me how to play harmonica. And I am very grateful to him for this

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Brendan
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Re: Rampless Chromatic Comb

Post by Brendan » Sat Jun 10, 2017 3:56 am

Several years ago I asked Chris Reynolds to make me a quite radical chrom comb without any transition between the slider and the chambers (see photos). The slide and backplate provide a transition by themselves. It works well.
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Backplate & Slider On.jpg
Backplate & Slider On.jpg (157.4 KiB) Viewed 1151 times
Modified Comb Assembled.jpg
Modified Comb Assembled.jpg (193.14 KiB) Viewed 1151 times

harpdog123
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Re: Rampless Chromatic Comb

Post by harpdog123 » Mon Jun 12, 2017 3:51 am

Just got a batch from the machinist. This is the first time I've used a machinist and I am thrilled with the results!
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Comb 3.jpg
Comb 3.jpg (163.65 KiB) Viewed 1123 times
Comb 2.jpg
Comb 2.jpg (158.43 KiB) Viewed 1123 times
Comb 1.jpg
Comb 1.jpg (173.07 KiB) Viewed 1123 times

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Brendan
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Re: Rampless Chromatic Comb

Post by Brendan » Mon Jun 12, 2017 7:49 am

Very nice!

CrawfordEs
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Re: Rampless Chromatic Comb

Post by CrawfordEs » Tue Jun 13, 2017 1:31 am

That looks pretty sweet.
I'm interested in that hole in the back?
Is that going to have a coil spring inside that hole on the back?
It looks to me like it should work almost like a ballpoint pen if you have an arm on the slide that extends back there.
Or I could just be imagining that.

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