Rampless Chromatic Comb

[harpdog123]

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

[winslowyerxa]

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]

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

[FrankTetsche]

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

[Brendan]

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 (199.2 KiB) Viewed 16824 times

[mayeran]

Can you answer how has the sound changed with this type of construction?

[Brendan]

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.

[harpdog123]

Just got a batch from the machinist. This is the first time I've used a machinist and I am thrilled with the results!

[Brendan]

Very nice!

[CrawfordEs]

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.