V-Cup mouthpieces

Brent · Posted: Sat Jul 14, 2012 6:13 am Post subject: V cup

Stork mouthpieces also have a 'V' shaped cup. Their rims generally are narrower. Their website is pretty informative.

Brent
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Brent

razeontherock · Posted: Sat Jul 14, 2012 9:23 am Post subject:

I've been playing a V cup since I got it. Love the thing! Lets you absolutely drill end high notes - must be that funnel thing going on. Played in such a fashion, mellow or lack of penetration is NOT how I would describe the way it performs for me.

It's every bit as shallow as Greg Black's S cup, which happens to be the same depth as his M cup, which is confusing. That measuring point, where cup and venturi intersect, really doesn't affect my face at all. People are talking about alpha angle, but what about the length of that angle, aka depth to which that angle goes before other contours take over? A deep V cup will have that angle go in quite a ways, and then when it does transition to a different contour it is so gradual that ... well that's just an entirely different beastie than what I'm playing. I've got the length of that alpha angle about as short / shallow as I can play, and it definitely seems to be a combination that's working for me. Not only lead / high / bright, but the ability to color the sound as well.

etc-etc · Heavyweight Member Joined: 19 Jan 2008 Posts: 3996

It is not the turbulence of the air, because:
Re = ρ u L / μ
ρ, air density 1.225 kg/m^3
u, air velocity 2.39 m/s (6 liters per 60 seconds through a Bach 3C throat)
L, characteristic length 3.65E-3 m (throat diameter of a Bach 3C)
μ, air dynamic viscosity 1.983E-5 kg/(m*s).
This gives a Reynolds number approx. equal to 540 (laminar).

The number above is for incompressible flow. One can argue that the flow in trumpet mouthpiece is compressible - please go ahead and calculate.

The brightness of sound is caused by sudden stopping of the lip while hitting the cup. The sudden stop causes the sinusoidal motion of the lip to be augmented with higher harmonics, resulting in a "brassy" sound. This effect is more pronounced for shallower cups and for greater volume of sound.

geezer · Veteran Member Joined: 22 Mar 2012 Posts: 166

etc-etc · Heavyweight Member Joined: 19 Jan 2008 Posts: 3996

Thank you, that is a good observation/correction.

Even if the lip does not hit the cup on the "out" phase of its vibration, the proximity of the cup wall changes the motion of the lip, making it a more-or-less abruptly flattening out sine.

A good illustration of this would be to record the waveforms at different dynamics and see what happens at the maximum (positive) and minimum (negative) displacement of the microphone diaphragm. In digital signal processing, a more annoying but similar phenomenon is clipping of the signal.

One could test this with lipstick to see what areas of the cup get in contact with the lip, at different dynamics. One would have to apply a very thin layer of lipstick (to the cup! - perhaps different colors to different parts of the cup), and see whether any of color gets transferred to the lips.

zackh411 · Posted: Sun Jul 15, 2012 12:04 pm Post subject:

razeontherock · Posted: Tue Jul 17, 2012 10:50 pm Post subject:

I would go so far as to say how the airflow is compressed has everything to do with every performance characteristic

etc-etc · Heavyweight Member Joined: 19 Jan 2008 Posts: 3996

For compressible airflow, one has to find the formulas - do you have any approximations?

zackh411 · Posted: Wed Jul 18, 2012 11:01 pm Post subject: