Water key...

[bort]

Interesting idea. Maybe better suited for horns that don't sit (and drain) into your lap...

Also, I'm not crazy about needing replaceable parts like that... not like cork or rubber stoppers last forever, but you can be certain that every repairman in the world always has those parts.

[Dan Schultz]

So you basically have a 'leak' all the time?

[PMeuph]

... not like cork or rubber stoppers last forever, but you can be certain that every repairman in the world always has those parts.

...or every liquor store...

[Cameron Gates]

"Imagine being able to eliminate the centuries old problem and the associated stress caused by water building up in brass instruments from your playing experience."

Stress?

Someone is taking horn blowing way to seriously.

[iiipopes]

As a guy, well, the thought of a constant dribble is less than....

[arminhachmer]

If it leaks water, it will leak air. Where is the JOY in that?
If all the trumpets sitting behind my wife used them and stopped blowing the spit valve every
90 seconds, she would be happier and i know she would not give a rats derriere where the joy
valve might deposit its stress reducing drip in the trumpet players lap.

[hup_d_dup]

If it leaks water, it will leak air.

I don't think this is true. The mechanism is described as a wick. If it works properly, the surface tension of the water in the wick should provide a seal against air.

Hup

[Rick Denney]

If it leaks water, it will leak air.

It's not a question of whether it will pass air, but rather at what frequency of vibration it will pass air. If the air is "DC" (constant pressure), then anything that moves water will move at least some air, though it could be a high resistance.

But if the air is wiggling back and forth at some acoustic frequency, which is how it really is, then water in the opening might well provide a wall against that vibration leaking out and undermining resonance. In the electronic world, we'd call this high impedance, with impedance being resistance at a particular frequency.

So, the trick for this concept is a vent that provides low impedance at zero frequency and high impedance at frequencies in the acoustic range. For tubas, that starts at a few Hz.

Example: Valves leak water routinely--it's what makes water spray out the bottom of the casing. The clearances are more than big enough to move water at very low or zero frequency. But that water also fills those clearances and prevents leakage at higher frequencies. When we conduct the "pop" test, we are assuming that a good seal in the range of 0-1 Hz will mean a good seal at frequencies in the acoustic range. But a valve that "fails" the pop test can still provide good service. That's why the better test is to use a thicker oil, which fills those gaps and provides high impedance at lower frequencies, to see if resonance improves, to determine whether leakage is critical.

As always, I worry about mechanical integrity. Simplicity is important.

Rick "lost in the frequency domain" Denney

[hup_d_dup]

It's not a question of whether it will pass air, but rather at what frequency of vibration it will pass air. If the air is "DC" (constant pressure), then anything that moves water will move at least some air, though it could be a high resistance.

It isn't clear to me that this describes the working mechanism of this water key. It is a wick, so it doesn't act by pressure, like a hose, but by capillary action, like the capillaries in a tree which can move water from areas of high pressure to low pressure. In any case, the difference between the atmospheric pressure inside the tuba and outside are so minuscule as to be overwhelmed by capillary action.

The way I see it is the wick soaks up water. Liquids have surface tension, gases do not, so the wick collects water and displaces air. The water is not being pushed out of the tuba, it is being soaked up, like a sponge. When the wick is fully soaked, water accumulates on the under part of the outside surface. The rough surface of the "key" breaks the surface tension of the water and then gravity takes over. As water drips from the bottom of the key, more is soaked in from the top.

Surface tension at the dimensions of a wick is very powerful, much more powerful than gravity or the air pressure inside a tuba. Can vibration overcome this surface tension? I don't know but I would be surprised if enough acoustic energy is released right at the point of the water key to overcome the surface tension.

My theory.

I think Bloke is right that mineral deposits will be a problem with this water key.

Hup

[hup_d_dup]

Another problem that occurs to me with this water key is the rate at which the water leaves the horn. It's a wick, so the water isn't going to pour out. If you spin your tuba to get water to the key, that water may sit above the key for some time as the key drip, drip, drips it out.

(Or you have to pull the slide and it's not such a convenient solution after all.)

Hup

[Highpitch]

I sort-of understood the theory. What then occurred to me is that it could end up being clogged with lime deposits.

How many limes do horn player usually eat? Maybe proportional to the number of Margaritas imbibed?

DDG

[Kevin Hendrick]

I sort-of understood the theory. What then occurred to me is that it could end up being clogged with lime deposits.

How many limes do horn player usually eat? Maybe proportional to the number of Margaritas imbibed?

DDG

"I vill not buy this Margarita -- it is scratched!"

[Rick Denney]

It's not a question of whether it will pass air, but rather at what frequency of vibration it will pass air. If the air is "DC" (constant pressure), then anything that moves water will move at least some air, though it could be a high resistance.

It isn't clear to me that this describes the working mechanism of this water key.

What I wrote doesn't argue against what you wrote. A wick is just a high-impedance filter. But if it was dry, it would move air, being porous, if there was a static pressure difference. The acoustic-frequency impedance might even be too low for a porous wick if dry.

Dry valves can lose their impedance, too, and they seal using the same capillary surface tension you describe. In fact, that's what keeps them lubricated and riding on a film of liquid rather than rubbing metal on metal.

Rick "just a matter of scale" Denney

[tbn.al]

At the end of the concert, I believe I would rather walk away from a wretched, nasty, wet floor in clean, dry pants than the reverse.

[Rick Denney]

I sort-of understood the theory. What then occurred to me is that it could end up being clogged with lime deposits.

At the rate my horn seems to build up slime (despite fairly disciplined attempts on my part to prevent it), I suspect lime buildup would be too slow a failure mode.

Rick "time for a scrubbing" Denney

[MartyNeilan]

This is also my reservation on trying the Saturn water key. The plastic ring component seems to be a weak spot that can't easily be fabricated in the event of failure and lack replacement part supplies.

I had a Saturn water key put on the "dogleg" going into the horizontal main tuning slide on BART to replace the original style main water key. To me, I believe it slightly helped the low 4th valve G that can tend to be just a little fuzzy on larger CC tubas.
However, I did find out that the plastic ring can melt!
I replaced the tuning slide, and when I soldered the new outer slide onto the dogleg, enough heat was transferred to deform the tips of the ring that displace the ball, so that it would no longer let any water out when pushed. My fault for not disassembling the saturn water key before doing major work on the horn. I called HornGuys, and ordered a new ring along with two more saturn keys that I will eventually put on my 3rd and 4th crooks.
The designer of the saturn key said that is the first time he heard of the plastic melting.