Air leaks in valve circuits and intonation on open bugle notes

[gocsick]

Ok here is a question that has me thinking. Can an air leak on an unused valve circuit cause intonation or stability issues on notes that don't enage that circuit.. open bugle note for instance... Intuition no.. because a vented valve is basically a deliberate leak... but I am wondering because the Google AI basically told me otherwise. I don't really believe the AI but my intuition has also been wrong on many occasions....

Google's answer
"Even when a valve isn't pressed, the tubing and valves form part of the overall air column and must seal completely. If there's a leak in the fourth valve circuit, air can escape or turbulence can be introduced even when the valve is up. This can: 1) Slightly alter the resonance of the entire instrument. 2) Affect the slotting and pitch center of open notes. 3) Create a subtle backpressure irregularity."

Nonsense or truth? Is my intuition wrong or is the AI hallucinating?

[arpthark]

That sounds bunk to me. Experiment by removing tuning slide(s) and playing around on the horn without using the affected valve(s). I think you'll find no difference.

[gocsick]

That sounds bunk to me. Experiment by removing tuning slide(s) and playing around on the horn without using the affected valve(s). I think you'll find no difference.

That's how you know I am a professor. I spent time doing fluid dynamics calculations instead of just opening a water key on on a valve circuit while blowing..

[the elephant]

No. It is 100% untrue. Remember that at the bottom of the section, it says that the AI is experimental and that it could be incorrect. Well, it is absolutely incorrect. It sounds like it scanned some of those lunatic trumpet forums.

Venting valves correctly is 100% okay to do.

[bloke]

No. It is 100% untrue. Remember that at the bottom of the section, it says that the AI is experimental and that it could be incorrect. Well, it is absolutely incorrect. It sounds like it scanned some of those lunatic trumpet forums.

Venting valves correctly is 100% okay to do.

Thoughtful people point out the dangers of both relying on AI and allowing AI to make important decisions.
AI tends to assume that consensuses are truth, much in the way that some people who believe themselves to be scientists do the same thing. Having read a few history books, I can think of some consensuses from the past that the world's most powerful and respected scientists all decided (as consensuses) were truth - things at which even most burger flippers today would scoff.

The noun "consensus" and the adjective "settled" have no places in science. This is Rod Serling "Twilight Zone" stuff.

To the topic (rather than to the general), switches, breakers, and fuses isolate electrical flow and cutoff valves isolate water flow. Piston valves and rotary valves on brass instruments are nothing more than backwards cutoff valves.

[MiBrassFS]

Another “AI fail.”

[BramJ]

All AI does is read text and, based on that, create new text. It follows the rules of writing/grammar/spelling and that helps in making the answer sound convincing, even though it is completely wrong.

Use it wisely, if it gives you an answer ask for the source and read that to verify

I guess this answer is based on a leaky valve discussion somewhere, the valve circuit does become part of the air column in that case

Ask an image generating AI to create an image of an analog watch at a specific time, good luck in getting something else then 10:10. Pretty much all photos of watches on the internet have the watch hands at 10:10

[UncleBeer]

Google's answer
"Even when a valve isn't pressed, the tubing and valves form part of the overall air column and must seal completely. If there's a leak in the fourth valve circuit, air can escape or turbulence can be introduced even when the valve is up. This can: 1) Slightly alter the resonance of the entire instrument. 2) Affect the slotting and pitch center of open notes. 3) Create a subtle backpressure irregularity."

There's a nutty misconception among brass players (even among pros) that fluid dynamics play a part in how a brass instrument works. Very little air goes into a brass instrument, and very little air comes out. Brass instruments are essentially echo chambers, and well-designed instruments fortify the formation of acoustical standing waves, which produce notes, bouncing back and forth between lips and the bell. "Disruption of air flow" and "turbulence" are just buzz words for those who don't understand how instruments work.

I tend to cast a very skeptical eye towards all things AI. I wish it wasn't being shoved down our throats before it's actually working properly.

[MiBrassFS]

Well… yes and no… fluid dynamics are in play here. Just not how people want to connect it to acoustics. The “fluid” in this case is a gas. The gas being the air inside the instrument. Sound waves travel through the gas which is confined by the defined column of the instrument. That definition affects what will come out the bell. What’s coming out the bell just isn’t delivered by the blowing of “your air.”

[UncleBeer]

Well… yes and no… fluid dynamics are in play here.

Disagree. If that were strictly true, you'd notice a HUGE difference every time you engaged that 180 degree hairpin turn called your 2nd valve. Perhaps you do; I don't.

[bloke]

100% on @UncleBeer

Our band directors and studio teachers talked to us about "air air air," but - in reality, when we play - we close our mouths down and we do everything we can do to keep air from escaping our bodies into our instruments. "Echo chamber" is absolutely right: The air in our tubas hardly moves (though it certainly does vibrate), and we make it vibrate sympathetically with our lips' vibration.

When we talk about "breath control" to play longer phrases, in reality what's happening (it is my belief) is that we become better and better at getting our lips to vibrate nicely, and it requires less and less air as we become more and more skilled at doing so.

We've (I've?) gone over this before, so I'm being pretty redundant.

I did mention one time that - with one of my tubas (which sports a fairly lightweight 1st slide) - my first valve slide moves under my fingers when I'm really playing loudly. Someone may well come back and tell me that this idea is absurd, but I've got that slide working remarkably well with no more leak than a typical professional instrument's pistons. I dropped that slide assembly down (shortened the first circuit) lower so that when pushed all the way in it will play first valve c in tune (a B-flat tuba), and a couple of weeks ago I realized I wasn't pulling it out far enough for E flats and lower d. I started paying attention, and - most of the time, when that slide was trying to lift under my fingers - it was when I was playing those pitches and (again) you may tell me I'm full of beans but I believe it was trying to lift itself because I was probably lipping those pitches in tune, and the tuba was trying to make itself the length of the pitch I was playing and had a place right there (that slide) which moved easily. Once I corrected my playing habits and pull that slide out far enough to make the tuba truly in tune with those pitches I was vibrating with my lips, that slide quit trying to lift on me... so - as nutty as this probably sounds - I believe it was an acoustical thing causing it to lift, rather than any sort of airflow thing.

Circling back a few sentences, I'm just reminding myself and anyone reading this that - when we cause our lips to vibrate - we are closing our lips mostly down and mostly trying to prevent air from escaping our bodies into our instruments.

I completely realize that the slide phenomenon sounds pretty wild, and I'm totally opening myself up to criticism and mockery. So be it. I'm probably wrong about this, but perhaps not. It won't be the first time that sound waves physically moved an object... and I certainly cannot move that first valve slide simply by blowing air into the tuba, and I'm talking about blowing a lot more air into the tuba than when my lips are vibrating.

I suspect if I taught any tuba players private lessons, other teachers (as there's an awful lot of groupthink in any profession) would scoff at me even more than they do, yes? ...yet - if I'm so off base, why is it that I'm able to play well enough for people to call me and offer me money to play the thing and put tracks on their recordings...

[Mary Ann]

Welp as usual I like to point out the little things. It did say "must seal completely" which means if your ports are not lined up, it would play lousy. Not that I have any confidence in what a computer drags out of the controlled online data, but that is a valid point.

[MiBrassFS]

Vibration is traveling through a defined column of gas. By definition, fluid dynamics are in play. Gas doesn’t cause the sound, vibration does. The shape of the gas (along a few other things like temperature and density…) affects the resultant sound.

[bloke]

There's very little "flow"...

Believe this, or don't believe it...

======================================

Hand me a 186 (I'm frankly not sure I can do this with a 6/4 tuba...It might not work or might be easier ?? with a 6/4-size instrument).

Put a lit match up at the bell opening...roughly at rim level, centered on the bore.

I can huff and puff "plain air" (no lip vibration) into the mouthpiece all day (probably even from a compressor hose), and that match will burn the fingers off the person holding it there...

...BUT, If I press down all the valves (something like a thirty-freakin'-feet-long air column), and super-percussively-ffff blatt a medium-high-range pitch very short, I can probably blow out that match with the VIBRATION. (OK...I haven't done it in a long time, but I could do this back when I tried it...and showed others as a "trick".)

bloke "It's not air flowing that snuffs out the match. Rather, it's the disruptive burst of vibration. Sure: Something has to be there to vibrate...It's the air that's already in the tuba, not the air I'm blowing into the tuba, and not much of anything to do with the air in the tuba moving out of it, either."

EDIT: ANYONE and/or I can think all sorts of wrong stuff about what's occurring, as long as we DO good things that need to happen to make GOOD sounds.

[MiBrassFS]

As I said in my first post that is being ignored. The traveling air isn’t causing sound. The vibration traveling through the defined gas column is causing the resultant sound.

You can hook up a door buzzer to a mouthpiece which will introduce zero airflow into an instrument’s define air column and the vibration from the buzzer still travels through the defined column of gas and will produce a sound. It won’t be a very characteristic sound, but the laws of fluid dynamics are still in play because the shape of the gas as defined by the column (the tuba…) will affect the resultant sound.

Believe it or not.

[bloke]

no argument with that - none whatsoever...

...but does a vibration transferring itself through a (mostly stagnant) column of air fit very well into the category of fluid dynamics?

[MiBrassFS]

no argument with that - none whatsoever...

...but does a vibration transferring itself through a (mostly stagnant) column of air fit very well into the category of fluid dynamics?

Yes, 100%. The air/gas doesn’t have to move through at all. Only the vibrations have to. Putting a beach ball the bell limits the travel of the vibration and limits (or ends if the vibration is also ended) the resultant sound.

[bloke]

no argument with that - none whatsoever...

...but does a vibration transferring itself through a (mostly stagnant) column of air fit very well into the category of fluid dynamics?

Yes, 100%. The air/gas doesn’t have to move through at all. Only the vibrations have to. Putting a beach ball the bell limits the travel of the vibration and limits (or ends if the vibration is also ended) the resultant sound.

We completely agree.
I've said before (and - of course - there is NOT) that WERE THERE some way to get our "double reed" (lips) to vibrate WITHOUT blowing air past them, the tuba would sound...(OK...maybe... )

[peterbas]

Got a wake-up call that informed me that some of the discussions on the more scientific level of the tuba seems to have paid off a little.

[the elephant]

The future is now.