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As the title says, basically. Could you have some kind of musical instrument powered by a jet engine?

It could be an organ, or a tuba, or whatever, it doesn't matter.

I'm understanding and open if the answer is "yes, but only if it's the size of a semi truck".

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    $\begingroup$ In real life, the gas turbines which power lots of electric power generators are jet engines, just a little modified to work for their intended purpose. And they power lots and lots of electronic musical instruments. $\endgroup$
    – AlexP
    Nov 15, 2023 at 23:27
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    $\begingroup$ From The Hunt for Red October, "Can you fire an ICBM horizontally? Sure! Why would you want to?" A good-sized jet engine would facilitate the world's lowest octave tuba - but what would be the point of generating a sound that would shatter windows a hundred miles away but humans couldn't hear? $\endgroup$
    – JBH
    Nov 16, 2023 at 1:44
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    $\begingroup$ See pyrophones. I don't think they've been made for jet engine temperatures and pressures yet. Maybe you could have a combo pyrophone/afterburner. $\endgroup$
    – Atog
    Nov 16, 2023 at 2:24
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    $\begingroup$ @JBH Surely the point would be "to shatter windows a hundred miles away without humans hearing" $\endgroup$ Nov 16, 2023 at 10:19
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    $\begingroup$ You could just power off the jet engine, and have it perform John Cage's 4'33". $\endgroup$
    – Abigail
    Nov 16, 2023 at 16:57

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It's very possible, it has been done, and they don't have to be humongous!

It depends a little bit on your definitions, but what you are looking for is a pulse jet engine. These work by detonating some fuel in a pipe, letting the fume blow out the ends and exploiting the resulting slight vacuum that follows to draw in new air. They then set off new explosions at a frequency that resonates with the acoustic length of the tube. The two main types are valved and unvalved pulse jet engines, where the latter are also called acoustic and make all this happen without moving parts, solely relying on the geometry of the tube!

There are many ways of varying the tone and dynamics to potentially produce music.

The most obvious one would likely be to just make a bunch of them and tune to different frequencies, like this one: https://www.youtube.com/watch?v=-zU4u7SSDKw

In theory, you could try yo vary the length of the outlet tube to change the resonant frequency, but this is complicated by it turning very hot. It might be possible though. A simpler way would be to change the length of the inlet pipe. Take a look at this "pulse jet trombone":

https://www.youtube.com/watch?v=FOI0vAK4_4c

My favourite option though, would be to use a long tube and select different overtones using the ignition and variations in the fuel inlet. I can't access this video from where I am now, but I think this shows what I'm talking about: https://www.youtube.com/watch?v=iqknDswOUWA

As for the dynamics and the response of the instrument, I think the videos demonstrate that they should be satisfactory. Especially if someone the time and skills to work on it for a few years.

(I'll try to improve this answer later during the day, as my internet access is a little restricted at the moment)

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    $\begingroup$ Survival Research Laboratories used one of these in their performance in Seattle, June 1990. It was.... interesting. Also loud. Very Very Loud. $\endgroup$
    – Eric Brown
    Nov 17, 2023 at 23:48
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Yes... but No

Okay - bold statement here, definitely not hedging my bets...

So - in terms of the basics - yes, an instrument with a constant flow of air could work.

You might have some technical challenges around things such as needing to 'tune' the instrument to account for the pitch/timbre of the jet flow as is - but that is doable.

However...

Donning my musician hat

If we are just looking at the woodwind/brass section, we have a number of problems:

Phrasing

Sometimes phasing is used to cover up the fact that we humans can't expel our breath infinitely (quick aside to trumpet players and cheek puffing) - but phrasing is also used in a musical context - let's think of the Baker Street sax solo - the first opening phrase is a bold statement, tailing off to the second phrase which reprises the first theme (linking it) but changes the second.

The fade in/out of the phrasing is what makes it sounds musical. Now, granted you could overcome this by having some form of valve system to divert gasses away - but it's still an issue.

Dynamics

A good musician will have a wide dynamics range - again, woodwind and brass section considered here - the ability to go from piano to fortissimo is a skill. A jet engine is very good at sitting at a constant speed - and whilst they can spool up and down relatively quickly, They would not be able to go from quiet to loud quickly.

You could, again, perhaps fix this with a complex series of valves...

Pitch

For some (not all) woodwind/brass instruments, pitch is a function of the valves and also of the musician themselves - being able to go from high to low and do so quickly - for reference here: This is an 'experiment' in DCS world of getting jet engines to spool up - the quickest being 3.something seconds - That's half a 4/4 Bar at 100 BPM. And again - that's the quickest most being 5-6 seconds, so a full Bar. Not only that, but changing the blade RPM (which will change the pitch up and down) will also increase your dynamics - so trying to play high and quiet is an issue.

Double tonguing

Settle down. This is a legitimate musical technique - where you use your tongue to interrupt the airflow to play 16th note or even 32nd note patterns. Think of the William Tell Overture - 'da dadada dadadadad' - that repeated note is double tongued.

Again - possible with valves etc., but good grief we are getting a lot here.

Heat

Instruments don't like getting hot or cold, this is why things like glass flutes used to be popular, because they wouldn't get out-of-tune when they heated up or cooled down - a jet engine produces a lot of heat - that heat is going to be doing some expanding of the pipes if it is made of anything metal (probably can't use wood... Ceramics might work) - and that will do all kinds of weird things to your pitch.

Musicality

This is perhaps a summation of all of the above - but there is more to playing a woodwind or brass instrument that just a constant flow of air, I'm a drummer myself (although did learn piano and can remember a lot of musical theory) - there is so much nuance in how a musician uses their body to play the notes. The speed of transition of the human body is much faster than the speed at which a jet engine (even a small one) can spool up or down - and to overcome all of these challenges would require so much extra valving, it would be incredibly impractical.

A jet engine would be great at providing a drone (like the bagpipes) or a siren - or anything that didn't require changes in pitch or tone or timbre or alike.

That said - I like airplanes, I like jet engines - and so if you want a world where there are jet engine instruments - you could do it - the music would have to be written specifically for the limitations of the instrument - but you could do it.

To conclude - instruments as we know them and music as we know it now - no, a jet engine would not work. But in terms of a raw air-source to make different kinds of music suited to the above limitations - sure, why not

Edit: If Tchaicovsky can use a cannon as an instrument for the 1812 Overture, then you can use a jet engine.

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    $\begingroup$ If I could I would give extra upvote for the Tchaicovsky comment! That is a spot on attitude. 😄 $\endgroup$ Nov 16, 2023 at 8:54
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    $\begingroup$ What about bagpipes? You would have a hard time arguing they are not legitimate instruments, but they are not the first thing I think of dynamic range or double tongueing. $\endgroup$
    – EdvinW
    Nov 16, 2023 at 9:13
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    $\begingroup$ The "but no" at the beginning is giving the impression that an instrument needs to do all these things to be a real instrument (hence the counter-examples in the comments). The answer could be improved by reframing it as "Yes, but with limitations". $\endgroup$
    – jb6330
    Nov 16, 2023 at 14:18
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    $\begingroup$ Almost all of these limitations apply pretty much equally to a traditional church-style pipe organ, which runs off a relatively inflexible source of airflow/pressure (hand-bellows in the past, electric today), and is without question a legitimate and versatile instrument, with a huge classical and modern repertoire. So these are constraints the instruments has to be designed around, but they’re certainly not deal-breakers for something being a real instrument. $\endgroup$ Nov 16, 2023 at 15:50
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    $\begingroup$ the music would have to be written specifically for the limitations of the instrument i mean, wasn't this already kind of the case for medieval organ music which was limited not specifically by the instrument itself but the large almost cavern like spaces it was confined to echo around in? $\endgroup$
    – Michael
    Nov 17, 2023 at 12:48
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Yes, such should be possible.

There are a great number of strange musical instruments in existence, from the octabass to the glass harmonica, from the contrabass flute to the theremin. Additionally, avant-garde composers such as John Cage and George Crumb would often compose unusual pieces, both tonally and instrumentally (for example, John Cage once composed a piece for an 'amplified cactus'...). If your story requires a wood or pipe instrument powered by a jet engine, it wouldn't be the strangest.

(Side note: Your question reminded me of the Helikopter-Streichquartett, a piece written for four helicopters and four violins. Just goes to show that composers are always stretching the limits of music...whether their works are good is another debate.)

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  • $\begingroup$ Only partially correct. Most if not all brass instruments work by the musician "blowing a raspberry", so only instruments that use a reed or whistle arrangement would work. $\endgroup$
    – MikeB
    Nov 17, 2023 at 16:25
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Here is a 1968 article on Flame Amplification. We looked at this when I was at university. It seems that if you use a microphone coil to modulate gas flow to a flame, then the flame can act as an amplifier as well as a speaker. For Hi-Fi buffs ask the time, this was the best amplifier-tweeter you could get, but the efficiency falls off below 2KHz.

My dad told me of a rocket launch he saw in the 60's (?). it was not a pulse jet but it had some anomaly that produced a lot of infrasound. He could not hear the infrasound though his ears told him that something weird was happening to the pressure, and it resonated in the chest cavity and stopped him breathing. He said it was pretty painful, though the effects did not last. So, rocket engines can produce the low notes too.

Any good suggestions for the midrange?

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Yes

An Organ could be powered by a jet engine, with enough engineering... I would suggest using either a miniature jet engine, or only using a small percentage of the air flow from regular sized jet engine. (unless you plan on sound as a weapon, and deafening your audience). There is nothing that stops this from working.

The heat of the exhaust does create a challenge, but it is a solvable engineering problem, which can be solved by radiators to cool off the gas.. Alternative materials with a low coefficient of heat, some type of ceramic probably. actively cooling your organ's pipes. Or even designing the entire assembly to only be in tune once it has warmed up from the heat of the exhaust (though wear/tear from thermal expansion/contraction might make that idea bad, but if this organ is played constantly, that becomes a non issue).

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What immediately came to my mind was the "Large Hot Pipe Organ". Its creators billed it as a "propane-powered explosion organ". Basically, they'd set off small, controlled propane explosions and funnel the resulting blast of air through massive organ pipes. It did produce sound, and was entertaining to watch. It wasn't a particularly effective musical instrument though.

When you scale up to something that extreme, you run into a couple of problems. One of the biggest is that it's typically not safe to be anywhere near it while it's operating. Listeners will be at a distance, and much of your musical sound would have attenuated before they can hear it. Also, the noise of the apparatus itself tends to drown out the musical output. In the recordings of the LHPO you can clearly hear the explosions, but the notes being played are rather faint. People who experienced it in person said that you felt the music more than you heard it. Even at smaller scales, a chainsaw-powered trombone is mostly noise and little music.

A jet engine musical instrument would be much the same. They're literally deafening to be around. You'd be hard-pressed to generate music at sufficient volume to be heard over the engine noise. Even if you managed to do that, it might be the last thing your audiences ever hear. The exhaust gas leaving a jet engine can be near or above the speed of sound, which can make it difficult to create stable, controlled sound waves that survive the abrupt transition from supersonic flow to still air.

All that being said, I have to admit that the idea of a hybrid jet engine/kazoo sounds hilarious.

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The answer has to be Yes based on the principle that anything that can make a sound can be a musical instrument. But I have the sense you are thinking of it as a high-velocity, high-volume airflow source for a wind instrument of some form (understood broadly). And I still think the answer is yes.

I think the most natural type of instrument to use is a whistle rather than a reed instrument or a horn. The latter two work at higher pressures and lower flow rates, and involve vibrating flexible materials that might fail under intense conditions. But that is an engineering question and they could probably all be made to work.

The point here is that getting a high velocity flow of air to make a sound is easy. The hard part is keeping it quiet. And a resonant pipe is a very robust method to specify a pitch. I don't think the rate of airflow from a jet engine is anywhere near the engineering limits of a beefed-up organ pipe.

An organ (which I count as being in the whistle family) seems like an obvious choice.

One downside is that the engine itself is loud. I think (without analyzing it carefully) that the organ would be very, very loud, so perhaps from far away you could hear the melody but not the jet.

It occurs to me that a large bank of electric fans forcing air into a constricted channel may be able to get as much airflow as a jet engine. Jet engines produce a lot of power in a small volume and weight, but if you're building a giant organ you may not care about volume and weight. That said, apparently wind tunnels sometimes do use gas turbine engines, so they might really be the right tool for the super-organ as well.

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  • $\begingroup$ I think this is the best answer, in the sense that it directly addresses what the question most likely intended. That said, the wind-pipe, and more critically the "cutting edge" (labium), will be subject to about the same air-flow as the engine itself. Jet turbines are reasonably advanced engineering, and presumable minimize their vibrations (since that would be wasted energy and excess fatigue), while the labium would be actively inducing as much vibration as possible. I would expect even a design without any "moving parts" to fail from mechanical fatigue quickly. $\endgroup$ Nov 17, 2023 at 16:13
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This is a frame challenge answer.

Yes, in a way not half as spectacular as what you are thinking of.

Jet engines as used in aircraft usually have the ability to supply compressed air to the aircraft. This is called "bleed air." Bleed air is tapped from the compressor. Bleed air is used to start other engines and to drive the air conditioning packs (the first engine is started from bleed air provided by the APU or by ground systems).

If you ignore the air going out the back of the engine, and use the bleed air instead, you could use that air for wind instruments. The result would be like an old-fashioned Orchestrion, but with a jet engine providing the air to run it. The jet engine would also be providing a rather loud sound that might completely overpower the Orchestrion. But you can just label the jet engine as a "drone instrument" and call it good.

A good reason to use the bleed air instead of the air coming out the back is that the bleed air will be a lot cooler and your instrument(s) won't need to be as fireproof.

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I suggest a flute:

enter image description here

There is no particular reason why this wouldn't work, although since the fundamental frequency of a wind instrument is inversely proportional to its length you'd better be prepared for an experience more like being shaken by an earthquake than an actual audible tone. I'd advise building the flute out of reinforced concrete for the same reason. (Or scale the whole thing down to the size of a large organ pipe and get a potentially almost usable but extremely loud bass tone.) On the other hand, this design uses an unmodified jet engine, and is clearly obviously ridiculous (assuming that's a plus point).

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Others have noted practical concerns and rightly question what makes something a musical instrument. But with that said, let me introduce Survival Research Laboratory's "Flame Whistle" - "Comprised of 200 lb. thrust turbojet with a fuel afterburner and a large police whistle attached. Machine is stationary and the engine has been modified to work in conjunction with the whistle, primarily to generate sound. It also produces hot air and small bursts of low-lying flame with an average distance of five feet. The engine is shielded by 1/4 inch thick steel plates (heat shield), runs on diesel fuel. Made in 1996." ( From https://srl.org/machines/flamewhistle/ )

So, if a police whistle can be considered a musical instrument - the SRL team built a jet powered musical instrument.

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