Before we start, sit back and relax, and let me have you a cup of context : Last month, While wandering on the netdom, I wondered how I'd add some cultural interest to my medieval fantasy kindom. As I was lost in thought (and among dog and cat pictures), I somehow stumbled upon the concept of thermoacoustics. In ultra-short, it is about relating sounds to temperature and vice-versa, by for instance making sounds through hot-to-cold airflows made from a precisely located source of heat.
As I looked into it, I thought to myself : "I have mages who are able to control fire magic. I like the concept of thermo-acoustics and I also like the sound of wind instruments... So why not use some of my fire magicians to make some heart-warming music?"
The issues I faced
As I delved deeper into this, some points have begun to worry me. Namely :
- Note control seems to be difficult. For instance, pyrophones (explosive fire organs) notes are highly dependent on the fuel intake and output. On this kind of model, you need a tube for every note you wish to play, heating each of them separately, which means more mechanism work. On another melody, if you keep a steady airflow like shown in science experiments you can find on the internet, you can't really tune up and down the volume, which is a key element to break the monotony of a music.
- Moreover, accurate note length is apparently hardish to get. Indeed, on the smaller, glass-tube experiments I saw, sounds is produced by the difference in air pressure, difference which is made by the temperature, heat which doesn't die down as fast as one's breath. Every flute holes could be plugged in, but doing it by hand seems impractical, and if you just move in a finger just a little out of time with the others, you could hear another quick, unwanted note slipping out. Alternatively, you might rotate the instrument to alter the air flow, but it's as cumbersome as it sounds, especially if you need to do it 10 or 20 times in a single song.
This all brings to my last key point :
- Ergonomy : This is the last, most bothering issue from my point of view. As shown above, controlling the notes sounds like it needs some tricks or complex gears to avoid being an hassle, but I wish my flute to be some sort of traveler's companion, ie. portable. The few heat-based instruments I saw didn't really fit that description (organs and pyrophones, some drums with lots of mechanisms behind...), but worse : I fear that the extended use of this instrument bring at least discomfort to your hands, since metal such as brass or iron are good heat transmitters, and wooden instruments are... Welly they're made from wood, and I doubt there's something to make them less flammable for extended use.
This all brings to the impending question :
How can I create a good-sounding portable fire flute?
Here's my goals regarding this instrument :
- Be portable and ergonomic enough.
- To have enough notes to play some melody. Not looking into making all possible notes, but something like a recorder with one or two less holes.
- To be able to vary the notes in terms of volume and length.
- To not harm or cause too much discomfort for the user on long-term use.
- I'd like something relatively small, which can be carried around during your travels. Ideally, think about clarinet, recorder or oboe for instance. Also, notice I'm more interested in small width than length.
- I don't need a particularly powerful instrument, the flute is intended to be played among small to medium attentive -and therefore quiet- audiences.
- If I can have flames coming out of it, that'd be sweet, but it's far, far less important.
About fire magic
The fire magic involved is relatively standard, but to be sure everyone is on the same page, here's what I have already set on this topic :
To create fire, the sorcerer needs to focus some magical energy from within themselves and throw it outward, resulting in the production of a flame. Magic in this case effectively replaces the fuel such as wax or wood in the fire triangle and give the initial heat impulse and spark to start it, too1. This means you still (but also only) need oxygen to sustain the fire through magic. It can be produced from any part of the body, though most magicians are used to produce it from either their fingers, the palm of their hands or for some their mouth and/or feet. You don't need any specific item such as crystals or relics to use magic.
Concerning power output and long-term focus, consider there's no limit to the amount of power range you can choose. Most mages have a fine control on the lower as well as higher temperature levels and area of effect, and unless you ask them to engulf several building in flames, they should be able to keep on long enough. There are however two limitations to take into account : Producing fire from a distance and doing so while moving relatively to it.
First, let's talk about producing fire from a distance. What do I mean by this? It's possible to throw long fans of flames over several meters, but it's really hard to make a torch lit up from afar without sending some heat between you and it. It's akin to the difference between moving a chair with your hands or with the tip of a stiff rope : Pushing with the rope is harder and need much, much more energy as the force is defused along it. However, it's still possible to throw fireballs and such : The technic there is to create the fire in proximity to the body and build some magic for it to feed on, then impulse it forward. Sort of like you molded a ball of wood, lit it then kicked it away before it extinguishes. In this case, some heat is sent on the way between you and your target, but in a short pulse compared to a fan of flames.
Second constraint, focusing your mind and body to create an accurate source of fire from a distance is harder if the point where the magic is flowing out is moving relatively to the target, especially in a non-linear way. If you try to fry a precise point inside a cylinder, it's easy if you grip your hand on it, harder if you slide it significantly along the tube -it's linear-, and much harder if you dance around while the tube is laying on the ground (not accounting energy loss from the distance).
To sum up, you can't reasonably produce a good concerto's length of music if you move your fire source (hand/mouth...) at more than about one finger away from the fire target, and you'd need a few years of fire magic experience if you need to slide your hand along the flute while keeping the target locked, and easily 5 to 10 years of continuous practice while moving non-linearly.
Finally, note that fire magic usually doesn't burn up its user : As long as the fire is sent outward from them, they are relatively well protected from it (they at most feel warmth). However, they are much less protected from heat going back to them or when it is accumulating in the environment. Instances of such backfiring can be burning air bouncing back from a wall close to them, or as heat is transmitted from the back of a cylinder to their fingers through thermal conduction. Keep heating up an iron bar you hold for 5 minutes and you'll surely get your day of blisters and burns.
Other world data and constraints
- Technology can be up to mid-18th century technology, excluding any modern energies such as gas, coal or electricity (if you'd ever use any).
- Material is only constrained by technology. If you want to make a flute out of pure gold, go for it (my fire mages have money to spend).
- The same goes for inner complexity. As long as the objects used don't break during travels or during long use, that is...
- Shape can be anything you can picture : saxophone, clarinet, oboe, pan flute, alien thingy... It's of course, limited by the size I told in the goals.
1 : Note it's possible to generate pure heat with my magic system without flames, but I believe it's exhausting enough to not be a viable option to play an instrument using solely pure heat generation.