Can PCs cause thunder damage or a related condition with simple purpose-built non-magic items?

Question

I would like one of my player characters (I am the player, and I will collaborate with my DM on this) in D&D 5e to craft (or possibly buy) a device that is intended to cause damage or a harmful condition by using sound. Almost a musical instrument, but designed specifically to be used as a weapon and not to sound pleasant. I can imagine something like this being crafted relatively simply, with wood, string, and maybe glue.

This answer suggests that a non-magical bomb could cause sonic damage, but a bomb is more destructive and not the style of craft that I would like.

The answers on this question include some alternatives to spells for causing thunder damage, but the items and abilities mentioned are still magical or divine, which I would prefer to avoid.

The item is intended to be able to be used by non-magical characters. In terms of flavor I was initially thinking of something small, shrill and high pitched, like a whistle or a clarinet mouthpiece, but something percussive might work as well. My PC would like to hurt his enemy's ears, or deafen them, or surprise them, in relatively close combat.

I haven't been able to find any specific non-magical items that cause thunder damage. Could I craft them? What might be the price for an item like this? Is thunder damage specifically magical in a way that would rule out a non-magical thunder damage weapon?

Answers that point to how this might work mechanically/in a balanced way are helpful to me.

Answer 1

Up to the DM, talk with them

I have to admit, I am mostly posting this to suggest it could look something like this:

This is the Gaffophone, also known as the Brontosaurophone, invented by Gaston Lagaffe, hero of an eponymous comic strip created by André Franquin and source of widespread mayhem and destruction, capable of damage to buildings. It has even been rebuilt in real life.

All of the following are just suggestions, as there are no written rules for this, so it is up to your DM.

Sonic Siege Weapon

You can work with your DM (if they agree to play along) to determine the game mechanics, and how to create an instrument like this, or if it can be bought. If you wanted to craft yourself, you probably would need some appropriate proficiency, like Woodcarver's tools, or Leatherworker's tools, and you said you'd like to avoid needing to be skilled, so you would need to commission it.

Looking at the benchmark of other non-magical special damage sources like alchemists fire or acid vial, damage for a large weapon-instrument like this should probably be in the low d4s or d6s. As this is sonic damage, area damage would be appropriate. The instrument would be Large and hard to move, similar to a ballista, and with shorter range hard to exploit for tactical advantage, so it should not be unbalanced to have this do a cone or radius area effect, maybe 2d6 in 10 foot, 1d6 in 20 foot range for cone, or the same in d4 for radius. For cost, the DMG does unfortunately not provide prices for larger weapons like siege equipment. I'd probably price it around 250 gp like a chariot.

Sonic Portable Weapon

Thunder damage is not inherently magical, only things caused by magic items, spells, spell slots or that explicitly say so are magical.

However, if you are looking for something practical, it is hard so see how something non-magical in a medieval world that is small enough to carry along would be able to generate enough sonic energy to harm or damage.

Pathfinder did have a magical item that was called a Thunderstone, you could throw it and upon hit it would trigger a 10-foot radius noise that called for the equivalent of a Constitution saving throw to not be deafened. Looking at basic poison, maybe a DC 10 and a duration of one minute with re-saves might be appropriate in 5e. But if you go this route, reskinning as DanB's answer suggests is likely the best solution. Such generic consumable magic items would not require you to be a spellcasting class to be able to use them.

Answer 2

There are no rules that would allow this, but you can reskin existing items

The obvious choice for what item to reskin would be the "acid vial" which costs 25gp and deals 2d6 acid damage on a ranged attack. You could rename it to "alchemical thunderstone" and have it deal 2d6 thunder damage instead, and it would be just as balanced as previously. (More specifically it would be sort of a waste of an action, since most characters can deal more than 2d6 with a normal attack.)

You could instead try reskinning the "alchemist's fire," but that one causes damage over time, so it's a less-good fit for the effect you want.

Note that magic-using characters will prefer to use a scroll of thunderwave, which is on many classes' spell lists and (probably) costs the same 25gp.

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You've indicated that you're looking for something reuseable.

The obvious option would be to reskin the flametongue sword to deal 2d6 sonic damage (instead of 2d6 fire damage). This is a rare magic item.

If that doesn't work for you, you could consider reskinning an uncommon magic item such as the circlet of blasting or the wand of magic missile.

You've told us that you want the item to not be magical, but that's as simple as just saying "this item isn't magical" and then narrating how it works.

Handing out magic items is very campaign-dependent. We can't tell you what a magic item should cost in your campaign, or whether it should be possible to find it at all. You will have to ask your DM.