Wall of Force and Sound

[legomaster00156]

As we all know, very few things pass through a Wall of Force. Light passes through completely unhindered, as the wall is invisible, but it stops pretty much anything else, including sonic attacks. Does this also mean that a Wall of Force is soundproofed, or merely that it muffles or distorts sound?

[Crake]

if the wall is completely immovable, then yes, it would be completely sound proof, as it wouldn't be able to vibrate. Keep in mind however, that whatever objects the wall is meeting will continue to carry sound, so while the wall of force itself is completely sound proof, you would still hear muffled sounds through the walls/floor/ceiling. A solid forcecage on the other hand would be completely soundproof.

[legomaster00156]

Ok, and throwing on another question regarding the same spell, should not light-based effects ([light] spells, Brilliant Energy weapons, etc.) pass through a Wall of Force?

Edit: Ok, found the relevant text, though it doesn't seem to interfere with brilliant energy weapons.

Breath weapons and spells cannot pass through a wall of force in either direction...

[Psyren]

Air can pass through force effects just fine, so sounds should too. Resilient Sphere for example states that the subject can breathe normally. Forcecage is not as clear-cut, but for what it's worth, the Giant appears to agree (http://www.giantitp.com/comics/oots1104.html) with this interpretation..

With that said, sound != sonic attacks. Just because something lets sound through doesn't mean that sound-based attacks get to ignore it. I'm sure closing a door on a Sound Burst wouldn't render it completely inaudible for example, but by RAW it would keep the spread from harming anyone on the other side.

[SirNibbles]

http://www.giantitp.com/forums/showthread.php?524574-Can-air-pass-through-a-Wall-of-Force-or-a-(windowless)-Forcage

There was a discussion on a related topic that you might want to check out.


Air can pass through force effects just fine, so sounds should too. Resilient Sphere for example states that the subject can breathe normally. Forcecage is not as clear-cut, but for what it's worth, the Giant appears to agree (http://www.giantitp.com/comics/oots1104.html) with this interpretation..

With that said, sound != sonic attacks. Just because something lets sound through doesn't mean that sound-based attacks get to ignore it. I'm sure closing a door on a Sound Burst wouldn't render it completely inaudible for example, but by RAW it would keep the spread from harming anyone on the other side.

Considering Sound Burst is a spread effect, it might.

"A spread might still affect a creature that has total cover, if the spread’s area allows the effect to cover the distance." - Rules Compendium, page 39

It comes down to whether you think the wall of force has any gaps of any size.

I would like to add that the DC 120 Escape Artist check to pass through a Wall of Force doesn't necessarily mean there are holes in the wall- epic skill checks are often equivalent to magical abilities or (Ex) abilities (which can ignore the laws of physics).

[Doctor Awkward]

Here is my relevant post from the previous thread (linked above) regarding this question:

2. Sound is energy
Sound is acoustic energy, and as with any other form of energy, it cannot be destroyed: it can only converted to another form of energy. Sounds die away naturally because their vibrational energy is converted to (a very small amount of) heat, either due to friction in the air itself or in moving (vibrating) the objects it encounters. Sound also reduces in level the further it travels from the source, as its energy becomes spread over a larger area, something that is represented as the inverse square law, due to the fact that the sound intensity of an omnidirectional source reduces relative to the square of the distance from the source. More precisely, sound is vibrational energy in the audio frequency range that passes through the air, and can also be conducted via solids or liquids. Though airborne sound cannot escape directly from an airtight environment, its vibrational energy causes the structure of that environment to move and they in turn launch new soundwaves which can be heard outside. Incidentally, the sound isolation provided by a structure reduces with frequency. This is quite logical because it clearly takes more energy to make a wall vibrate back and forth a thousand times in one second than it does to make it vibrate back and forth say 20 times. It's a simple matter of inertia. For every octave drop in pitch the amount of sound isolation is roughly halved, so while high frequencies are easy to keep in or out, low frequencies are far more difficult to contain. This is why when you walk outside a night club you can still hear the bass and kick drum but little else.

In any case, as materials of infinite stiffness, such as is found in a Wall of Force, do not exist in real life, it is impossible to guess with any accuracy what would happen in such a situation. But one could hypothesize that if the wall cannot be affected by any form of energy, then it is likely exempt from the laws of physics, and thus any fully formed container of Force would be completely soundproof, preventing anything emanating from one side from being heard by anything on the opposite side. Of course, such a construct would also become a perfectly isolated system, exchanging neither matter nor energy with it's surrounding environment, and its contents would remain in the precisely the state it was when the barrier was created, perfectly insulated from the environment outside.

Practically? As the spell description does not indicate it interferes with how the occupant experiences the surrounding environment in any way, it is very likely neither watertight, airtight, nor soundproof. And if air can pass through a Forcecage, then so can sound.

[SirNibbles]

Practically? As the spell description does not indicate it interferes with how the occupant experiences the surrounding environment in any way, it is very likely neither watertight, airtight, nor soundproof. And if air can pass through a Forcecage, then so can sound.

Resilient Sphere does state that "Nothing can pass through the sphere, inside or out" (Player's Handbook, page 258). If it is the default property of a force surface to behave in the same manner as Resilient Sphere, it would stand to reason that nothing can pass through Wall of Force or Forcecage either. Of course, that's open to interpretation.

As sound must vibrate the medium through which it passes, if it cannot vibrate the Wall of Force—"The wall cannot move" (Player's Handbook, page 298)—and we assume no matter can pass through it, sound also would be unable to pass through.

[Psyren]

Considering Sound Burst is a spread effect, it might.

"A spread might still affect a creature that has total cover, if the spread’s area allows the effect to cover the distance." - Rules Compendium, page 39

It comes down to whether you think the wall of force has any gaps of any size.

Oh, certainly it could envelop a wall or a barred forcecage and get to the target behind it. But a windowless forcecage or a resilient sphere are a different matter.


Resilient Sphere does state that "Nothing can pass through the sphere, inside or out" (Player's Handbook, page 258). If it is the default property of a force surface to behave in the same manner as Resilient Sphere, it would stand to reason that nothing can pass through Wall of Force or Forcecage either. Of course, that's open to interpretation.

As sound must vibrate the medium through which it passes, if it cannot vibrate the Wall of Force—"The wall cannot move" (Player's Handbook, page 298)—and we assume no matter can pass through it, sound also would be unable to pass through.

Air must be able to pass through, because "the subject can breathe normally" (Player's Handbook, page 258). And if air can make it through, so can sound - vibrating the wall itself isn't necessary if the air can vibrate sound through.

[Elkad]

Air must be able to pass through, because "the subject can breathe normally" (Player's Handbook, page 258). And if air can make it through, so can sound - vibrating the wall itself isn't necessary if the air can vibrate sound through.

That doesn't follow.
If you remove most of the energy from the air that touches the wall, it could still filter through, but sound wouldn't. (at least not in a recognizable form)
If you teleport molecules of air from one side to the other, they aren't touching one another and can't transmit sound.
If the wall has a transmutation effect rider that keeps trying to restore the air inside to it's original mix, new air wouldn't need to get in at all.
Or myriad other ways involving magic.

[Psyren]

That doesn't follow.
If you remove most of the energy from the air that touches the wall, it could still filter through, but sound wouldn't. (at least not in a recognizable form)

So you're saying the air can move enough to pass through the barrier, but not enough to vibrate? What?



If you teleport molecules of air from one side to the other, they aren't touching one another and can't transmit sound.
If the wall has a transmutation effect rider that keeps trying to restore the air inside to it's original mix, new air wouldn't need to get in at all.
Or myriad other ways involving magic.

But the sphere says nothing about teleporting or conjuring air either.

Let's turn this around. Where does it say it blocks sound?

[SirNibbles]

Air must be able to pass through, because "the subject can breathe normally" (Player's Handbook, page 258). And if air can make it through, so can sound - vibrating the wall itself isn't necessary if the air can vibrate sound through.

I'll argue the same as I did two years ago: you can breathe normally because there is air inside the sphere, and in sufficient quantity to support breathing. That is to say, that spell has no effect on the rules regarding breathing: they are applied normally.

Reposting from the old thread:
There are rules for suffocation in enclosed spaces of a limited volume, as defined in Underdark, page 107.

"Any closed space that is reasonably airtight can quickly become stale or depleted. In general, a Medium creature depletes about 1,000 cubic feet of air (a 10-foot cube) every 6 hours. A Small creature requires one-half as much air, and a Large creature requires four times as much. Air becomes stale when it is halfway to depletion."

Stale air requires Fort saves vs fatigue (and eventually exhaustion). An exhausted character in stale air takes 1d6 nonlethal damage every 15 minutes.

Depleted air just makes you suffocate, dealing 1d6 damage every 15 minutes until you fall unconscious and then killing you 2 rounds later.

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My point is that breathing normally in a 'reasonably airtight' space means you eventually suffocate.

I accept that your interpretation is equally valid and is pretty much down to the DM.

[Psyren]

My point is that breathing normally in a 'reasonably airtight' space means you eventually suffocate.


I interpret "normally" to mean "as though the spell were not cast." Meaning if you're in an area where you would not suffocate without a resilient sphere, the spell doesn't change that.



I accept that your interpretation is equally valid and is pretty much down to the DM.

Ok.

[Elkad]

So you're saying the air can move enough to pass through the barrier, but not enough to vibrate? What?
Slow the vibrations down by 99%. Sound would become unrecognizable. But air would still permeate through enough to allow breathing.




But the sphere says nothing about teleporting or conjuring air either.

Let's turn this around. Where does it say it blocks sound?


Nothing can pass through the sphere, inside or out.

That pretty clearly blocks sound. And light. You can breathe normally because it only lasts minutes, and at minimum caster level, there is 180 cubic feet of air (minus your own volume, 2-5 cubic feet for medium), enough to last you for many hours before CO2 poisoning is an issue. Or if you follow the rules for suffocation instead of muggle science (so you get 6 hours in 1000 cubic feet), then you still get an hour.

Forcecage is different. It just references Wall of Force, and says it is invisible. So Gaze attacks (and light) would pass through. It (and wall of force) doesn't actually mention any other effect specifically. It blocks spells and creatures, but it doesn't mention blocking sound. But it doesn't mention blocking objects either, so I could just pelt you with rocks/arrows too.

So if I flood the room with Chlorine or Hydrogen, while you are safely inside a Forcecage, what happens? It gets in and poisons/suffocates you? You breathe normally anyway? You breathe normally until the air in your cell runs out, and then you die?
How about if I seal the doors and build a bunch of fires? (CO plus lack of O2)
What if you build a big fire inside the cage? Can you waste all your air quickly? Or does it replenish?

[Psyren]

That pretty clearly blocks sound.

I disagree that sound is a "thing" in that context. Is the sphere opaque? If not, light is clearly getting through it. Does telepathy/mindsight work? Blindsense/Blindsight/Tremorsense? Lifesense/Soulsight? Can you scry on someone inside? Will a detect magic or locate creature work on someone inside? Etc. So I don't think it's "clear" at all.

[Mato]

Air must be able to pass through, because "the subject can breathe normally" (Player's Handbook, page 258). And if air can make it through, so can sound - vibrating the wall itself isn't necessary if the air can vibrate sound through.:smallsigh:

Just because it's a "shimmering" [force] doesn't mean it creates an unmovable solid plane of force. Just like air doesn't actually have to pass through, that's just an assumption that contraindicates the very sentence you think says it does. It's just a magical spell meant to be used for defense and to break physics. Here, I think I can speak GitP's language if that will help: You can breath mustard gas normally and the rules don't say surviving happens. tl;dr: Bad example.

[Psyren]

Just because it's a "shimmering" [force] doesn't mean it creates an unmovable solid plane of force.

Correct, that's exactly what I'm saying.


Just like air doesn't actually have to pass through, that's just an assumption that contraindicates the very sentence you think says it does. It's just a magical spell meant to be used for defense and to break physics. Here, I think I can speak GitP's language if that will help: You can breath mustard gas normally and the rules don't say surviving happens. tl;dr: Bad example.

Usually the rules tell you if you're in an enclosed space that would cause suffocation though, e.g. Portable Hole and Bag of Holding. So while your reading isn't invalid, exactly, I don't think it's intended either - certainly not as intended as "this spell can't be used to suffocate things you'd rather just not fight.

[SirNibbles]

Usually the rules tell you if you're in an enclosed space that would cause suffocation though, e.g. Portable Hole and Bag of Holding. So while your reading isn't invalid, exactly, I don't think it's intended either - certainly not as intended as "this spell can't be used to suffocate things you'd rather just not fight.

Bag of Holding is 2x2x4 (16 cubic feet) and has 10 minutes of air. A 10x10x10 cube is 1000 cubic feet and has 6 hours (360 minutes) of air. The space that is 62.5x bigger has 36x more breathing time. It's not exactly 1:1 but it's reasonably close, especially if they just rounded up to the nearest 5 minute increment.

Like I said earlier, slow suffocation applies to any space that is 'reasonably airtight' even without being specifically called out, according to the rules from Underdark, page 107. Since 'reasonably airtight' isn't defined anywhere, it's up to the DM to make the call on what is or isn't.

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As for intended readings, I doubt it was intended to let a fish breathe if it's out of water just because it's in a Resilient Sphere.

[Endarire]

I've run wall of force and forcecage as being totally solid and soundproof. No air passes through them.