Wrong behavior of Attenuation Log Reverse ?

Hi everyone,

I’m stumbling upon a strange behavior of the Log reverse attenuation for sound cues. I linked an image with the actual problem.

I’m working on 3rd person weapons sounds. So based on the different curves i thought that log reverse would be the best. But the result is ( i’m starting from the outer radius when the players walks toward the sound source) :

  • At the end of the fall off distance, i’ve got an extremely high volume, even louder than the volume at the original location
  • At the start of the fall off distance, i’ve got a pretty low volume
  • From then end of the fall off distance to the start of the falloff distance, i’ve got the volume fading out from high to low. (A)
  • From the start of the fall off distance to the center of the location where the sound is played i’ve got the volume fading in from low to high. (B)

I’m pretty sure after listening a tons of times that the curve is in fact a log reverse in both cases (A and B)… but i don’t understand why the attenuation behaves like this.

Additionnal tests :

  • I created two projects from scratch, i still have the same result
  • I created a level without reverb volume, still the same result
  • I have disabled the falloff distance, the curve doesn’t seem to apply anymore, so the result is that the sound plays at maximum level as soon as the player enters the radius of the sound cue.

I didn’t put that in “bug reports” since i’m not sure if it’s a bug or if i am misunderstanding how i have to use this curve or attenuations in general.

If you have any idea about that issue, i would be really helpfull.
Thanks in advance.

Hello Olivier,

This is actually functioning as intended. If you want a sound be be sharp and concise when approaching it, regular Logarithmic is what you are looking for. Inverse means exactly what you are hearing. The sound will be lound the further away you get until you exit the fall off line, or when you come closer to the source.

Here is some helpful documentation on how to use sounds for certain scenarios, and how they look on a curve editor.

Audio Attenuation Documentation

I hope this helps shed light on your general audio a bit.


Hi Andrew,

Thanks for the answer ! I’m a bit late, but i got a ton or work.

So, i think i’ve understand pretty well what you are saying. But, the behavior i have doesn’t seem to fit what you’re explaining. The sound stays loud pretty much all the time when the player go further, but it suddenly goes loud again when he is entering the falloff. I made two additionnal pictures to show you “what curve” i hear.

If you want also, i can make a video.

The first picture shows the exact issue i’m having. If the player is between the source of the sound and the main radius, the sound behave just like you said. But if he is between the radius and the falloff distance, the curve seems to reverse. So if he exits the falloff, he has a really loud sound, then it suddenly shuts off.

Before i made my original post, i tried to remove the falloff. The second picture shows how the sound behaves again. The sound seems to fade a little from the source to the radius set in the settings, and then suddenly disappear when the player is out of it.

The studio i’m working with has the “rendering” issue, and a friend working with the engine too.

I used the documentation you linked at start. And i chose log reverse because it is specified underneath “Use case: Useful as a layer in weapons”… so maybe i’m missing something :slight_smile:

Indeed I think there’s something wrong with the model in AttenuationEval().

Here is the curve I have for a logarithmic attenuation, setting the fallof to an arbitrary 10. That’s the intended behaviour.

And here is what I get with the LogReverse one.

Hello again Olivier,

The way you implement this type of sound is not similar to the way you would implement the others pertaining to the sound radius. Since it is louder the further you get from the sound, keep the “Radius” to a ‘tight’ low value, and increase the fall-off to the area you would like it to attenuate. That way you will not hear the popping from the “Radius” itself when getting closer.

If you are trying to use sound for a weapon, I like to use the “Natural Sound” or “Linear.”

As mentioned previously, the LogReverse is working as intended, just the way you implement it is a bit different than other sounds.

I hope this helps,

Allright, i understand now. Maybe it should actually be written in the documentation.

I actually know what is a log and the reverse of it… but i’m pretty sure that everybody (just like i did) think that it is not gonna behave like this in engine… because i don’t see any real life cases where the sound is louder away from the source that it is near from it.

I don’t really know what i could do with that ingame … ( UE4 - Audio Source Log Reverse Attenuation - YouTube ) :smiley:

Anyway ! Thanks for you answers and your time Andrew.

You are quite welcome. I will let you know if I get any more information on the sound attenuation settings more specifically LogReverse. Best of luck!