# Way to measure loudness in 3D space

**URL:** <https://qa.fmod.com/t/way-to-measure-loudness-in-3d-space/19960>\
**Category:** FMOD Engine\
**Created:** [March 10, 2023, 2:16pm UTC](https://qa.fmod.com/t/way-to-measure-loudness-in-3d-space/19960 "2023-03-10T14:16:04Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Electromess](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/electromess/32/2794_2.png) [@Electromess](https://qa.fmod.com/u/Electromess)\
**Post date:** [March 10, 2023, 2:16pm UTC](https://qa.fmod.com/t/way-to-measure-loudness-in-3d-space/19960/1 "2023-03-10T14:16:05Z")

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Hi,

As I understand it, wherever you place the FMOD loudness meter plugin, in an Event, or a Group Bus output, It always measures relative to the Listener perspective. Is there a way to read LUFS values at a particular point in 3D space, independent of a Listener?

In our project, that aims to be not so much a game as a realistic simulation, we could really use a way for an NPC to become alert when a certain loudness threshold’s reached. Many factors could cause the sound to change, dampen or be occluded, on its way to the NPC.

Any thoughts or suggestions? Thank you.

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**Author:** ![Alcibiade](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/alcibiade/32/4284_2.png) [@Alcibiade](https://qa.fmod.com/u/Alcibiade)\
**Post date:** [March 11, 2023, 7:27pm UTC](https://qa.fmod.com/t/way-to-measure-loudness-in-3d-space/19960/2 "2023-03-11T19:27:53Z")

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Maybe by using a second (virtual) listener at the 3D location you want to measure?

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**Author:** ![Electromess](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/electromess/32/2794_2.png) [@Electromess](https://qa.fmod.com/u/Electromess)\
**Post date:** [March 11, 2023, 10:09pm UTC](https://qa.fmod.com/t/way-to-measure-loudness-in-3d-space/19960/3 "2023-03-11T22:09:01Z")

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Yes, that option did occur to us. The thing is, what if the number of measurements, each in a different location, went up to tens, or hundrends at any given time? There’s a limit to the total number of listeners, right? Also, wouldn’t it be a bit of an overkill performance-wise?

Is there perhaps a way to create some kind of simple virtual “microphone” channel, using the DSP system?

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**Author:** ![Connor\_FMOD](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/connor_fmod/32/3685_2.png) [@Connor\_FMOD](https://qa.fmod.com/u/Connor_FMOD)\
**Post date:** [March 20, 2023, 12:19am UTC](https://qa.fmod.com/t/way-to-measure-loudness-in-3d-space/19960/4 "2023-03-20T00:19:52Z")

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Hi,

Apologies for the delayed response.

> [@Electromess](#):
>
> There’s a limit to the total number of listeners, right?

Yes, the limit is 8 ([FMOD API | Core API Reference](https://fmod.com/docs/2.02/api/core-api-common.html#fmod_max_listeners)).

> [@Electromess](#):
>
> Also, wouldn’t it be a bit of an overkill performance-wise?

Yes, that is why we limit it to 8.

> [@Electromess](#):
>
> Is there perhaps a way to create some kind of simple virtual “microphone” channel, using the DSP system?

Unfortunately, this is not something we support. You would have to create your own DSP. We provide an example of creating your own DSP with the FMOD Engine here:

```auto
X:\Program Files (x86)\FMOD SoundSystem\FMOD Studio API Windows\api\core\examples

```

I would suggest using the Inverse Square Law when calculating the loudness, which is essentially that every doubling off distance equates to 6dB off attenuation, so if you are 1m from a sound source and it is 100dB, at 2m it will be 94dB and at 4m it will be 88dB. There are other factors such as occlusion and sound reflections, but you can approximate it pretty well using the Inverse Square Law.

Hope this helps!

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<div class="post-metadata">

**Author:** ![Electromess](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/electromess/32/2794_2.png) [@Electromess](https://qa.fmod.com/u/Electromess)\
**Post date:** [March 21, 2023, 12:45pm UTC](https://qa.fmod.com/t/way-to-measure-loudness-in-3d-space/19960/5 "2023-03-21T12:45:54Z")

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@Connor_FMOD  
Our project might not be using FMOD in the end (not because of this particular problem), but I still very much appreciate your answer. Thank you!