Passive Sound Modifier EQ affecting all audio - bug or feature?

Hi there,

I have a project in 4.7.6 that’s based on the ShooterGame template. But I added a new Sound Class called Radio. The Radio class uses a Passive Sound Mix Modifier that uses an EQ effect that mimics a radio - I need the effect to be applied in real-time. When I play any sound of type Radio, the EQ effect affects every sound in the game.

So then I realized that I probably need to assign which Sound Class is affected in the PSM. So I set the Sound Class in the PSM to Radio, thinking it would only affect sounds of the Radio type. But it still affects everything.

That seems like a bug to me, based on what it seems like it should do. The documentation is pretty sparse on this, so I’m just guessing at how it is supposed to work. If this is the intended behavior, then is there another way to get what I’m looking for?

Hey JigglyToes,

Take a look at the Documentation we have on Sound Classes and Passive Sound Modifiers. It goes over the questions you have about how they are supposed to be implemented and how they function with other sound classes as well.

Audio Overview

Let me know if this information clarified your questions or if need further assistance.

Thank you,

Thanks for the link - I have already read it, but details are sparse. It seems like there is conflicting information.

On the one hand, it says: “As the EQ Settings of multiple Sound Mixes cannot be combined…” and that makes me think that a Passive Sound Modifier’s EQ settings affect everything in the game, so you can’t have them affect only certain sounds.

But then in the next paragraph, it says: “Inside the Sound Classes section, you set which Sound Classes are to be affected by the mix.” - And that makes me think that I should be able to specify which sounds are affected.

So it’s still unclear to me if this is the intended behavior, or a bug.

"Multiple Sound Mixes can be active at the same time, all contributing to the overall audio effect. You can Push (Activate) or Pop (Deactivate) Sound Mixes directly inside a Blueprint with the Push Sound Mix Modifier and Pop Sound Mix Modifier nodes or activate them passively whenever a sound with a given Sound Class is playing within a specified threshold.

This means that you can activate the Passive Sound Mixes via Blueprints at the same time.

"As the EQ Settings of multiple Sound Mixes cannot be combined, the EQ Priority allows you to control which active mix’s properties are applied at any given time.

This means you cannot have multiple EQ settings overlapping. You can still play the sound mixes simultaneously, but you must set the priority of your EQ settings so they can be applied correctly relative to their Sound Class.

After some tests, it clearly sounds like the EQ is being applied to all sounds that have “Apply Effects” flagged in their Sound Class settings, whether or not that Sound Class was added to the Sound Mix asset. That definitely seems like a mistake. I can’t think of any scenario where I would want to apply EQ on a master buss, but I might be limited by practical demands and I’m just not being creative enough.

I understand that while multiple Sound Mixes can be active (or Popped. or is it Pushed? I can never remember which one is “activate” and which one is “deactivate”) at the same time, only one EQ can be active at a time. That’s reasonable and using the EQ Priority to handle that makes sense.

What’s not clear is why EQ would be applied to EVERY SOUND. EQ should be applied only to those Sound Classes in the Sound Mix with the active EQ setting.

On a side note, it’s also not clear how the volume and pitch adjustments are factored when multiple mixes are active. For instance, if I have a volume adjustment of 0.5 on a class in one mix and another volume adjustment on the same class of 0.5, would the sounds in that class be 0.0 or 0.25 (half, then half of that)?

Hey viktorphoenix,

I understand your concern and am going to run some tests today to verify what you are reporting. The EQ settings applied to your sounds should only be apparent to the sounds that are within the specified sound class. We are currently working on revamping our audio system along with the documentation associated with the functionality of the audio framework. I will return here with any new information that I find.


Thank you for looking into this, .

Hey again viktorphoenix,

Would you mind showing me how you have your Master Class child/parenting node set up as well as your EQ settings and where you are applying them?

I would like to run a comparison between your set up and my own.

Thank you,

Here’s a few screen captures. Master, SFX, Voice, and Music soundclasses are in Engine Content, the children are in the game content.

A new default soundmix recently went in that is making this hard to test and reconfirm on my end, but this is an example of one set up.

Let me know if and when you are able to repro and reconfirm the issue. I have been running tests on my end, and thus far have been unable to confirm what you are reporting. Thank you for the providing the requested information either way!


I went back to this and realized that there’s an easy answer to my original question: in the Sound Class, there’s a check box for “Apply Effects”. If I turn that off on everything except the class that I want the EQ effects on, it works properly. Luckily, there are no other sound classes that I want EQ effects on, so hopefully this is a decent solution for the time being.


I think I have encountered a related issue:

Here are repro steps for a potential bug:

  1. Create two Sound Classes, e.g. Music and SFX, each with Apply Effects enabled

  2. Create a Sound Mix with EQ enabled

  3. Assign SFX Sound Class to this Sound Mix in the Sound Classes section

  4. In level BP add Push Sound Mix Modifier function, assign the Sound Mix created in point 2 to it, and connect it to Begin Play

  5. Add two sounds to project (Sound A and B)

  6. Assign Music Sound Group to sound A and SFX Sound Group to sound B

  7. Add both sounds to the level, for example as Ambient Sounds

  8. Play

Current Result:
EQ is applied to both sounds.

Expected Result:
EQ should be applied only to sound B.

Basically the same thing happens when I try to use the Passive Sound Mix.