# Is it possible to create a FMOD Echo effect with a EQ that only affects the audio copies?

**URL:** <https://qa.fmod.com/t/is-it-possible-to-create-a-fmod-echo-effect-with-a-eq-that-only-affects-the-audio-copies/22706>\
**Category:** FMOD Engine\
**Tags:** unity\
**Created:** [March 19, 2025, 12:49am UTC](https://qa.fmod.com/t/is-it-possible-to-create-a-fmod-echo-effect-with-a-eq-that-only-affects-the-audio-copies/22706 "2025-03-19T00:49:33Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![samuelmar](https://avatars.discourse-cdn.com/v4/letter/s/ba9def/32.png) [@samuelmar](https://qa.fmod.com/u/samuelmar)\
**Post date:** [March 19, 2025, 12:49am UTC](https://qa.fmod.com/t/is-it-possible-to-create-a-fmod-echo-effect-with-a-eq-that-only-affects-the-audio-copies/22706/1 "2025-03-19T00:49:33Z")

</div>

Hi,

I’m applying in Unity (on runtime) a FMOD.Echo effect to a specific track of a specific event, I’m doing the things this way.

```auto

FMOD.Studio.EventInstance myEventInstance = new FMOD.Studio.EventInstance();
        int _trackIndex = 1;
        //some no relevant code here...
        FMODUnity.RuntimeManager.CoreSystem.createDSPByType(FMOD.DSP_TYPE.ECHO, out FMOD.DSP delay_FmodDSP);
        delay_FmodDSP.setParameterFloat((int)FMOD.DSP_ECHO.WETLEVEL, -40.0f);
        delay_FmodDSP.setParameterFloat((int)FMOD.DSP_ECHO.DELAY, 500.0f);
        delay_FmodDSP.setActive(true);
        myEventInstance.getChannelGroup(out FMOD.ChannelGroup channelGroup_Master);
        channelGroup_Master.getGroup(0, out FMOD.ChannelGroup channelGroup_Track);
        channelGroup_Track.addDSP(_trackIndex, delay_FmodDSP);

```

It works well, but now I want to ad a EQ effect ONLY ON THE WET SIGNAL, I’m applying the EQ effect signal like this, but it is affecting both, WET and DRY signal/

```auto
FMODUnity.RuntimeManager.CoreSystem.createDSPByType(FMOD.DSP_TYPE.MULTIBAND_EQ, out FMOD.DSP delay_FmodDSP);
        delay_FmodDSP.setParameterInt(((int)FMOD.DSP_MULTIBAND_EQ.A_FILTER), (int)FMOD.DSP_MULTIBAND_EQ_FILTER_TYPE.HIGHPASS_24DB);
        delay_FmodDSP.setParameterFloat(((int)FMOD.DSP_MULTIBAND_EQ.A_FREQUENCY), 5_000.0f);
        delay_FmodDSP.setParameterInt(((int)FMOD.DSP_MULTIBAND_EQ.B_FILTER), (int)FMOD.DSP_MULTIBAND_EQ_FILTER_TYPE.LOWPASS_24DB);
        delay_FmodDSP.setParameterFloat(((int)FMOD.DSP_MULTIBAND_EQ.B_FREQUENCY), 2_000.0f);
        delay_FmodDSP.setActive(true);
        myEventInstance.getChannelGroup(out FMOD.ChannelGroup channelGroup_Master);
        channelGroup_Master.getGroup(0, out FMOD.ChannelGroup channelGroup_Track);
        channelGroup_Track.addDSP(_trackIndex, delay_FmodDSP);

```

What can I do to solve this issue? thanks in advance FMOD guys!

---

<div class="post-metadata">

**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 24, 2025, 4:00am UTC](https://qa.fmod.com/t/is-it-possible-to-create-a-fmod-echo-effect-with-a-eq-that-only-affects-the-audio-copies/22706/2 "2025-03-24T04:00:33Z")

</div>

Hi,

Thank you for the code. Could I please grab your FMOD integration version?

An option may be using [FMOD Engine | Core API Reference - DSP::addInput](https://fmod.com/docs/2.02/api/core-api-dsp.html#dsp_addinput) to divert the signal to a new chain where we can remove the dry signal and only pass the wet signal to the EQ:

 ![dspnet_capture](https://canada1.discourse-cdn.com/flex036/uploads/fmod/original/2X/a/add408c3920e22da4a39373e62acbd512c08c13e.png)  
(This image was captured using the FMOD Core profiler which is included with the FMOD Studio install)

```auto
// I am returing the effected signal to the final fader, but this can be any point you want
FMODUnity.RuntimeManager.CoreSystem.getMasterChannelGroup(out FMOD.ChannelGroup mcg);
mcg.getDSP(FMOD.CHANNELCONTROL_DSP_INDEX.FADER, out FMOD.DSP masterFader);

myEventInstance.getChannelGroup(out FMOD.ChannelGroup channelGroup_Master);
channelGroup_Master.getDSP(FMOD.CHANNELCONTROL_DSP_INDEX.FADER, out FMOD.DSP channelFader);

delay_FmodDSP.addInput(channelFader);
// I noticed you are using the same DSP twice, I am just using a new DSP for the EQ
// FMODUnity.RuntimeManager.CoreSystem.createDSPByType(FMOD.DSP_TYPE.MULTIBAND_EQ, out EQ_FmodDSP)
EQ_FmodDSP.addInput(delay_FmodDSP);
masterFader.addInput(EQ_FmodDSP);

```

I would also suggest adding `FMOD_RESULT` checks to your FMOD functions to aid in debugging:

```auto
FMOD_RESULT result = masterFader.addInput(EQ_FmodDSP);
if (result != FMOD_OK)
{
    //FMOD function failed so could add a debug log or run other code
}

```

[FMOD Engine | Core API Reference - Common](https://fmod.com/docs/2.02/api/core-api-common.html#fmod_result)  
I hope this helps!

---

<div class="post-metadata">

**Author:** ![samuelmar](https://avatars.discourse-cdn.com/v4/letter/s/ba9def/32.png) [@samuelmar](https://qa.fmod.com/u/samuelmar)\
**Post date:** [March 27, 2025, 4:26am UTC](https://qa.fmod.com/t/is-it-possible-to-create-a-fmod-echo-effect-with-a-eq-that-only-affects-the-audio-copies/22706/3 "2025-03-27T04:26:37Z")

</div>

Thank you so much Connor!

You provided me a very clear explanation. My FMOD version is Version: 2.02.20.

I’m attempting right now your suggestions in my project, if still have issues I’ll let you know.

Best Regards!