# playDSP plays only monophonic?

**URL:** <https://qa.fmod.com/t/playdsp-plays-only-monophonic/19562>\
**Category:** FMOD Engine\
**Created:** [November 22, 2022, 4:34pm UTC](https://qa.fmod.com/t/playdsp-plays-only-monophonic/19562 "2022-11-22T16:34:31Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![lemart1](https://avatars.discourse-cdn.com/v4/letter/l/3e96dc/32.png) [@lemart1](https://qa.fmod.com/u/lemart1)\
**Post date:** [November 22, 2022, 4:34pm UTC](https://qa.fmod.com/t/playdsp-plays-only-monophonic/19562/1 "2022-11-22T16:34:31Z")

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I have a custom DSP that I play with playDSP that is fed by a custom wave reader from a 16 bit stereo file. For some reason it is always playing it mono, means I hear the same sound on the left and right side and not as expected a stereo experience. Does anyone have an idea why this happened?

In FmodEx there was the channels option that is now entirely gone.

old FMODEx code:

```auto
FMOD_DSP_DESCRIPTION dsp_desc;
memset( &dsp_desc, 0x0, sizeof(dsp_desc) );
dsp_desc.channels = 2;
strncpy(dsp_desc.name, "Player", 32);
dsp_desc.version = 1;
dsp_desc.read = &DSPReadCallback;

```

---

<div class="post-metadata">

**Author:** ![Leah\_FMOD](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/leah_fmod/32/3685_2.png) [@Leah\_FMOD](https://qa.fmod.com/u/Leah_FMOD)\
**Post date:** [November 28, 2022, 12:09am UTC](https://qa.fmod.com/t/playdsp-plays-only-monophonic/19562/2 "2022-11-28T00:09:57Z")

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You may be looking for [`DSP::setChannelFormat`](https://www.fmod.com/docs/2.02/api/core-api-dsp.html#dsp_setchannelformat), which lets you set both the number of channels the DSP will receive with `numchannels`, as well as the mapping of those channels (i.e. Stereo) with `source_speakermode`.

Hope that helps!