# \[MacOSX\] 7.1 sound output on all channels

**URL:** <https://qa.fmod.com/t/macosx-7-1-sound-output-on-all-channels/19849>\
**Category:** FMOD Engine\
**Tags:** cpp\
**Created:** [February 8, 2023, 6:47am UTC](https://qa.fmod.com/t/macosx-7-1-sound-output-on-all-channels/19849 "2023-02-08T06:47:55Z")\
**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:** [February 8, 2023, 6:47am UTC](https://qa.fmod.com/t/macosx-7-1-sound-output-on-all-channels/19849/1 "2023-02-08T06:47:55Z")

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I am trying to create a player with FMOD-Engine using FMOD::System::playDSP. The System is configured for a 7.1 ChannelMap, for 7.1 SpeakerMode and 8 Speakers using setChannelFormat on the DSP.

But when I manipulate the buffer to send a stereo Signal to each port of the device (4 ports = 8 channels) I get a strange behavior.

The Front port (Front-Left & Front-Right) plays OK

The Back port (Back-Left & Back-Right) plays only the signal of its left channel

The Center / Bass port (Center & Lowfrequency) plays OK

The Surround port (Side-Left & Side-Right) plays nothing.

Also strange is, that if you set a MixLevelOutput on each channel with a value of 1.0f, the channel outputs and so the described behavior moves to a different port on the device like this:

Port Back output moves to port Center & Bass

Port Center & Bass output moves to port Surround

Port Surround output moves to Back.

I have already checked if the external USB Sound Device gets a signal on each of its channels via Audio Midi Setup on Mac. Also, I have tried to create Sound with pure CoreAudio API and this works also fine. I tried another software products that are not using FMOD and it also gives output to all output lines.

Is there anything else I could check?

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<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:** [February 9, 2023, 10:54pm UTC](https://qa.fmod.com/t/macosx-7-1-sound-output-on-all-channels/19849/2 "2023-02-09T22:54:03Z")

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H,

Something worth checking is what Speaker Mode ([FMOD API | Core API Reference](https://fmod.com/docs/2.02/api/core-api-common.html#fmod_speakermode)) the Core System is currently set to using [System:getSoftwareFormat()](https://fmod.com/docs/2.02/api/core-api-system.html#system_setsoftwareformat).

Hope this helps!