# Multiband EQ degrades audio on iOS

**URL:** <https://qa.fmod.com/t/multiband-eq-degrades-audio-on-ios/19592>\
**Category:** FMOD Engine\
**Tags:** ios\
**Created:** [November 28, 2022, 10:47pm UTC](https://qa.fmod.com/t/multiband-eq-degrades-audio-on-ios/19592 "2022-11-28T22:47:49Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![lukeabbottllc](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/lukeabbottllc/32/4155_2.png) [@lukeabbottllc](https://qa.fmod.com/u/lukeabbottllc)\
**Post date:** [November 28, 2022, 10:47pm UTC](https://qa.fmod.com/t/multiband-eq-degrades-audio-on-ios/19592/1 "2022-11-28T22:47:49Z")

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I added the multiband EQ DSP to some ChannelGroups in my FMOD-powered iOS music-generating app, but I noticed that the audio quality suffered when I did so.

The following audio files were captured with 0, 1, or 2 multiband EQs in the chain. No parameters were passed to these DSPs, so (I assume) they are totally flat.

No EQ in the chain:  
[https://www.dropbox.com/s/dwspit9r91y9eqo/Example%20with%200%20EQ%20DSPs.wav?dl=1](https://www.dropbox.com/s/dwspit9r91y9eqo/Example%20with%200%20EQ%20DSPs.wav?dl=1)

One EQ on the master ChannelGroup:  
[https://www.dropbox.com/s/9c9d4jywjnlz2fx/Example%20with%201%20EQ%20DSP.wav?dl=1](https://www.dropbox.com/s/9c9d4jywjnlz2fx/Example%20with%201%20EQ%20DSP.wav?dl=1)

Two EQs, one on the master ChannelGroup and another on one of the “buses”:  
[https://www.dropbox.com/s/s64ewv39ev77ds7/Example%20with%202%20EQ%20DSPs.wav?dl=1](https://www.dropbox.com/s/s64ewv39ev77ds7/Example%20with%202%20EQ%20DSPs.wav?dl=1)

[📥 Download all three files](https://www.dropbox.com/sh/fx2tcdtwuo1kgvk/AAD5WlXs9JA2aMUU110JYA0Ba?dl=1)

I tried the “Three EQ” DSP and it did not have this issue; quality was identical with or without that DSP on the chain. But I was hoping to use the multiband EQ…

Note, I have not tested this out on other platforms.

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<div class="post-metadata">

**Author:** ![mathew](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/mathew/32/431_2.png) [@mathew](https://qa.fmod.com/u/mathew)\
**Post date:** [November 29, 2022, 12:38am UTC](https://qa.fmod.com/t/multiband-eq-degrades-audio-on-ios/19592/2 "2022-11-29T00:38:40Z")

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Using the Core API, the default for a multiband EQ is for band A to be enabled and set to a 12dB lowpass with a cutoff of 8kHz and a Q of 0.707, all other bands are off. This is probably what you are hearing.

You can see the defaults for all DSPs in our docs, here are multiband [defaults](https://fmod.com/docs/2.02/api/core-api-common-dsp-effects.html#fmod_dsp_multiband_eq).

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<div class="post-metadata">

**Author:** ![lukeabbottllc](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/lukeabbottllc/32/4155_2.png) [@lukeabbottllc](https://qa.fmod.com/u/lukeabbottllc)\
**Post date:** [November 29, 2022, 4:00pm UTC](https://qa.fmod.com/t/multiband-eq-degrades-audio-on-ios/19592/3 "2022-11-29T16:00:24Z")

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Ah, I’m sure it is! What a peculiar design choice… anyway, now I know I can just override that band with my own settings. Thanks!