# Strong aliasing in 24 kHz mode
**URL:** https://qa.fmod.com/t/strong-aliasing-in-24-khz-mode/21582
**Category:** FMOD Engine
**Tags:** ios, android
**Created:** [May 5, 2024, 7:16pm UTC](https://qa.fmod.com/t/strong-aliasing-in-24-khz-mode/21582 "2024-05-05T19:16:35Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@Insidewaves](https://qa.fmod.com/u/Insidewaves)
#### Post date: [May 5, 2024, 7:16pm UTC](https://qa.fmod.com/t/strong-aliasing-in-24-khz-mode/21582/1 "2024-05-05T19:16:35Z")
Hi!
I have an unexplained resampling problem. With a system frequency of 24 kHz on iOS and Android, there is irreparable aliasing. The useful signal from 8 to 12 kHz is reflected in frequencies from 12 to 18 kHz. I have tried all the options for bank settings and system interpolation settings (starting with the obvious - building banks at 24 kHz and using higher quality formats and interpolation methods), and have not yet found a way to eliminate this sound defect.
Tell me, is this a known fmod problem, or is there a way to configure the engine at this frequency so that there is no aliasing?
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### Author:  [@jeff\_fmod](https://qa.fmod.com/u/jeff_fmod)
#### Post date: [May 12, 2024, 11:28pm UTC](https://qa.fmod.com/t/strong-aliasing-in-24-khz-mode/21582/2 "2024-05-12T23:28:19Z")
This isn’t really an FMOD problem as much as it is an inherent issue with data sampling. That said, we could probably add an anti-aliasing filter to deal with this problem on your behalf- I will suggest that to the Dev team.
For now however, you have two options to deal with aliasing:
1. Use a sample rate of 44.1khz on iOS and Android. This will slightly increase audio latency, but will resolve the aliasing. You can override the iOS and Android sample rate with a call to [`System::setSoftwareFormat`](https://fmod.com/docs/2.02/api/core-api-system.html#system_setsoftwareformat) in your game.
2. Add a 48dB lowpass filter at 12kHz on your master bus. You will lose a little bit of high end energy, but it should eliminate high-frequency aliasing
If you are targeting more than just mobile, you can also use [Platform Exclusion](https://fmod.com/docs/2.02/studio/glossary.html#platform-exclusion) to only include this filter on Mobile platforms.
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### Author:  [@Insidewaves](https://qa.fmod.com/u/Insidewaves)
#### Post date: [June 4, 2024, 10:47am UTC](https://qa.fmod.com/t/strong-aliasing-in-24-khz-mode/21582/3 "2024-06-04T10:47:14Z")
Thank you Jeff
1. Yes, but i’m looking for a solution for 24 kHz mode. I think 44.1 kHz is not needed, 36 kHz is enough to take these reflections out of the audible range. This is a last resort method in case I don’t find another solution.
2. I tried to solve the problem this way - the result is on the 3rd screenshot. It looks like it doesn’t help.
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### Author:  [@Insidewaves](https://qa.fmod.com/u/Insidewaves)
#### Post date: [June 4, 2024, 12:09pm UTC](https://qa.fmod.com/t/strong-aliasing-in-24-khz-mode/21582/4 "2024-06-04T12:09:53Z")
> [@jeff\_fmod](#):
>
> we could probably add an anti-aliasing filter to deal with this problem on your behalf- I will suggest that to the Dev team.
Thanks! Anti-aliasing filter would be useful. I think that would be the best solution.
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### Author:  [@jeff\_fmod](https://qa.fmod.com/u/jeff_fmod)
#### Post date: [July 2, 2024, 7:15am UTC](https://qa.fmod.com/t/strong-aliasing-in-24-khz-mode/21582/5 "2024-07-02T07:15:33Z")
After some discussion with the Dev team, they have asked me to follow-up on your results with use of the different interpolation methods, which should have given you better results.
Can you please confirm that you called [`System::setAdvancedSettings`](https://fmod.com/docs/2.02/api/core-api-system.html#system_setadvancedsettings) with an alternative [`FMOD_ADVANCEDSETTINGS::resamplerMethod`](https://fmod.com/docs/2.02/api/core-api-system.html#fmod_advancedsettings_resamplermethod) before you called [`System::init`](https://fmod.com/docs/2.02/api/core-api-system.html#system_init), and not after?
If you are finding that it doesn’t help at all, then can you please also tell me what version of the FMOD Engine you are using?
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### Author:  [@Insidewaves](https://qa.fmod.com/u/Insidewaves)
#### Post date: [July 2, 2024, 9:40am UTC](https://qa.fmod.com/t/strong-aliasing-in-24-khz-mode/21582/6 "2024-07-02T09:40:26Z")
> [@jeff\_fmod](#):
>
> Can you please confirm that you called [`System::setAdvancedSettings`](https://fmod.com/docs/2.02/api/core-api-system.html#system_setadvancedsettings) with an alternative [`FMOD_ADVANCEDSETTINGS::resamplerMethod`](https://fmod.com/docs/2.02/api/core-api-system.html#fmod_advancedsettings_resamplermethod) before you called [`System::init`](https://fmod.com/docs/2.02/api/core-api-system.html#system_init), and not after?
Yes
> [@jeff\_fmod](#):
>
> what version of the FMOD Engine you are using?
2.02.22