DA7218 ALC erratic behavior

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cpeng03d
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DA7218 ALC erratic behavior

Hi dialog:

I have been experimenting DA7218 ALC features on the  eval board with Canvas. So far there are some erratic behaviors I could not reason with.

I used a tone generator as a source.

If the input to eval board is audio jacks, ALC behaves fine.

If the input to eval board is real sound from a speaker captured through the LP mic, ALC has a weird behavior describes as follows:

 

min set to -15dBfs, max set to -5dBfs, using hybrid mode. 

when noise level is set below -67dBfs, ALC behaves fine

when nose level is set > around 60dBfs, ALC fails to function! I turned up and down the volumn, no auto adjustment on the level as observed previously.

What's going on? Why a slightly higher noise level cripples ALC?

 

Device: 
ED_Dialog
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Hi,

Hi,

Let me look into this and get back to you.

Kind regards,

ED

ED_Dialog
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Hello,

Hello,

Do you have anti clip enabled?

Could you share you set-up script?

Kind regards,
ED

cpeng03d
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No the anti-clip ctrl is not

No the anti-clip ctrl is not enabled.

Here are my set-up script:

ALC noise set to -42 dBfs, ALC stopes working below the min threshold.

If you have it set to -67dBfs and lower, it will work.

Please take a look. Thanks.

 

ED_Dialog
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Thanks!

Thanks!

We would recomend enabling Anti-Clip. Do you calibrate the ALC?