[alsa-devel] [PATCH] ASoC: nau8825: disable sinc filter for high THD of ADC

[John Hsu]

Hi,
On 12/5/2016 7:50 PM, Mark Brown wrote:
> On Fri, Dec 02, 2016 at 09:48:58AM +0800, John Hsu wrote:
>
>   
>> This bit will enable 4th order SINC filter.  
>> =1, filter will enable;  but it consumes higher power.
>> =0, the sinc filter is disable, and it should always keep 0 value to
>> get high THD.
>>     
>
>   
>> Therefor, disable the filter when codec initiation for better
>> performance when recording.
>>     
>
> This looks like something that users should be able to control at
> runtime - while some users are going to prefer lower power there will
> most likely also be some users who prefer the better performance (or
> perhaps even users who switch depending on if they're running on battery
> or something).
>   

The function is not suitable for the voice application and easy to
make distortion. Therefore, we want to disalbe it as default to
get a high signal to distortion ratio. Yes, I agree it that users
maybe want to eanble it sometimes. I can add a kcontrol for the
function as well.