How do I creat my double precision filter?

Hello,

I am working on a audio project with ADAU1701, that need adjust filter parameters at runtime, and my parameters is calculated by ADAU1701 itself, so I cann't use double precision IIR filter provided by sigmastudio, I must creat a IIR filter with multiply and add module by myself,

it seem that the calcutate result of multiply or add is signal precision, then how do I creat my double precision filter?

thanks!

cadie

Audio Signal Processors

SigmaDSP Audio Processors

adau1701