Substitute for SSM2160 or SSM2163 (Audio Mixer ICs)

Hi all. The SSM2160 and SSM2163 seem to be well out of production. I've googled endlessly to try and find a chip that has the same function as either of these but I'm drawing a blank.

Does anyone have any ideas of a suitable replacement for these?

Refereces

SSM2160

SSM2163

Thanks, Rob.