I'm afraid you won't see a lot of information in this section anymore, mainly because since the last portable invention, audio has silently shifted to the software side. In other words, there are no longer dedicated audio chips.
You see, while the need for better graphics tends to grow exponentially (consumers want more scenery, better detail and colours), you won't hear the same level of demands for sound. I presume this is because the capabilities have reached our cognitive limit (44.1 kHz sampling rate and 16-bit resolution). The only thing left is to implement more channels and effects, but these don't need the processing power that would require installing specialised chips, at least with consumer equipment.
Summary of the audio pipeline.
So, in the end, audio is now completely implemented with software and processed by the SPUs (I mean the Synergistic Processor Unit, not the Sound Processing Unit! It's a bit ironic that both share the same initials...). Moving on, Sony provides many libraries in their SDK that instruct the SPUs to carry out audio sequencing, mixing and streaming. And if that's not enough, many effects can also be applied.
That being said, where is the audio signal sent for broadcast? The RSX. This chip also contains the ports used to broadcast raw audio signals to the TV. Before sending it, the signal is encoded in different formats, depending on the output selected (analogue, HDMI or S/PDIF, the latter is also called 'digital audio').