What are the benefits of iPhone 6s having 2 audio chips?

After downloading my audio library from iPhone 4s to 6s (big step...) I realized that the quality of sound generated through bluetooth directly into an external Digital/Analog Converter (DAC) has improved substantially.

Since I am bypassing most of the iPhone 6s electronics (DAC, Amplifier, Speakers) I tried to investigate about the new circuitry of the 6s and all I found was that there are 2 x Cirrus Audio Chips but I cannot find anything written about the technology and added benefits of the new chips or why 2 chips are better than one (what is the function of each one).

All I found was articles about why Cirrus share price went up after the discovery of the 2 chips in the new iPhone, after teardown...

If anyone's got insights about the technology behind these chips and how do they improve the RAW audio signal (digital audio signal BEFORE DAC and before amplification), kindly share.

PS: the sound of the phone while talking has improved a lot, but I am not interested in the telephonic audio side of the device (better am

Thanks in advance. TP