If there are 2x internal DACs in the STM32F407XX MCUs, why does the STM32F407VG Discovery Board need an external DAC for audio applications?

[YChu.7]

I'm very new to the STM32, so sorry if this sounds stupid. As far as I could understand looking at the datasheets, the STM32F407XX has 2 DACs, but when embedded in the discovery board an external DAC (CS43L22) is used. Why is that?

[Uwe Bonnes]

The internal DAC is noisier, but probably has better DC accuracy.

[AvaTar]

The CS43L22 DAC has higher resolution + less noise, and the chip adds headphone/speaker amplifiers.