I think we're going to fence here a bit. Bare with me...
HDMI is just the same as the audio and DVI going down one cable trunk. That means you can use an HDMI cable, plug it into a monitor with speakers, and both video and sound comes through it.
Do not be confused: A GPU will never be Audio only as that's what a sound card is for. It's a Graphics processor 1st and will allow audio to go through (or around) it to conjoin it in the output (HDMI). But it IS possible to utilize the go through/around of the GPU's HDMI output to feed sound and then use the video card's other allowable outputs for video.
Is that the best? Who knows? So far we're just debating possibilities? What are you working with, what are you aiming for, and what are your means? I'm only guessing HDMI would better suit you for sound and can live with DP/DVI/VGA for Video. I know it sounds complicated, but if you just ask what you want, you can get a lot of help around here with many more options than the "standard".