I am new here and just at the beginning of a build (I'll share the details in a later topic). I'm brand new to all of this, so it's been a steep learning curve for me.

I'm running a B+ and I need to hook it up to a VGA monitor. So, I got an HDMI to VGA converter off of e-bay. This particular converter has an audio out connection on it to pull the audio from the HDMI.

When I hooked up the system video worked great, but I got no sound out of either the HDMI jack or the Pi's 3.5mm analog jack.
So I went into Raspi-Config and forced the audio out to HDMI, still nothing on there. Then I switched the speakers to the Pi's audio jack, forced the audio out there and I got sound! Success, I thought, but I had horrible static coming from the speakers along with the sound. I tried EVERYTHING to get the static to go away: changed speakers, changed power supplies, put a ferrite bead on the power supply and on the speakers, unplugged the Wifi dongle, key board, mouse and monitor. Still horrible sound.

In desperation, I hooked the system up to my HDMI TV and sound through there worked great. My TV also has a VGA connection, so I tried that. The video didn't work, but oddly enough the sound started working through the HDMI jack. This got me thinking that the Pi was sensing something and turning off the sound to the HDMI.

As it turns out, this is the case. If the Pi senses HDMI, it sends video and audio out the connection. If it senses DVI, then just video, no audio. For whatever reason, with the HDMI to VGA converter it was sending video and no audio.

A simple change in the config.txt as below (2) and clean sound came from the HDMI jack!! I still don't know why I get static with my sound out of the 3.5mm, but at least now I have a workable solution to get clean sound.

I hope this helps someone else!

hdmi_drive chooses between HDMI and DVI modes

hdmi_drive=1 Normal DVI mode (No sound)
hdmi_drive=2 Normal HDMI mode (Sound will be sent if supported and enabled)