Im fixing a friends DV6748us for this issue. Every forum Ive seen or post on this topic suggests installing a driver or not finding the right driver and I finally find an HP support person that posts the "solution" which turns out to be telling me to start the windows audio service? Really?
Here is what Ive gathered so far: There is a number of people having this issue with this model series made by HP, there is no audio device (hardware) being detected by windows because it doesnt show in the device manager, installing a driver only allows windows to utilize hardware but if there is no hardware then a driver doesnt do anything, I did a tear down on this pc and found there is a seperate audio card in the front of the pc where the headphone port is but there has to be some other component for audio where the power button is because this is where the speakers output.
When you see multiple people having this same issue a person is inclined not to think its failed hardware but at this point Im starting to think that HP has a defective issue with the way this pc was designed, the part(s) that they use, or the speakers installed.