Pulse Audio automatically switches audio output to HDMI when an HDMI connection is established.
A great tool you can use to overcome the various pitfalls of Pulse Audio is alsamixer.
Just to make sure it's installed, go ahead and run the following command:
sudo apt-get install alsa-utils
Then, connect the HDMI connection with the connection set to DVI-HDMI.
Next, run the following command in a terminal:
alsamixer
and then press F5 to view all channels.
You should see multiple channels. If you see only one channel for pulseaudio, you may need to press F6 to select a different card. However, if you do see multiple channels after pressing F5, continue.
Use the arrow key to scroll to the right and press the up arrow key to toggle the automute option to switch it off.
Now, there are two possibilities here.
First:
I think HDMI audio and analog audio are handled by two separate sound cards so you should have the option to select the analog stereo out sound card by pressing F6.
You should see something similar to the following example. This example shows only one analog output card. Should you have an extra digital card listed, switch to the analog card instead (HDA Intel PCH is a very common card for analog output).
┌───── Sound Card ──────┐
│- (default) │
│0 HDA Intel PCH │
│ enter device name...│
└───────────────────────┘
Alternatively:
When using the standard 1/8th in. (3.5mm for you metric people) stereo headphone jack for audio, this channel automatically goes to 0 when you switch to another out such as, built in speakers or HDMI. If this is the case, you simply need to go to the headphone channel and raise the volume using the arrow up key. Some desktop computers have multiple channels for front back, etc. Locate the correct output channel and raise the volume.
Another possibility is that the channel may be muted. If a channel is muted, it will say MM at the base of the indicator for that channel.
In any case and whatever channel it is, headphone out or not, select the channel using the right or left arrow key.
Then, press the M key to toggle mute off or on. Be careful here to have the volume at a safe level so that unmuting the device will not blow your speakers!!
Here is an example showing three muted channels:
┌──────────────────────────────────────────────────────── AlsaMixer v1.0.28 ─────────────────────────────────────────────────────────┐
│ Card: HDA Intel PCH F1: Help │
│ Chip: Conexant CX20590 F2: System information │
│ View: F3:[Playback] F4: Capture F5: All F6: Select sound card │
│ Item: Speaker [dB gain: -4.00, -4.00] Esc: Exit │
│ │
│ ┌──┐ ┌──┐ ┌──┐ ┌──┐ ┌──┐ ┌──┐ ┌──┐ │
│ │ │ │ │ │ │ │▒▒│ │ │ │ │ │▒▒│ │
│ │ │ │ │ │ │ │▒▒│ │ │ │ │ │▒▒│ │
│ │ │ │ │ │ │ │▒▒│ │ │ │ │ │▒▒│ │
│ │ │ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │ │ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │ │ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │ │ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │▒▒│ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │▒▒│ │▒▒│ │
│ ├──┤ ├──┤ ├──┤ └──┘ └──┘ ├──┤ Disabled └──┘ │
│ │MM│ │MM│ │MM│ │OO│ │
│ └──┘ └──┘ └──┘ └──┘ │
│ 61 85<>85 85<>85 99<>99 0<>0 9 100<>100 │
│ Master Headphone < Speaker > PCM Mic Boost Beep Auto-Mute Mode Internal Mic Bo │
│ │
└────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
When the channel is not muted, it should say OO instead of MM like in this example:
┌──────────────────────────────────────────────────────── AlsaMixer v1.0.28 ─────────────────────────────────────────────────────────┐
│ Card: HDA Intel PCH F1: Help │
│ Chip: Conexant CX20590 F2: System information │
│ View: F3:[Playback] F4: Capture F5: All F6: Select sound card │
│ Item: Speaker [dB gain: 0.00, 0.00] Esc: Exit │
│ │
│ ┌──┐ ┌──┐ ┌──┐ ┌──┐ ┌──┐ ┌──┐ ┌──┐ │
│ │ │ │ │ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │ │ │ │ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │ │ │ │ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │ │ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │ │ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │ │ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │ │ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │ │ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │▒▒│ │▒▒│ │
│ │▒▒│ │▒▒│ │▒▒│ │▒▒│ │ │ │▒▒│ │▒▒│ │
│ ├──┤ ├──┤ ├──┤ └──┘ └──┘ ├──┤ Disabled └──┘ │
│ │OO│ │OO│ │OO│ │OO│ │
│ └──┘ └──┘ └──┘ └──┘ │
│ 61 85<>85 100<>100 99<>99 0<>0 9 100<>100 │
│ Master Headphone < Speaker > PCM Mic Boost Beep Auto-Mute Mode Internal Mic Bo │
│ │
└────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
aplay -l.