Computer - projector - No sound when connecting with an HDMI cable

Hello.

I indicate in advance that I am not an IT specialist.

I have a computer connected (in the workplace) to a projector that has a built-in loudspeaker.

The connection method is HDMI.
The picture is but there is no sound.

For 2 days I've been trying hard to get what I need to do to make it work.
In the sound settings after changing the default device, nothing happens to it connected via HDMI.
Generally, it shows that the device is working properly. (only you still can not hear anything)
The volume of the device is set to ful, in the comp. Also.
The operating system is windows 7
I do not know what sound card (I'm writing a request for help from home)
The cable is OK - because it was checked during assembly on the laptop (there was no computer at the time).
When I try to update drivers it pops up the command that they are up to date.
The easiest way would be to call for IT but unfortunately before the employer does it, I will manage to make it.
Someone wrote about the SPDiF Audio cable but I do not know what's going on. (where would I check if it is missing? - I can not open my computer myself)

I will be grateful for the tips.
Magda

The spdif cable is an additional cable that can be used. However, if you do not have any sound, go to the sound settings, playback devices and check what you have available and set as default, it may be necessary to force the HDMI receiver to be the default sound device (after unplugging it should automatically change).

And you have graphic punishment connected to music?

Hello.
If I change the sound settings on the loudspeakers, it is OK - you can hear them in the speakers built into the monitor.

If the default device is a device connected to HDMI (as in the picture, unfortunately there is nothing). Although a green bar appears during playback.

The same situation is with the last item from the attached photo.
Do I have a connected music card for graphics - I do not know - I think that if the speakers work on the monitor, I think that's the way it works.

The best thing is that at home I have a similar connection to a computer and everything is ok. Well, maybe I only have a different operating system.
The computer with which I have a problem is school equipment.
It annoys me that I can not take full advantage of its capabilities (or more accurately the projector's capabilities)

After each setting, I reset the computer.
Greetings.

Producer and model of the projector?

Vivitek
DX881ST

Well, this projector's manual does not mention how the digital sound standard accepts this device.

Let the friend check two settings of the audio card.
Having selected this projector ie "marked" by clicking - please use the "Configuration" button and check what options are available. Stereo is indicated (or mono if available).

After this procedure, please use the "Properties" key and then the "Level" tab. It can not be on "0", 100% is OK.

By the way, this projector has only one 10W speaker.
Is it really giving?
Could the school management be persuaded to use the simplest set of two active columns?
They are not too expensive, and the effect is completely different.

Hello.
The level was set to 100%.
It does not work all the time.

The case with speakers is that if I buy it myself, I will have it.
I'm after a few purchases of things that were missing and it would be nice if I moved with this speaker.

However, if I do not go out, I will eventually buy used speakers and it will be after the problem.

Best regards and thank you for the response and help.