There are a few users who find themselves in this situation. And in many cases, it is spontaneous. The mobile audio stops working, and has had no fall or received any hits. What can be done in these cases?
1.- Identify if the speaker is
First, it identifies that the problem comes from the speaker. To do this, connect a headset and see if you hear sound through them. If so, then it is that the problem has to do with the speaker and not with all the audio of the mobile.
2.- Have you turned up the volume?
It seems logical and obvious, but, have you raised the volume of the mobile? On Android, there are several “volumes” so to speak. There is the audio of the calls, the multimedia audio, and the audio of the alarms. It may be that when you modify one of these volumes you have not modified the other. For example, when you are playing, if you raise or lower the volume, you are only modifying the media volume. So, press the volume up or down button, and see if there is a setting option to the right of the volume bar. If so, click on this option, and you will see how they appear several bars of volume that correspond to the other volumes of which we speak. If this is not the case, go to Settings> Sound, and here you will have these options. Just be aware that you do not have the volume down.
What if this does not work?
Now, it is possible that none of this works. That from day to day your mobile has stopped being heard by the speaker. In fact, it is a problem that many users of certain smartphones have had, and it is a hardware problem of the speaker itself. What can be done in such a case? A simple reboot of the mobile is the main thing. Restart your smartphone. If the speaker still does not work, it is recommended to access the Recovery menu, and restart the mobile. To access the Recovery menu, turn off the mobile, and press the power button and the volume down (if it is a Samsung is On + Volume Down + Home Button), but ideally you are looking for how to access the Recovery menu or Download menu with your Mobile in particular, because in each mobile can be different. Sometimes, when accessing this menu, the mobile hardware is reset, and that may solve the problem.
Finally, you can restore the mobile to its factory state. Under Settings> Backup and Restore, you will have the option to perform a full restore. Of course, you are going to lose all the data of the mobile, so before you will have to make a backup. This step is the worst, because it will take you longer, but it is the last option before buying a new mobile, take it to repair, or replace it if it is still under warranty. It is even possible that before replacing it, in the store where you bought it, restore it to see if the problem is solved, so it is a step that you can save yourself.