@fksobroies first off you want to make sure that your speaker opening is cleared of any obstruction. Make sure that there is no debris, like pocket lint etc. that is clogging that opening.
Next make sure that all your settings are properly set to ensure you have sound on and that the volume is working.
If you do need to replace the speaker, and iFixit does not yet have a guide for it, use the instructions given by Samsung
[image|3071682]
[image|3071684]
[image|3071683]
or use the instructions [https://www.sosav.fr/guides/mobiles/samsung/galaxy-a30/haut-parleur-externe|from here]
While you work on your phone, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has the same problem as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.