Don't know about the type of your hardware, but your description is very light. In order to further isolate the problem, I would do the following:
1. Replace the speaker with a working one. If this works fine, then it is really the speaker that is broken. If however the intact speaker shows the same problem when connected to the same channel, then the amplifier/equalizer has an issue.
If it is by this confirmed that the speaker is broken look at step 2:
2. Inside the speaker there is usually a frequency separation filter. Either the bass loudspeaker is damaged or the filter. Ideally you could exchange filter and loudspeaker with parts from a working speaker box and find out by this which component is defective.
3. Once you have identified the defective component, try to find out the brand and type and perform an internet search.
4. If you don't find anything, bring the whole thing to a repair service, they can order the spare part.
If you are too lazy or technically not very skilled, go directly to step 4.
Hope that helps
Critter
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Download Music from the Internet
