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Your Roland speaker / PA, if the sound source being given to it is not fuzzy, but the sound output from it is, then you have an electronics problem in the amplifier circuitry. It will most likely need electronics repairs. Distortion in sound is caused by the failure of various components in the sound amplifier circuitry, when it is not caused by simply overdriving the speaker grossly - which I presume is not the problem.
How old is your BA-330 ? measured from its date of purchase.