Question [Q] sound hollow/reverb after install of slimkat 4.4.2

Hope itīs allright to ask here.

I rootet my Galaxy S3 ( I9300 ) with CF-Auto-Root-m0-m0xx-gti9300, 3 days ago and installed Slimkat ( Slim-i9300-4.4.2.build.5-OFFICIAL-4081 )

I have asked the people i since then have talked to how the quality they said it was ok but some of them allso said i sounded a little hollow or reverb ( dont know if this is the right word used google translate )

Anyone got an idea what i can do to fix this ?

thanks in advance