Sound proble with Sony TV?

I have a Sony KV-32TS35 televison, and I have a problem: When I connect the TV signal using coaxial cable the sound is very very low and poor quality, I tried with another TV set and it works fine (the signal and cable are ok), but when I connect the same signal to my VCR and the VCR out to my TV using RCA connectors the sound is ok. if I used coaxial cable from my VCR the problem sound is the same. Please your help