Bluetooth transmiter dosn't require the line of sight to work but their are various parameter to each and each class of bluetooth device has a specific range to it. The Fm transmiter too won't provide a good quality of sound for you to listen. The best would be that you run a pair of analogue interconnectors from your Pc to your HT setup to enjoy the best possible quality,but that would add a lot of cost towards the good quality long run cable.