As a default KEF R Series speakers Link Connection is on but apparently quite loosely. I would advice to tighten the Link Connection and possibly check it once a year or two. Yesterday I took my receiver to local shop to be tested and nothing came up. Home I had distortion and volume drops in left and center channel and I was assuming that my receiver is dying. Retailer called KEF representative and asked if there were any reports of problems with R Series speakers and he described the problems I had. KEF representative suggested to check Link Connections after hearing the problems. I went home and connected my receiver again and tightened the Link Connections.. Distortion and volume drops were gone! So apparently Link Connections were loose when they left the factory and in 2.5 years they loosened so much in left and center channel that it started to drop out connection causing distortion and volume drops. For my luck everything is fine now and the problem was so small and easily solved. I thought it would be good to share this information for all R Series owners (might apply for other KEF speakers as well that use Link Connection) so they can be avare of this and possibly avoid getting some bad creeps!