TV and sound bar volume not same

[opo009]

I have a Sony kd-xe8599 TV and Sony ht-xf9000 soundbar. Their volume level can not be the same. For example when TV volume is 50,  I turn the soundbar on and sound bar volume is 50 I turn down the volume to 30. Now tv should be 30 too if I disconnect the soundbar to use only tv's sound. But when I do that,the tv volume is still 50. Before I had a LG sound bar and it worked very good, you control both tv and sound bar volume always at the same level with tv remote. Sony can't do this? Anyone help me please. Thanks a lot. 

[royabrown]

Start with sound bar is 50 and TV is also 50. Turn down soundbar to 40. Disconnect sound bar, I expect the TV is still 50. Now turn down TV to 35. Then connect sound bar again. I expect the soundbar to be 40. Now disconnect sound bar again. I expect the TV to be 35.

This is how it should work; the TV is 20 Watts, while the soundbar is 300 Watts. If they have the same number, the TV will be too quiet, or the soundbar will deafen you, with its 15 times more power. 

Have you ever ever heard of Nigel Tufnell?