Slight noise/growl/vibration from taps

When you turn a tap on this slight sound/vibration only happens a at a certain flow rate and immediately disappears if you slightly increase or decrease the flow of water via the tap . There is a flip tap in the bathroom and if you flip it to full flow it bypasses the vibration/sound and runs normal.
This sound also appears after a few minutes using a shower that is powered from a motor in the loft.The noise in the shower continues for about 10/15 seconds after the shower has been turned off.
If you run one tap turned to the the point where the vibration is there and then turn on another tap the vibration sound disappears.
Although I don't think it is connected this sound appeared after a plumber fitted a new valve in the cistern of a toilet he may have used a isolator valve in the pipe that is about 6 inches from the cistern to cut off the water while doing the replacement. When doing this job for some reason he went into the loft where there are a 2 water tanks with ball stop cocks one is about 15x12x10 inches the other tank is about 36x24 inches and 24 inches deep. There is a occasional drip from the ball stop cock in the large water tank
I have increased/decreased the water supply via the outside stop cock but that made no difference

I would be grateful to hear of any reasons why this vibration/sound is happening and of ways to get rid of it.

Thanks

 

Use the search box at the top right of this page this site to search for 'water hammer'. There are a several causes and the remedy differs in each case.

From your description I'd check for pipes that are not properly clipped at the correct intervals first.

 

All the pipes are fastened solid with no movement.
A next door neighbor said that the because the stop ball cock in the large water tank in the loft has a slight drip drip leak it may be the problem but I thought this tank just supplied the hot water cylinder and there is no feed back from this tank to the cold water supply where the problem lies.