Is it the Mac or the Headphones that Have the Weak Signal?
I have a Macbook Pro 15" 2011 and an IPhone 6 plus. 

These headphones worked perfectly with the iphone 6 but would stutter with the macbook which has an older bluetooth adapter. 

I had a spare usb bluetooth 4.0 adapter lying around the house which I bought for very little money off amazon and with that connected the headphones work flawlessly again.

Some have said that its either the mac or headphones and it may be a combination of both but in my case it was the mac.

Hope that helps.