Default Knock-on question

I don't have a G2 but I absolutely love the knock-on feature which has been brought to other devices using custom kernels. On my device at least (Nexus 5) enabling this feature entails a significant battery drain.
My question for you G2 owners is: are you able to disable the feature on your phone, and if so, is there any effect on your battery life, i.e. is it better without knock on?

Sent from my Nexus 5 using Tapatalk
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POSSIBLY MY NEXT
Moto X+1

CURRENT
Phone :: Google Nexus 5
ROM :: Mahdi-ROM 2.5
Kernel: ElementalX

RETIRED / SOLD / STOPPED WORKING
Phone :: Samsung Galaxy S3, HTC Desire Z, HTC Desire, TMobile G1

BRIEFLY FLIRTED WITH
Phone :: Google Nexus 4, Samsung Galaxy S i9000, Google Nexus 1