Web Audio API Panner Node - how do I cut of sound on 100% pan?

I am looking at the web audio API spec and I use the panner node. It uses three values to create a 3D spectrum for sound.

When I pan 100% Left, I can still hear some sound on the right side(and vice-versa. Can anyone help with settings so that panning 100% to one side completely mutes the other ?

this article suggests that that maybe the panner does not fully cut of the left from the right: Web Audio API: How do I play a mono source in only left or right channel?

I have been experimenting with these settings - but so far none of the combinations I have tried fully mute left/right on 100% pan.

panningModel distanceModel rolloffFactor

Is it possible using the Panner Node to fully cut off the sound when panning 100%?