The tutorial you linked to doesn't explain how to implement any of that stuff. But it doesn't matter because the panner in the article is fine as it is. Simple

The tutorial you linked to doesn't explain how to implement any of that stuff. But it doesn't matter because the panner in the article is fine as it is. Simple panning is often the best option in music, since filtering your sounds will just make your mix sound bad on common sound systems. Left/right delay will be great on headphones but create phase effects on common speaker setups, often making things worse as well. I don't think a general-purpose tool should add potentially unwanted effects like that.