Just the Tip.
If the end was square-cut, the tip itself would be able to resonate, giving an emphasis to whatever sound frequency wavelength math'd out to the length of the tip.
For one with a 12" body it would be somewhere around 500Hz; that would definitely add some aggression to the Modular Growl.
Speaking of... I have a tip on mine. Maybe where you notice the slight difference in sound you talked about a couple weeks back.








