When a lithe, muscular, bald-pated outer-space super-powered individual goes through a pane of glass, it sounds like this:

But when a fat guy goes through an almost identical pane of glass in the very same comic, it sounds like this:

I am sure some fancy-pants acoustic engineer will saunter in here and make some mathematical arguments about sound waves and refractions through different cell types and whatnot, but at the end of the day I think we can all agree that what we need to settle this controversy once and for all is to throw more guys through windows.
I’m not sure you need all of the mathematics, just a bit of logic and common sense.
The physical condition of the first guy is, surprisingly, not necessarily relevant to the discussion. From the given pose alone, I can think of about five different ways he could be hitting the glass. (Having not seen the comic this is drawn from, I cannot vouch for which of these options, if any, it is.) In each of these hypothetical situations, only a smallish portion of the individual’s body is making contact with the pane – the glass is allowed to vibrate wildly at every point (other than the actual point of contact) up to the edge of the frame holding it. Hence, the sound gets a chance to build during the instant before the impact crosses the ‘shatter’ threshold. As this finally happens, and all edges begin to vibrate as well, the full-fledged ‘CRASH’ sound occurs.
The second guy, on the other hand, appears to have hit the glass with a much larger portion of his body – at the very least, the full shoulder. His body tone and physical condition are important, as they directly affect the available surface area for the moment of contact.* Due to this increased surface area (which, hitting a solid object, will briefly attempt to spread out before reaching the critical threshold), a larger portion of the window is damped by contact; there is less of it free to vibrate, thus producing the ‘KREESH’ sound effect (a somewhat muted version of the other effect).
Please note that this is based on logic. I have no guarantee that the mathematics you were expecting will verify my speculations.
*Also, it should be noted, because his jacket is not closed, it is possible it acted as a dampening surface in addition to the simple ‘general surface area’ option. The material appears to be bunched up somewhat around the shoulder, thus permitting an area where even non-contacting surfaces can be damped down before the pressure waves can flow across the surface.
You had me at “logic”.
I do believe my head just exploded. A tad bit.
from a draftsmanship perspective, there are so many things that are wrong with that fat guy panel, it boggles the mind. Perhaps the fat guy makes a different sound because the penciler chose to draw him a reality completely unrelated to the laws of physics and perspective that govern our world.
Or, maybe the penciler just sucks. The simpler answer is usually better…!
The fat guy doesn’t look american, maybe his sound effects have an accent.