So I decided to make one of my own, and yes, it works!
So here's what i've done (every piece makes it a bit better, so, choose the ones you wish to do, or do all of them like i did!):
1. Cut the back cover to look similiar to the original desing from htc (Picture 1)
Just throw the first metal grill (the one on the back cover) to garbage, that's what i did As the speaker has a cloth on it, you don't need those grills.
2. Make some room for sound to echo inside the back cover (Picture 2)
I did 1. and 2. with normal household scissors.
3. Prevent the sound from the front of the speaker going to the back of the speaker and thus undoing some sound. Try to insulate the back a bit (Picture 3) I did it with 2-sided 1mm thick tape and left the protecting layer on the tape (green) so it doesn't stick to the back cover.
4. Open up the phone (Help to disassembly here), lift the speaker and the.. uh.. thing on top of the speaker off from the back housing carefully (2-sided tape keeping it in place) so you wont break it. Time to throw away the second metallic speaker grill! Use scissors to carve the speaker hole bigger (see speaker in picture 3), use the tape that kept the speaker in it's place as a guide to how big to carve the hole, but don't cut any tape off, the hole becomes too big if you do that!
Video 1 : Results of the mod, you should hear the difference clearly! Too bad i didn't have a video of an original Raphael, but i think you do have one there as you're reading this.
Video 2 : Comparing the results with and without the back cover. This shows how big difference does the "sound echoing space" inside the back cover (Whatever) do!
And last side note before you begin, i will not take responsibility of ANY damage etc you manage to do to your precious phone. I've broken one already, did the mistake to grab the speaker wires and the speaker stopped working as the wires cut off.
Also, be VERY careful with this mod, you're working with the interior of the phone! Please don't do this if you don't have any experience disassembling/reassembling mobile phones.
Hope this helps you as much as it did me! It actually sound better live than on the vid, too bad my camcorder saves the vid to some shitty format when recording to SD.
(Did i rickroll you btw? )