Can you overdamp the front wall?

I recommend buying F. Alton Everest's "Sound Studio Construction on a Budget" (covers all kinds of rooms) or the 4th edition of his "Master Handbook ogf Acoustics". You'll see that he advocates diffusion rather than absorption for front and back walls. RPG's Skyline diffusor is a favorite of his. I have a DIY diffusor based on the same theory, if you can saw 2" Styrofoam into strips, then short pieces. I have Skylines on my back walls and my DIY's on the front, and the room remains lively enough, not overdamped (though Styrofoam does some absorbing too). I think you certainly can overdamp a front or back wall, or a side wall too, come to that. If you can try diffusion, I'm sure you'll like it. Please get in touch if you should want DIY plans.

Tom's comments are correct, and the references are excellent as well. However, one aspect that Everest does not address (and rightfully so as these books have to have their limit) is how to handle this issue with different types of speakers. Planers, bi-pole, di-pole, and rear ported speakers all react differently to front wall diffusion and absorption. The front wall can actually be used almost as a tuning device. When you get the correct balance of diffusion, reflection, and absoption it can be bliss. The reference is very good on discussing how to calculate the total room absoption and diffusion and discusses how to balance it very well. Most people tend to overdamp rooms thinking that getting rid of more reflected sound will leave the sound that was intended by the speaker (or other) manufacturer. This rarely (virtually never) works as there must be an appropriate balance of frequency attenuation and diffusion over the entire frequency spectrum. There are also some good software programs that can help with this as well, such as the CARA 2.1 (which our company does sell, so I do have a vested interest there).

Like most things, It's a matter of taste. I have a project studio where I have an LEDE (live end dead end) setup where the entire third of the studio with the monitors (front wall, ceiling, & side walls) is covered with absorptive material (and carpet on the foor) and the back has diffusion. This minimizes the effect of early reflections and allows you to hear 'into' the room where the recording was made. Imagining is amazing with pinpoint accuracy but it has a character unlike any other listening room. In my music listening room (where I listen to classical music) I have two 2'x4' absorbtive panels mounted horizontally behind the speakers with about .5' between them - works for me. Try different amounts in different locations (as well as diffusion) and see what you like best.