Yes.
Yes and if you read the post, you can see that I said the same thing.
The quest ultimately leads to treatment, but it's a self discovery. It's an informed purchase. You don't need to treat a room completely for doing basic recording. Basic, as in
acoustic guitar and vocals. You can get AMAZING results that way, but you do have some limitations. It is NOT so good when mixing an album or recording things like drums , Bruce Dickinson, choirs and stuff. (Yes sorry, your mixes won't translate well to other people's stereos. Do your recording, try to mix it .. and if you love your music and think it deserves more, hire a mixing engineer at the end of the process)
If you want to mix everything and go-for-pro, then well, time to shell out the big bucks.
Treatment is essential for Mixing , Mastering , and High SPL situations.
Treatment is not so essential for basic yet high quality home recording.
Yes the bass will bounce around. Yes you can kill the highs and mids if you're not carefull. That's exactly what I said in the above posts.
Yes clap your hands and try to place your foam so as to reduce some of that echo of your, i assume, relatively small space. Don't let anybody tell you this isn't a good place to start. The room will feel warmer. It will take on a different feel then the rest of the house. This is good. Don't overdo it.
Inspect the spectrum of the resulting sound (look up "Impulse Response") if you're really adventurous and you'll see that there are peaks and valleys in the spectrum. That's constructive and destructive interference aka "room modes".
(Voxengo SPAN is a free spectrum analyzer. They also have some impulse capture tools i think. )
Just use your ears.
This is precisely why you'll read about people saying that the sound is better behind the couch, or near the window, or behind a book case, little to the left of the recording desk ... experiement and have fun.
It's not so much about the dapening of echos in the room, but more about the location's effect on the tone of your sound (the spectrum).
Dampening the echos "or reflections" is critical for vocals though.