bitflipper, I live in a small town and they only had one sheet of the fiberglass so I may order some online. Were you suggesting making a fiberglass booth such as the one I made out of foam? Or were you suggesting some other way of using the fiberglass. Thanks.

The reason he creates a tent (in the video) is for precisely the reason i stated:  he doesn't want to hear the room reflections recorded at all.  (enjoyed the vid, btw)  The problem with your booth- and the ones commonly sold, is that unless you are using an omnidirectional mic, or recording vocals very close to a wall, they don't do very much.   They don't have any effect on the reflections that are coming from behind you and these reflections are being picked up by the side of the mic that is most sensitive.  Your treatments only control reflections from behind the microphone.  The mic is still hearing the "room" from your side of the mic.  
 
It's a mystery to me why your vocals are so much duller in your new spot.  From my experience, it simply should not be the case.  In any event, treatments placed behind a mic cannot have the effect of brightening the sound.  Are you running through any equipment (such as eq) that could be effecting the sound?  Is the mic facing the right direction? Were you in a very "live" room before?  Did it have especially bright characteristics (like a bathroom would)?
 
 

James, my vocal is being recorded completely dry. Nothing added to it. Mic is probably 8 inches in the foam enclosure and facing a little off center to the back right. The room before was not that lively. I just compared two vocals, one from the old house (no treatment whatsoever in the room) and the new vocal (with the foam enclosure).
 
The old house vocal has a lot more highs but seems thin. But is more clear and airy (if that makes sense). No noticeable reflections.
 
The new house vocal seems to have more body and not thin at all. But is somewhat more bassy. And I notice more bassy overtones. Or maybe more nasal overtones. Don't know exactly how to describe it. Hopefully I can work this out with EQ and such. And another mic might produce better results. I'm definitely not a whiz at vocal processing and there's probably someone that could straighten this with little effort.
 
Thanks for your input.

How does the vocal sound in the same room with and without the treatment.

chances are, you are never going to get the results you want with that foam box.
 
use your room.
 
but tame it a bit.
 
these:
 
http://www.audimutesoundproofing.com/audimute-sound-absorption-sheets-materials-that-absorb-sound-soundproofing-blankets.aspx
 
 
work great.
 
you probably only need 1 wall treated,
and you would face that wall,
with all the rest of the room acoustics in play,
centered on that wall, singing directly into a good quality condenser.
 

I had a 3 sided (plus a top) booth made from 4" thick foam and contact cement years ago in a tiny 8x11' mostly untreated studio. I hung it from a pulley on the ceiling and lowered it when i did vox tracks. it actually sounded best when I backed into the booth and aimed the mic in the "entrance" of the booth, and at me. By slightly pulling the mic in or out of the booth I could control how much room ambience i got. You would have to rotate the booth and do some tests to see which wall behind the mic produces the best result. The 3M 703 fsk fiberglass bit Flipper recommends is excellent for room treatment, my new room has a lot of it in key locations but I sure wouldn't sing next to it unless it was with a dust mask(LOL)

BlixYZ
Unless you are in a GREAT sounding room AND you want that sound in your recording, then there is no such thing as "too dead".  

I would agree with this statement. The idea is to eliminate the "room sound", IOW the effect of reflections within the room that skew frequency response and cause time-related smearing.
 
However, the real challenge is achieving "dead-ness" across the vocal frequency spectrum, because the ability of any absorbent material to absorb a particular frequency is a function of both its density and its thickness relative to the wavelength of the frequency you want to attenuate.
 
Low-density materials such as packing foam don't absorb much except at the very highest frequencies. Even high-density materials only affect frequencies down to a point where their wavelengths are about 4 times the thickness of the material or shorter. So if you're using, say, 1" of fiberglass, that'll only have an appreciable effect on frequencies with wavelengths of 4 inches or less. IOW, about 250Hz and up.
 
Furthermore, the attenuation is non-linear, having a greater effect the higher up you go. This means you could be totally killing frequencies above 2KHz but doing nothing for the fundamental, which might be in the 150-200Hz range for a male vocal. The result: dull and boomy.
 
The answer is thick, dense materials. The density of rigid fiberglass is given as pounds per square foot. The most commonly-used type is 3 lb, but they go up to 6 lb. You need twice as thick a piece of 3lb material to get the same result as the 6lb material, but it'll work just as well. You can even use non-compressed fiberglass - the stuff in your home's attic - as long as it's thick enough (but you'd need 24-36" of it, so that's not practical unless you have a very large room).
 
As for how to construct it, that depends on how ambitious you are. Ideally, you'd surround yourself on all sides (including above you) with 3 or 4 inches of 3 lb. compressed fiberglass.
 
You can achieve this to varying degrees by constructing free-standing panels ("gobos") that can be moved around, stored in one corner when not in use, or reconfigured for recording things other than vocals.
 
I'd start by building two such panels and placing them to either side of the microphone in a V configuration. Later on you could add two more and situate them behind you, then make one more to either lay over the top of them.
 
I currently have 8 of them and need 1 or 2 more. They're 2 feet wide, the standard width of fiberglass panels, and 6.5 feet tall including the wooden feet that elevate them 6 inches from the floor. If you're very tall you could simply raise them up higher.
 
If possible, have at least a 4" gap between the gobos and any walls or windows. I have enough room here to allow a 12" air gap to the closest window, but I still intend to cover said window with additional fiberglass when funds allow. I'm thinking about hinged plywood shutters with fiberglass over them, as they would also provide additional security from break-ins when latched shut.

 
 
1268 posts in a single thread on the subject  :  How I built my bass traps...
 
 
 
 

that's overkill, eh?
 

I remembering using that thread as guide when I built my bass traps. I have 9 of them in my room.