lined 4" of OC703? You're a moron.
Perhaps in some peoples eyes. Thats why I routinely post my disclaimer here.
Roxul Rockboard 60 (which is what I use) is more dense at 6lb density than 4lb density of the 703.
Hmmmm, in that case, your density hypothisis would suggest concrete should have better absorption coeffiecents than Roxul Rockboard 60....AND it would have doubled as a great TL barrier at the same time.
In that case, I also belive your assessment of me fits you better. Like say ... a glove.
It's not a square. IIRC I made it 5x7x8.
Oh, my mistake. It looked like a square in the pics. My apology in that case. btw, is " IIRC" an American or European standard?
Regardless modes are not much of a concern in a booth
I believe I spot another hole. But I don't think it matters if I fill it or not. Considering your previous hypothisis, I believe density may enter the picture here...and I don't mean the Roxul.
where I'm recording vocals with peoples mouths on a SM57b and mics directly on guitar amps and even so it's VERY DEAD box.
Unfortunately, DEAD doesn't translate into low/mid frequency absorption very well nor into TL. Nor does a mic with a close proximity mouth prevent it from doing what its supposed to do. But what a dynamic mic DOES do is provide a "proximity" effect under those circumstances. Good or bad depends on what your judgement system tells you.
Length(7')
Mode Frequency
1 0 0
80.7
2 0 0 161.4
3 0 0 242.1
4 0 0 322.8
5 0 0 403.6
6 0 0 484.3
7 0 0 565
8 0 0 645.7
9 0 0 726.4
WIDTH (5')
Mode Frequency
0 1 0 113
0 2 0 226
0 3 0 339
0 4 0 442
0 5 0 565
0 6 0 678
0 7 0 791
0 8 0 904
0 9 0 1017
HEIGHT
001 70.6
002 141.3
003 211.9
004 282.5
005 353.1
006 423.8
007 494.4
008 565
009 635.6
I feel generous today.
Lets take a look at something. As you can see here notes produced within the first 12 frets on a guitar will produce notes within the axial mode band of your booth. ie...LOW E= 82.4hz A on 6th string 5th fret=440hz even A4 is only 880hz. Now, do I have your attention?
Let me quote something from here.
http://www.recordingeq.com/EQ/req0400/OctaveEQ.htm
THE BASS RANGE
Covering about 1.5 octaves, from 80 Hz to 250 Hz, this range of frequencies determines the "fatness" and "fullness" of the instrument's sound. Equalization is usually applied centered around two frequencies, 100 Hz and 200 Hz.
For guitars and bass, the 100 Hz range tends to add body and fullness. Excessive energy in this range tends to make these instruments sound "boomy.," This range of frequencies is still greatly affected by the Fletcher-Muson Effect; this means you will need to listen to the mix and instrument both loud and soft. Similar to how the 50 Hz range affects the bass and foot, the guitars should sound fatter when played loud, not boomy. Reducing the 100 Hz energy on the guitar will usually cause distinction between the bass and guitar parts. The lowest fundamental frequency on a guitar is around 80 Hz.
For vocals the 200 Hz range determines the fullness of the vocal. This range can often be reduced to increase distinction on the vocal. If, however, boosting in higher frequencies on the vocal makes the sound "thin" or "small" a boost of 200 Hz. will restore fullness.
When 100 Hz is reduced on a guitar or bass to reduce "boom," at small boost at 200 Hz can be helpful to keep the instrument from sounding "lumpy" (certain notes hard to hear and others standing out). The guitar and bass have almost equal energy at their fundamental and 2nd harmonic frequencies. Thus if a range of notes becomes hard to hear because of a at lot of 100 Hz, reducing energy at 100Hz and adding energy at 200 Hz will help the notes be heard again.
It appears from the axial modal analysis at your booth dimensions, ALL the length, width modes fall within "almost" the entire fretboard on a guitar. Not to mention the height. Unfortunately, my satire failed to mention superchunks at the wall/ceiling intersection. Hmmm, did someone mention "boomy"
The MID RANGE
Covering about one octaves from 250 Hz to 500 Hz, this range accents ambience of studio and adds clarity to the bass and lower-string instruments (Chello and Upright Bass). Too much boost can make higher-frequency instruments muffled sounding and low-frequency drums (foot and toms) have a cardboard box quality. Equalization in this range is applied at many frequencies but most often between 300 Hz and 400 Hz.
The lower part of this range (250 Hz to 350 Hz) is sometimes referred to as "Upper Bass" and is used to increase distinction and fullness on the vocal, especially on female singers.
The Lower Mid Range in general can be viewed as the "Bass Presence Range" Increasing this range gives clarity to the bass line and the lower-register of pianos and organs. Clarity and distinction can be obtained between the foot drum and bass guitar by both reducing the foot and increasing the bass guitar in this range, at the same frequency.
Did someone mention vocals? No amount of eq will remove modal resonace in your booth. And the mic doesn't know the difference nor care. Neither will 2" Roxul in this range.
Furthermore, since resistance absorbers work via the 1/4 wavelength principle, and resistance is the principle which turns energy into heat, via GAS FLOW, it stands to reason, the density has a bearing on GAS FLOW. No gas flow...no absorption. Like CONCRETE. Hence, the denser the material, the less absorption, which is true of the opposite..complete lack of resistance equals no absorption either. This is why 3lb density has better absorption characteristics. In regards to 4" vs 2" with an airgap, it depends on your available space and budget. HOWEVER, NOW put a 4"airgap behind a 4" panel of 3lb density fiberglass...and then listen to the modal range of YOUR booth. an 8" 1/4wavelength translates to a 32" wavelength, which is approximately 425hz
vs Roxul 2" with 2" airgap = 4" 1/4 wavelength translates to a 16" wavelenght which is approx 850hz.......now maybe you'll get my drift.
Yes, its true this takes up valuable interior space...but what the hell..you've had plenty to begin with. You just didn't maximize the possibility of the performance of your booth. But hey...who cares..its only rock and roll. On the other hand, most people do not have the luxury of this much space...but you did. I only mention all this stuff for the benifit of others, so they understand the limitations of booths sized for "typical" home studios. And this isn't even addressing Transmission loss.
It's called SATIRE, It's a JOKE.
So was mine. Especially the "six leaf" thing. Unfortunately, you didn't get mine as well. However, it's what I DID get that was the point of my version of satire.
In closing, might I add...
Given....
12 2x4 perimeter/rim joists and plates(floor, walls, ceiling)
24 2x4 studs min.
5 2x4 floor joists
5 2x4ceiling joists
Approx (46) 2x4 at roughly $3 per 8'= roughly $138 (Double that for a DOUBLE WALL TWO LEAF ASSEMBLY with an inside out construction ie....a DRUM BOOTH.)
" 35 sq' 3/4"" flooring ply at roughly $1 per sq'= roughly $32
" 420sq' ext. and interior sheithing = roughly 6 sheets 4'x8' @ min. $6 drywall interior, and 7 sheets 1/2" 4'x8' ply exterior @ min $10 per sheet. = $106(Double that for a more robust TL
" 200sq' stud/joist cavity batt insulation =@ roughly $.22 per sq'= $44
(1) 32" Hollowcore Luan door prehung with jamb. Min= $57
http://www.homedepot.com/Doors-Wind...ation?langId=-1&storeId=10051&catalogId=10053
or (1) 32" SOLIDcore Luan door with jamb. Min= $ 125 (Absolutely required for best TL within reason)
(1) Door Latch set Min $12
(1) Wetherstrip set Min $15 OR (2) Good Automotive door seal stip - Min-$40
Electrical Min $15
Light Min $7
Add Roughly 225 sq' Roxul 2" for complete coverage (walls and ceiling) @ $49 per 48 sq' coverage(6 2'x4' panels)= 5 packs = Min $249
OR roughly half that amount for patchwork(better absorption due to edge effect) = Min $125
So, at the low end, I estimate a minimum of $551 for a booth of your size. In respect to your $200 cost....all I can say is...where do you shop?...I know a contractor who would love to have access to those prices.
and btw....
Acoustical Performance ASTM C423
CO-EFFICIENTS AT FREQUENCIES RHM 60 / RHM 80
Thickness 125 Hz 250 Hz 500 Hz 1000 Hz 2000 Hz 4000 Hz NRC
2.0” 0.32 / 0.43 0.81 / 0.78 1.06 / 0.90 1.02 / 0.97 0.99 / 0.97 1.04 / 1.00 0.95 / 0.90
with 2'' airgap the low frequency coeffiecent will increase. By how much is anyones guess.
vs...
Product thickness mounting density 125hz 250hz 500hz 1000hz 2000hz 4000hz NRC
703, plain 4" (102mm) on wall 3.0 pcf (48 kg/m3) 0.84 1.24 1.24 1.08 1.00 0.97 1.15
And yes, it is more expensive. You get what you pay for. I paid $600 for 4 sheets of 4" thick 4'x10' panels and 2 sheets 3" 4'x10' panels of Knauf(same coeffecients as 703) for my CR alone.
You're the kind of person that makes me not want to spend any time helping anyone out on internet forums.
I make you? How, I don't remember twisting your arm.
However, I won't offer my opinion of you.
What I will offer is my disclaimer. I never claimed to be more than an HR enthusiast who happens to know enough to get me in trouble sometimes. If thats the case here...be my guest...it won't be the first time.
You would seriously rather have this person spend $1000 on 4 big wedges of foam and some stands with a little glass window than maybe have then go to home depot and build something themselves that is better?
I would rather inform them of the limitations of small booths and the flaws of your view.
Get your know it all ass the hell out of here.
Your the one that says I don't know anything. I believe you even called me a moron. However, no, I won't get the hell out of here.
You clearly aren't helping anyone.
On the contrary, I believe the post before yours proves your hypothisis is in error.
[
