How I built my bass traps...

[Cojo]

Here's a picture of my front corner to show you what I meen. One trap on the floor in the corner and one on each side along the side and front wall.

[Scott R. Foster]

Those look great Cojo.

You are getting good results on those horizontal floor panels because they are in proximity to a floor/wall corner... if you tip those panels back at a +/- 45 d angle so they lean against the wall you'll have affected a true corner mount.. and get even more LF performance boost.

Xmos:

You might try adding some egg crate return air grills to facilitate absorption by the insulation you added to the ceiling. You should be able to get these in a size to fit your ceiling grid and merely replace a few of the ceiling tiles. If you can find an inexpensive source [they make them out of everything from hardwoods to plastic] add one of these in each corner and perhaps a couple over head. Try a HVAC supply house if your local big box hardware store does not carry such items.

Also, try moving the microphone along the height, width and length axis of the room from the listening position in small increments - both forwards and backwards - and take note of changes in the most severe peaks and dips. This will help you identify whether a particular peak/dip is in fact modal [if it modal it will wax and wane smoothly as you move the mic] or instead, a reflection/SBIR issue [these can be persistent or suddenly appear and disappear with movement, but typically they won't smoothly change with mic position].

As instructed above, move your corner panels to tri-corners to enhance LF performance.. either slide them all the way flush to the ceiling or the floor.

Consider getting some heavy drapes for the window behind the listening position.

Good Luck!

[Glenn Kuras]

[QUOTE=xmostynx;1109539]no problem man! i kinda feel bad, i need to atleast buy you guys a drink



PBR would be just fine with me.

Glenn

[dim light]

I dig your lamps man... nice studio!

[xmostynx]

so- i moved bass traps around for the day-

and i still can't get a hold of 60 or 120- in my upper 5k area- right below 6k i have a huge dip- i can't find that either... its much larger than my 60-120 problems..

here is a graph of the room...

its the best looking one i've had so far-



let me know....maybe i have to live with those nulls? i shure hope not!!!

after 6- 6 inch traps- how bad is this graph? should i be looking maybe to move my monitor setup?
i think thats my next move-

[xmostynx]

this is as close as a picture that has no traps in this room..

i've kept the mic in the same spot- and monitors in the same spot-

this is no traps

[xmostynx]

aww guys- i'm just messing around with itunes- and i pushed up some 60- 8 dB or so 125- 4-5 dB or so- 1k just a little and 8k just a little...


would it be bad if I introduced a little eq on my master fader in PT???! i know this is like NOOO, but its ONLY a few dB...and man it makes everything i listen to sound so freakin' good...


i'm so anxious to get this room solid

[Glenn Kuras]

Originally Posted by xmostynx

aww guys- i'm just messing around with itunes- and i pushed up some 60- 8 dB or so 125- 4-5 dB or so- 1k just a little and 8k just a little...


would it be bad if I introduced a little eq on my master fader in PT???! i know this is like NOOO, but its ONLY a few dB...and man it makes everything i listen to sound so freakin' good...


i'm so anxious to get this room solid

JUST SAY NO!!!!!!!!!!!!

Out of those 6 traps that you have, how many are straddling corners?

Glenn

[xmostynx]

two of them- one is on the floor in the back corner- i'm gonna hang it tonight-

you know Glenn when i put the one thats not hung up yet in the corner and ran the tests again- there was no difference in the 60-120 or 5-6k area..

what should i do?

[Cojo]

Originally Posted by xmostynx

two of them- one is on the floor in the back corner- i'm gonna hang it tonight-

you know Glenn when i put the one thats not hung up yet in the corner and ran the tests again- there was no difference in the 60-120 or 5-6k area..

what should i do?

Don't expect the graph to be flat, it woun't, with that said I think your graph looks really good. Just two nulls at the low end of the spectra! But the important thing, -How does it sound? Does it sound better?

[xmostynx]

Originally Posted by Cojo

Does it sound better?

yea it sounds WAY better- I just have such a shitty translation between the bass in the room and how it sounds on other systems...always sound either

A- way to much-
B-way to little

or C- bass and kick don't lock together well on other systems..

i'm going to move the mic around the room to see where my bass problems are in a little bit (i'm going to skip my english class for the day)

once i find out where the nulls are- if they are indeed in the corners floor/ceiling i'm going to move the traps out from the walls a bit-

my problem with placing them on the floors are my lovely CATS!

chester and elle- (white and black) or (fatt and skinny) think these are scratching posts! and last night- i made a dive over my sleeping girlfriend to shoo chester (the big fatt white cat) off my bass trap!

-though the graph does look ALOt tighter- and the whole room sounds tighter.

i'm going to throw a rough mix together tonight- just a set of drums and the bass guitar- to see how well a rough mix will translate out of this room.. thats what i should be testing- i think now- its just a matter of re-learning what my room sounds like..

this was all lots of fun- and its not over yet!

everyone here has been big helps

Glenn idk WHY your drinking PBR! but i'll glady buy you a few if you make your way out to pittsburgh, I'll have a guinness tho!

[Glenn Kuras]

Originally Posted by xmostynx

Glenn idk WHY your drinking PBR! but i'll glady buy you a few if you make your way out to pittsburgh, I'll have a guinness tho!

I only drink Guinness when touring in the UK.. But, I would be crazy to turn you down. The best beer is FREE BEER!!

I think the problem with your room has more to do with you only having 2 bass traps straddling corners. Think more in terms of 6 to 10 OR MORE, straddling corners. You may want to try taking down the ones behind the speakers and straddling those.. JUST MORE MORE MORE.. At this point though I would face the fronts with FRK if you can. Either that or think about building some super chunks for the corners. 60hz is not as easy as you think and plain rigid fiberglass does well, but not killer at 60hz.

Glenn

[xmostynx]

how far should i space these beasts from the wall?

i ran some pink noise, and used an analyzer plugin from waves- and moved a 57' around the room, pointing it in corners etc. found LOTSSSSS of 30-250 all over the corners-


so you guys are totally right- bass builds up BIGTIME in the corners- i'm talking like 15dB max peaks - its my front and back corner-

can't find 5-6k anywhere around here...so thats a mystery problem..


as far as the corners go- and the ones on the wall- i'm going to put 2 more traps in the corners, and then 2 on the sides for early reflections-


that means- i have 4 traps in the upper left corner, and back left corner- 2 on my front wall behind my monitors, one on my back wall inbetween the windows- and 1 at my left side- for early reflections layed on his side- and the same goes for the one on the right-

the question now- spacing! i'm off to read ethans suggestions on his site again-

thanks guys! i'm going to go through all the information i have gathered at the end of this project- and make a nice little package-

[xmostynx]

i answered my own question-

i read some of ethans site-

i measured the gaps i have my traps at now- looked at my graph- (with 5 traps hung)
and decided if i moved them certain distances from the wall i would be able to control more low end response..

hey correct me if i'm wrong- but since my corner traps are about 1 foot out from the corner- that would make them most effective till about a little lower than 300Hz..

i do believe ethan suggested having a air space behind each trap of about 1/4 the wavelength ... if anyone one wants to contribute why i didn't quite understand- something about maximum velocity- etc.

so i did the math
wave length in feet= 1130 (speed of sound)/(frequency)
x=1130/300
x=3.76 feet
1/4 of that wave would be
3.76/4=.94 feet

that would be what? about 9 and 1/2 inches?

a bass trap at that gap would be 'capturing' waves as far down as 300Hz...am i doing this correct?

so if I was to do the same math for a 60Hz wave- i would have to have an air gap of about 4.75 feet from the wall.

would this be normal practice? or impractical?


the other problem in my room is 120Hz- that would result in a space of 2 1/2 feet (about) and then 120hz would be better absorbed...

if i'm doing any of this right-
then this is my game plan:
1) move the corners out, 2 1/2 feet from the wall (in both major corners.)
2) move all "full range absorbers" that are on the front and back walls out from the wall 9 1/2 inches.

giving me more absorption in the corners all the way down to 120Hz, and giving me more absorption on the front and rear walls down to 300Hz.

this should improve my room acoustics greatly?

assuming i did everything correctly?
if i'm doing this right- i'm stoked!
i still have 4 more traps to hang up- so i was hoping to space these and get a good response with 5 and then use the last 4 to really focus on smoothing out the low end as much as possible!


get back to me guys i got the day off tomorrow to mess around.

[Cojo]

Hi Patrick!

I havn't checked your math but I think you theoreticly half right.

You want them a 1/4 of a wave lenght from the wall but also you want them a 1/4 of a wave length thick! (in theory) I practice th best way is to space them as far from the wall as the traps are thick. If you put them farer away they will go trap lower but you will loose efficency so it's not worth it.

This is my understanding of it, I may be wrong, I may be right!?

[xmostynx]

Damn.... That's huge almost five feet of trap to catch a quarter of a 60Hz wave?! FVCK!!! That's a lot... Ha ha anyways I'm going to move my traps out the distances from my earlier post and then measure and post the graphs. See where it gets me! I want to be able to mix in their and be done with traps for a bit by Friday.. So let's hope I can achieve something nice!

[dim light]

You don't want dips in the low end - you want boost all the way up there in the ganja sky!

Regards,
Low end Rasta...

[bpape]

Moving the corner absorbers out will shift the peak in absorbtion.

I'd agree with Glenn that you're looking at just needing additional corner placement.

The 60 and 120 are multiples of each other - my guess is that seating placment and monitor placement tweaking would be the way to attack these.

Bryan

[fcorl]

So, a quick basic question.... should I go 2 inches or 4 inches thick (insulation) on the broadband absorbers? How thick is optimal on the corner traps? Is 4 good enough on the corners?

[Glenn Kuras]

Originally Posted by fcorl

So, a quick basic question.... should I go 2 inches or 4 inches thick (insulation) on the broadband absorbers? How thick is optimal on the corner traps? Is 4 good enough on the corners?

4" is good, 6" is great, but cutting them into 2'x17"x17" triangles and stacking them floor to ceiling it OUTSTANDING for bass traps. If you have enough bass trapping then you can use 2" for early reflections (better known as 1st reflections) for side walls and ceiling.


Glenn

[fcorl]

Originally Posted by myfipie

4" is good, 6" is great, but cutting them into 2'x17"x17" triangles and stacking them floor to ceiling it OUTSTANDING for bass traps. If you have enough bass trapping then you can use 2" for early reflections (better known as 1st reflections) for side walls and ceiling.


Glenn

Great! Thanks, I will do the stacked triangle "thing" in all four corners and a bunch of 2" panels on the flat walls, above my drums, and maybe even a couple bridging the corners between the walls and ceiling. So, a solid corner trap is best?

[fcorl]

EDIT:

Hahaha... well just finished building two 2'X4'X4" frames for the "early reflectors" on the flat walls (photos coming). I used "Cojo's" hole cut-out method for the frames with an initial plan of using 4" of mineral fiber. I wanted to use smaller wood, so I used 1"X4" instead of 1"X6". Half way through I remembered a 1X4 is really roughly 3/4"X3.5", so I ain't gonna' get 4" of insulation inside the frame. So rather than waist the wood and the work, I am going to use 1 piece of the 2" Auralex mineral fiber and 1" piece of OC 703. How does 3" early reflectors sound for the flat front, back, and side wall treatment?

I noticed Cojo left his wood frames exposed, is there any advantage of disadvantage to this. I was planning on covering mine with fabric.

[Glenn Kuras]

Originally Posted by fcorl

EDIT:

Hahaha... well just finished building two 2'X4'X4" frames for the "early reflectors" on the flat walls (photos coming). I used "Cojo's" hole cut-out method for the frames with an initial plan of using 4" of mineral fiber. I wanted to use smaller wood, so I used 1"X4" instead of 1"X6". Half way through I remembered a 1X4 is really roughly 3/4"X3.5", so I ain't gonna' get 4" of insulation inside the frame. So rather than waist the wood and the work, I am going to use 1 piece of the 2" Auralex mineral fiber and 1" piece of OC 703. How does 3" early reflectors sound for the flat front, back, and side wall treatment?

That should work fine for the 1st reflections

Originally Posted by fcorl

I noticed Cojo left his wood frames exposed, is there any advantage of disadvantage to this. I was planning on covering mine with fabric.

Either way will work fine.. You just do not want to cover the backs with plywood.. Well you can cover them with plywood, but it is best leave it open and space it off the wall 2" if you can.

Glenn

[xmostynx]

hey guys- i just wanted to say-

building these 9 traps- were the best thing i've ever done for my room..

my mixes don't sound funky when you bring them to another system, and the low end that these Hs-50's put out...i was shocked.

everyone who helped on this thread...awesome.

when i bring a song i just mixed from my room to my car, its just killer...when people smile at how good their stuff sounds...ahah

now i'm off to build a new PC and what not

[Cojo]

Originally Posted by xmostynx

hey guys- i just wanted to say-

building these 9 traps- were the best thing i've ever done for my room..

Great!!!

I noticed a great improvement when I went from 6 to 8 traps. It was almost like there where some hidden treshold you had to come over... Did you noticed the same?

Good luck with the PC build! thumbsup

[xmostynx]

yea..i also moved my setup- and ran around my room with a 57, and an analyzer on it (in PT) and i just cranked pink noise at 85dB put ear plugs in, and then looked around for certain freq's buildups- and then i placed bass traps where the analyzer was showing buildup...it worked amazingly...

my room sounds alot better than alot of places i've mixed in..its been like 2-3 weeks? and i've noticed a 100% difference in how well my mixes translate...its nice to place instruments in a mix and know- thats where they are going to stay..

i'm as fuking stoked as ever, and my confidence in my mix choices will just allow me to learn more..like tape saturation in digital systems, and now getting that 'ssl' sound..haha instead of...WHY IS MY KICK NOT THERE!!!! AWWW MAN THE CYMBALS ARE SOOOOOO LOUD! hahah

[Glenn Kuras]

Originally Posted by xmostynx

yea..i also moved my setup- and ran around my room with a 57, and an analyzer on it (in PT) and i just cranked pink noise at 85dB put ear plugs in, and then looked around for certain freq's buildups- and then i placed bass traps where the analyzer was showing buildup...it worked amazingly...

my room sounds alot better than alot of places i've mixed in..its been like 2-3 weeks? and i've noticed a 100% difference in how well my mixes translate...its nice to place instruments in a mix and know- thats where they are going to stay..

i'm as fuking stoked as ever, and my confidence in my mix choices will just allow me to learn more..like tape saturation in digital systems, and now getting that 'ssl' sound..haha instead of...WHY IS MY KICK NOT THERE!!!! AWWW MAN THE CYMBALS ARE SOOOOOO LOUD! hahah

Aint life grand. thumbsup

[aapee]

Here is some pics of my contruction. Seven panels, three SC and two tubetraps in CR and eight panels, one SC in tracking room. Huge improvment in acoustics.

aapee

[David-Morpheus]

I have been finishing some more traps for my live/drum room (I already have 7 in my control room)

here are some pics

empty frame

[IMG]******//www.morpheusmultimedia.sk/studio/progress/frame_empty.JPG[/IMG]

insulation filled in

[IMG]******//www.morpheusmultimedia.sk/studio/progress/frame_filled.JPG[/IMG]

and the final finished bass trap

[IMG]******//www.morpheusmultimedia.sk/studio/progress/frame_finished.JPG[/IMG]

david

[Cojo]

Originally Posted by aapee

Here is some pics of my contruction. Seven panels, three SC and two tubetraps in CR and eight panels, one SC in tracking room. Huge improvment in acoustics.

aapee

Nice! You've been busy!