How I built my bass traps...

[xmostynx]

here are the frames i built..


i went as cheap as possible with the wood...cojo was using (i think) 1x6

instead i used 1x2's to avoid cutting holes in them...here in pittsburgh a board of 1x6x4 was like 5 bucks..the 1x2x8's are only 1 dollar and change.

so the total cost of all the wood, to build 9 bass traps with the dimensions 2x4x8
was only

49.50


this is the first one...i have 8 more to go! going to walmart with this one to make sure i get the right amount of fabric to cover them

sorry for the shitty quality pic...i took it with my blackberry.
i'll take better ones with the digi later.

[Cojo]

Originally Posted by xmostynx

here are the frames i built..

How are you progressing? Have you put in the insulation yet?

[Scott R. Foster]

Nice and light.. I likee. What will you fill it with?

[xmostynx]

Hey guys! I have been moving right along! I got some AWESOME pictures!

i got real sick on monday night with some food lingo from wendys..spent the night in the ER- it was a mess! literaly! haha


anyways...feeling better now. I got 2 traps done..like i said awesome pictures

i got mineral wool insulation at a killer cost so i'm filling them all with that.
they look so nice with the fabric stretched on them nice and tight.
i'm hoping to put up some nice pictures up tonight of everything.

with 2 up already, you can already start HEARING low end...



im excited to get all 9 up!

thanks alot guys for all the great help...will post up later tonight!

[Glenn Kuras]

Yes please post some pictures when you are done.. BTW if anyone needs some mineral wool or 703 check out this thread for some ideas.

http://gearslutz.com/board/showthread.php?t=101748

Glenn

[xmostynx]

allright guys, got 2 up hanging...got 7 more to go! wanted to make sure my plans where going to work before i made all 9!!!

hope you enjoy the pictures

[xmostynx]

upload restraints! post more later!

[Scott R. Foster]

What is the thickness of the frame - 8"?

Will there be a full 8" of mineral fiber in each panel - and what flavor of mineral fiber?

[b17m4p]

Hello everyone,

I have found this entire thread very informative and a great read!

I would like to also attempt to build traps like these but I was hoping for some input on the best placement/ammount/etc.

I should note that I am building these just for listening pleasure, not for audio production. I have a very rough scetch of my listening room attached.

Here are the possible positions for panels. Which sholud I go for, in what priority order and in what thickness?:
Corners Behind Speakers 6" thick at 45 deg angle (cealing to floor yes/no) {speakers would end up very close to the panels is that okay?}
Behind Couch 6" thick
Wall behind speakers 6" thick (here some space between panel and wall is possible)
First reflection points on cealing 2"/4" thick
Cealing-Wall corner 2"/4"/6" thick (either back or front)

oh and some more general info:
the room height is 9ft; the shelves marked on the scetch are like built-ins from floor to cealing and very sturdy;
my speakers are hr824s;

At what point (i.e. after how many of these treatments) would I have to worry about the room going dead at high frequencies?
I don't really understand what the solution for that is, some sort of batting for the panels? Also would it maybe be a good idea
to put up a few broadband absorbers and then measure the frequency response and concentrate on isolateing weak-spots?
I presume that the frequency associated with 9ft will be a big weak spot for my room.

[Glenn Kuras]

Hey b17m4p,

Welcome to the forum..

Sounds like to me you are off to a good start on what you are thinking. The goal is to put as many bass traps in the corners as possible. But starting with the front and back corners floor to ceiling is great and may just do the trick. 6 inch for the bass traps are great and 2” or 4” panels for the first reflection should work fine.

"speakers would end up very close to the panels is that okay?}"

You should be fine

If you want to keep some life (high end) within the room I would face the bass traps (not the first reflection panels) with FRK. This will reflect the highs but absorb the lows.

Good luck on the room and happy listening!!

Glenn

PS I just built a listening room within my home (yea the studio just ain't enough ) and got the ACI speakers. The Mackie’s are cool, but if you ever upgrade you may want to look into them. They sound incredible..

[b17m4p]

Thanks a lot myfipie,

I guess my plan will be to start with the corner floor to ceiling panels, figure out how to test my frequency response with a mic, and then go from there.

Originally Posted by myfipie

PS I just built a listening room within my home (yea the studio just ain't enough ) and got the ACI speakers. The Mackie’s are cool, but if you ever upgrade you may want to look into them. They sound incredible..

I just recently got the Benchmark DAC1 so my wallet took quite a beating and I don't think I will be upgrading for a while. Besides especially for the size room I have right now I think the Mackies are just about perfect for me, I couldn't be more happy with them.

[No4PCs]

Originally Posted by xmostynx

here are the frames i built..


i went as cheap as possible with the wood...cojo was using (i think) 1x6

instead i used 1x2's to avoid cutting holes in them...here in pittsburgh a board of 1x6x4 was like 5 bucks..the 1x2x8's are only 1 dollar and change.

so the total cost of all the wood, to build 9 bass traps with the dimensions 2x4x8
was only

49.50


this is the first one...i have 8 more to go! going to walmart with this one to make sure i get the right amount of fabric to cover them

sorry for the shitty quality pic...i took it with my blackberry.
i'll take better ones with the digi later.

Hey friend, do you will close front and back with a plywood?
Or you will let open and front back free to sound?
What happens if i close the front panel with a piece of wood?
Thanks

[Scott R. Foster]

Originally Posted by b17m4p

snip

I would like to also attempt to build traps like these but I was hoping for some input on the best placement/ammount/etc.

snip

Here are the possible positions for panels. Which sholud I go for, in what priority order and in what thickness?:
Corners Behind Speakers 6" thick at 45 deg angle (cealing to floor yes/no) {speakers would end up very close to the panels is that okay?}
Behind Couch 6" thick
Wall behind speakers 6" thick (here some space between panel and wall is possible)
First reflection points on cealing 2"/4" thick
Cealing-Wall corner 2"/4"/6" thick (either back or front)

As Glenn explains, the corners are always a good start as porous absorbers get a performance boost in this location. Assuming you are using panels versus a wedge design like the SuperChunk

http://forum.studiotips.com/viewtopic.php?t=535

then you can further increase performance by mounting the panel across the diagonal of the corner, as shown below, assuring that when you mount the panels that the backside edges touch room boundaries [walls/floor/ceiling]. In essence, best practice is to NOT gap corner panels. Corner mounting without a gap produces a very broad Q resonance [about an octave] from +/- 60 to 120 Hz which happily falls in a part of the band typically beneficial to small room treatment [in acoustic, small rooms are anything smaller than a modest performance venue = less than +/- 7,000 cubic feet = 35x20x10'] and picks up just about where a normal sized [4 to 6" thick] porous absorber start to run out of effectiveness - toward the bottom of the frequency spectrum]. Such mounting extends and enhances the low frequency performance of your panels.

Then treat the first reflection points [front, side and rear]. Many find it beneficial to overdo the front end of the room in this part of the treatment plan as it tends to diminish SBIR and other forms of interference with the stereo image better than say the rear wall elements of treatment.

http://www.wsdg.com/dynamic.php5?id=.../taxi/computer

The reflection point treatment panels will typically be mounted against a flat surface and with these DO gap the panel. Generally, if you have the room to spare, it is best to leave a gap between the backside of the panel the room boundary = to the thickness of the panel - for a 4" panel, try for a 3 to 4" gap - more gap won't help much, but less and you are leaving free Sabines [the unit of measurement for acoustic absorption] on the table.

oh and some more general info:
the room height is 9ft; the shelves marked on the scetch are like built-ins from floor to cealing and very sturdy;
my speakers are hr824s;

Bookshelves you say... read up on the infamous Dope Traps?

http://gearslutz.com/board/showthrea...ght=dope+traps

I find the 824 passive woofer a bit anemic on the low end... and given the passive woofer fires to the rear, using them in tight corners near a bass traps may cuase additional LF problems that require tweaking of the rear panel settings. FWIW I have found adding a sub greatly boosts the usefulness of the 824... these units work well in this application:

http://www.partsexpress.com/pe/showd...number=300-760

At what point (i.e. after how many of these treatments) would I have to worry about the room going dead at high frequencies?
I don't really understand what the solution for that is, some sort of batting for the panels? Also would it maybe be a good idea
to put up a few broadband absorbers and then measure the frequency response and concentrate on isolateing weak-spots?
I presume that the frequency associated with 9ft will be a big weak spot for my room.

If you avoid adding strong / narrow band resonances to your treatment devices [stick to a broadband approach - build units that absorb at all frequencies] you can typically avoid having to consider such issues. In most small rooms the need for absorption and the space available limits your ability to over absorb lows so much you need not concern yourself with doing so. But, if you have fitted out the room with extensive finishes that are absorptive at only high frequency - such as carpet on the floors AND walls AND an acoustic ceiling grid with thin tiles - then masking your bass traps from HF absorption can be beneficial. Any easy way to do so is to add a thin poly film scrim [heavy weight 6 mil plastic film covering the front side - adhered around the edges only - left free to vibrate in the middle will still absorb bass well but reject most absorption over about 250 Hz].

Don't just focus on treatment... speaker placement and an eye to console / desk early reflections have an enormous effect on a critical listening stations, especially in small spaces.

http://www.wsdg.com/dynamic.php5?id=...smallroomshigh

And yes you are likely to have a hitch at about 63 Hz from that 9' dimension...

http://www.bobgolds.com/Mode/RoomModes.htm

but in a room this size you have very low modal density at the bottom of audible band, thus you are apt to have a number of peaks and dips below 125 hz... don't focus on one of them, try to improve the smoothness of the whole spectrum.. think broadband.



Good Luck... and remember, pics or it didn't happen.

[Scott R. Foster]

Originally Posted by No4PCs

Hey friend, do you will close front and back with a plywood?
Or you will let open and front back free to sound?
What happens if i close the front panel with a piece of wood?
Thanks

It resonates and you get a peak in the absorptive band at that resonance... above and below the resonance, absorption will be rejected.

Don't do this unless you have to.. and if you do, you MUST measure your device and its placement carefully in order to know what you have done. An un-upholstered [naked] panel of mineral fiber in a corner has resonances and the absorption curve is not flat... turning it into a resonate device with a panel makes it less flat. Unless you have the need to match a device to a particular frequency band this makes no sense. If you do have such a need it makes more sense to consider what is causing the need - and fix that flaw [if you can] - versus building a giant wooden badger tuned to your problem.

Pure resonante devices such as membrane absorbers and Helmholtz chambers, etcetera are tuned devices, and thus are touchy and small rooms do not have a diffuse reverberant field [you can't just build the device confident oit wil resonate precisely as you expect and then put the device anywhere in the room and get effective results]. Construction tolerances, placement and measurement are critical necessities when using a resonate device approach to treatment.

Leaving the panels off is cheaper, yields units that weigh less and are thus easy to install and adjust or move to another location, and makes for a unit that works better at all frequencies [a smoother absorption curve].

[Glenn Kuras]

Originally Posted by b17m4p

Thanks a lot myfipie,

I guess my plan will be to start with the corner floor to ceiling panels, figure out how to test my frequency response with a mic, and then go from there.



I just recently got the Benchmark DAC1 so my wallet took quite a beating and I don't think I will be upgrading for a while. Besides especially for the size room I have right now I think the Mackies are just about perfect for me, I couldn't be more happy with them.

Oh yea nothing wrong with the Mackies at all, but you should stop by some time and hear these ACIs

For testing your room check out http://www.hometheatershack.com/roomeq/

Glenn

[xmostynx]

lets see if i can put up the rest of the pics!


there you go guys! my room sounds great with just 2 up! got 7 more to go!

[Cojo]

Nice done!

[Ethan Winer]

Scott,

best practice is to NOT gap corner panels. Corner mounting without a gap produces a very broad Q resonance

Actually, it's exactly the opposite. Any mounting technique that creates a peak in the absorption by definition does so with a correspondingly higher Q. This same rule applies to all of electronics and indeed to all of physics for that matter.

--Ethan

[xmostynx]

Originally Posted by Cojo

Nice done!

thanks cojo! you where an amazing help and motivation for getting these in my room!

if we lived remotely close i'd buy you a few drinks!

[Cojo]

Originally Posted by xmostynx

thanks cojo! you where an amazing help and motivation for getting these in my room!

if we lived remotely close i'd buy you a few drinks!

[Scott R. Foster]

Originally Posted by xmostynx

...there you go guys! my room sounds great with just 2 up! got 7 more to go!

Nice.. I love the special crime fighting suit.

[Scott R. Foster]

Originally Posted by Ethan Winer

Actually, it's exactly the opposite. Any mounting technique that creates a peak in the absorption by definition does so with a correspondingly higher Q. This same rule applies to all of electronics and indeed to all of physics for that matter.

--Ethan

E. Winer:

No... you are confusing two different things.

The comment does not pertain to a comparison of the absorption curves of a gapped corner mounted panel and a non-gapped one..

Rather, it refers to the nature of the introduced increase in absorption in terms of its breadth across the band. The added absorption is NOT an extremely narrow effect over a small section of the frequency spectrum, but rather a more gentle increase across a fairly broad section of the spectrum.

[b17m4p]

Scott,

Thanks a lot for your very informative input. I will have to take some time to look over all the info you linked to; I very much appreciate you help.

And myfiepie thanks for the roomeq link! I really didn't wanna shell out $150 for the ETF software.

Yay freeware

[xmostynx]

Originally Posted by Scott R. Foster

Nice.. I love the special crime fighting suit.

hahaha

keeping my lungs clean man! they keep this whole thing going! living in pittsburgh, i figured i get enough shit in them just walking outside...

[Glenn Kuras]

Originally Posted by b17m4p

Scott,



And myfiepie thanks for the roomeq link! I really didn't wanna shell out $150 for the ETF software.

Yay freeware

Cool, let me know how it works out for you.

Glenn