doing another bass trap build

[takman]

and you guys thought you were rid of me...hahaha!

So my friend liked my studio.. so im going to help him build his...

this is the sketchup i made....

what do you guys think??

Yes its a lot of panels...but every wall, the ceiling and floor are all conrcrete..so the room is really live.....and it might make the room a little dead...but we arent worried about it because my room is almost the same size as his with almost the same amount of panels....





the right side of his room is slanted, and has 3 wood beams sticking out...originally i was planning on mounting panels right on the face of the beams...but then i thought it might better to recess them inside...








also, i just realized a problem here...when i made my desk, i made it deep enough so that the face of my dual computer screens were flush with the speaker faces...but his desk isnt very deep, so the speakers are going to be firing at the back of the computer screens..any ideas of what can be done besides building a new desk? or moving the speakers wider and to the front..which will scew up the equilateral triangle configuration....

[PaulP]

Originally Posted by takman

and you guys thought you were rid of me...hahaha!

Nice of you to stick around though you'll probably be too busy making music
pretty soon. Wish I was that far along.

As to your sketches, I believe it would be best if your wall panels were not
facing each other. They should each face bare wall (except for the early
reflection panels).

also, i just realized a problem here...when i made my desk, i made it deep enough so that the face of my dual computer screens were flush with the speaker faces...but his desk isnt very deep, so the speakers are going to be firing at the back of the computer screens..any ideas of what can be done besides building a new desk? or moving the speakers wider and to the front..which will scew up the equilateral triangle configuration....

How about lifting the monitors up and have them firing down at you over
the screens ?

Paul P

[takman]

Originally Posted by PaulP

Nice of you to stick around though you'll probably be too busy making music
pretty soon. Wish I was that far along.

As to your sketches, I believe it would be best if your wall panels were not
facing each other. They should each face bare wall (except for the early
reflection panels).

How about lifting the monitors up and have them firing down at you over
the screens ?

Paul P

hmmm...ive never heard about the whole panel facing a bare wall thing...can you link me to something about that? I'd be to curious to read....every picture of studios i have seen with a panel setup like that have them facing each other.....

Would the middle reflection panel still be considered early? the thing is that its not going to work having opposing panels staggered/offset anyways...plus it wouldnt look good....im picky about symmetry...

if the monitors were lifted higher..they wouldnt be at ear level...im going to build him the exact same stands i have, which puts the tweeters at 1.2 meters...right at my ear level....could angle them...but it would have to be a pretty severe angle..

[PaulP]

Originally Posted by takman

hmmm...ive never heard about the whole panel facing a bare wall thing...can you link me to something about that? I'd be to curious to read....every picture of studios i have seen with a panel setup like that have them facing each other.....

The thing is parallel facing walls can produce standing waves. Panels
on both walls facing each other will take care of this but you'd need
them everywhere. Since you do want some reflections in the room
they can happen on bare wall patches opposite panels. Even better
would be to put diffusors opposite the panels.

im picky about symmetry...

I think acoustic symmetry is more important in the front part of the room
where you'll need opposite panels for the early reflections anyway. Visual
symmetry is another matter.

if the monitors were lifted higher..they wouldnt be at ear level...im going to build him the exact same stands i have, which puts the tweeters at 1.2 meters...right at my ear level....could angle them...but it would have to be a pretty severe angle..

I've seen lots of control rooms with the speakers above ear level, often
up by the ceiling. You have a serious difficulty with your two large screens,
something has to be done. Either lift or back up the screens or lift the
speakers.

Paul P

[Toni-P]

this is going to be intresting!

really liked the other thread you made on your own studio.


question tho, what do you use to make those sketches?

[Millo 3.1]

Toni-P:
it's a program by Google called SketchUp. Feel free to, mmm... "google" it. I need to learn it, these people are awesome at it.

[takman]

paul...i know what you are saying....

this build is going to be for a studio that will be upgraded later anyways....in 2 years max most likely....my friend plans on taking out a wall...completely re-doing the whole thing etc etc

by then ill have mastered REW, and we will get technical then.....same thing with my room...ill probably due a major make-over in a couple years...

I'll be taking a lot of pics....i know you guys like pics

[Arksun]

Originally Posted by PaulP

I've seen lots of control rooms with the speakers above ear level, often
up by the ceiling. You have a serious difficulty with your two large screens,
something has to be done. Either lift or back up the screens or lift the
speakers.

Paul P

The only problem with having monitors at a significant angle in a nearfield environment is that it does shrink the soundstage. I used to have my monitors firing upwards, but now I've got them on the level and the stereo placement seems much better. But then again my monitors are very near, (120cm per side equilateral triangle)

I'm wondering, if the line of fire is clear from speakers to listening position, could some treatment be placed right behind the screens?, like just putting a panel right behind them, or would that disrupt the wave patterns coming out the speakers a bit much?

[El-Roy]

When I put a panel behind my mixing desk it made a tremendous difference in the imaging. Everything just sounded so much more direct. Not to mention that it was the easiest to make and hang. Think I made it 6 ft wide x 4ft (basically from the ceiling to just below the bottoms of my monitors) and used 3 inch thick mineral wool.

[takman]

theres a window on the front wall that i didnt include in sketchup.....theres going to be thick curtain in front of it, to act like a panel....

edit: oops..just realized you said back wall...

[El-Roy]

Hey Takman, how thick of a curtain does it take to make a difference? Oh and I did mean behind the desk as in behind my monitors..though I also put 6" thick traps behind my mix position too. They both really made a difference.

One of the reasons I ask about the curtains is because here is my setup (I'll post some pics once I get a chance) I have 2 closets behind the mix position which I've taken the doors off of, mounted 4 2x4 6" inch traps approx. 4 inches off of the back wall (2 traps in each closet).. I just got curtains for curb appeal to cover the closets. I guess the question is do you or anyone on here think that having the curtains closed cancels out what I did with the bass traps in the closet or does it help it? Or maybe have no effect at all? I guess it's simple enough to just open them when I mix if that will be better.

All in all I think you guys will like what I did here, by opening the closets it added another 2 ft of length to the room. When I post the pics I'll do it on another thread...I don't mean to hi-jack yours takman.

[takman]

Originally Posted by tommcw

Hey Takman, how thick of a curtain does it take to make a difference? Oh and I did mean behind the desk as in behind my monitors..though I also put 6" thick traps behind my mix position too. They both really made a difference.

One of the reasons I ask about the curtains is because here is my setup (I'll post some pics once I get a chance) I have 2 closets behind the mix position which I've taken the doors off of, mounted 4 2x4 6" inch traps approx. 4 inches off of the back wall (2 traps in each closet).. I just got curtains for curb appeal to cover the closets. I guess the question is do you or anyone on here think that having the curtains closed cancels out what I did with the bass traps in the closet or does it help it? Or maybe have no effect at all? I guess it's simple enough to just open them when I mix if that will be better.

All in all I think you guys will like what I did here, by opening the closets it added another 2 ft of length to the room. When I post the pics I'll do it on another thread...I don't mean to hi-jack yours takman.

the thicker the curtain the better...a curtain with thin material would be better than nothing...

Its also good if the curtain has folds in it when extended...acts like a diffusor

I doubt the curtain over the closet it having any negative effects on your bass traps.....the Low frequencies will pass right through even a thick curtain...

[takman]

some pics...got more coming later....

the holes on the top triangle piece for the superchunks....as i was measuring his room for the chunks ( he has crown moulding like my room, so the chunks cant go all the way to the ceiling)....it occured to me that putting some holes on the top would add a little more absorption since there will be about a 6" gap between the top of the chunk and the ceiling/wall corner...

and YES the wall panels are pink

[takman]

and last but not least..the never ending cutting of the Rockwool

[Millo 3.1]

Awesome stuff, thanks for documenting your projects... Your threads have given me what I think are good ideas.

[takman]

heres what i got after shooting his untreated room....

one speaker (left)



one speaker ( right)



both speakers...

[Toni-P]

those speaker stands look very nice bro!

what kind of wood is it?

[takman]

Originally Posted by Toni-P

those speaker stands look very nice bro!

what kind of wood is it?

thanks....its the same design i built for mine, since i have same speakers as my friend...

1.6cm thickness...and i believe its called laminated particle board?

They will also be filled with sand like mine...weighing in at 75kg

[PaulP]

Also the "Impulse" response with the ETC and Schroeder integral checked and
the "Energy-Time" curve, expanded to show 0 to ~20ms (?), please.

Paul P

[takman]

Originally Posted by Victor_Stoian

please post the graphs unsmoothed (ev. 1/24) and scaled from 50 to 90dB.

[takman]

Originally Posted by PaulP

Also the "Impulse" response with the ETC and Schroeder integral checked and
the "Energy-Time" curve, expanded to show 0 to ~20ms (?), please.

Paul P

i checked the ETC and schroeder but im not sure about the energy curve to show 0-20ms? is this correct?

[M4-10]

I'm not sure if you've found a good solution for your computer monitors, but at my place I put my speakers and computer monitor on the edge of the desk closest to me, and my keyboard and mouse have a moveable stand on wheels (a keyboard tray mounted under the desk would have similar effect, although you might not be able to sit back enough).

Not only does the computer monitor not interfere with the speakers, but I don't get any comb filtering off the desk either. I was inspired to do that after I saw a picture of a mastering room that was basically contained a chair and 2 speakers.

[takman]

i have a couple questions about REW and other analyzing software....

this seems to be a popular analyzer..


Welcome to ETF Acoustics

how does REW compare to other software....?

if REW is the same or better as other software, then ill keep learning it...but if i can get better software that doesnt cost that much, i'd prefer to spend my time learning that...

also, when i check the levels on REW..i use 75 DB as recommended by the software and the people on hometheatershack......but i have to turn the channel volume on my microphone nearly to the point where i get that loud annoying feedback on the speakers before REW tells me the level is ok.....and actually, the volume knob for the mic is nearly maxed out too....Even though REW tells me the level is ok, i still cant get the output volume from REW and the input volume from the mic to match up.....

is this affecting my readings?

My soundcard is an m-audio fast track ultra...is it just a weak pre-amp in the soundcard? Or should i test at higher volumes..like 80-85DB? I'm using the recommended Behringer ECM8000 condenser mic...

[takman]

Originally Posted by PaulP

Also the "Impulse" response with the ETC and Schroeder integral checked and
the "Energy-Time" curve, expanded to show 0 to ~20ms (?), please.

Paul P

hows this?




im having a difficult time trying to understanding these graphs ( impulse, waterfall , spectral decay, RT60 etc etc) and information on the net seems sparse or hard to find.....can someone link me to good sites to read? or a good book?

[Lonely Raven]

I'm not any help as I'm still learning as well, but if you post your readings on HTS in the REW section, people who know better can probably guide you a bit. Maybe having someone read it for you will clue you in on how to read it yourself.

[PaulP]

If I were to hazard a guess... It looks like there's something happening at
5ms intervals. 5ms soundwise is 5.65 feet. Is your room 11.3 ft wide/long ?

Paul P

[PaulP]

I think this is worth a little bump...

Originally Posted by takman

A couple things.. I think it would be clearer if you removed the light-green
fill below the plot. Are both monitors sounding for this test ? I think it would
be best if only one monitor was used to make it easier to see which reflections
are coming from which speaker. Your microphone was at the listening position ?

If each peak is a reflection your first obvious one looks to be at about 1ms.
Is there anything a bit over a foot away from your monitor ? The next
largish reflection is at about 4ms or 5ft away. If both monitors were
active could this be from the other monitor ?

I think this is how you're supposed to use an ETC plot. Everything that
arrives at the listening position that is not the direct signal is a reflection
and shows up as a peak. For a reflection not to cause smearing of the
sound it has to be quite a bit lower in intensity than the direct signal
(it also can't arrive too late or you'll get an echo). You want as many of
these lower reflections as possible (a diffuse field) and you want them all
to decay exponentially in a reasonable amount of time.

I see in your case all reflections die down after about 400ms, which doesn't
seem so bad. My mostly empty untreated room goes on for 700ms (on the ETC,
the room itself continues to ring much longer than that).

Paul P

[takman]

paul...

I think it would be clearer if you removed the light-green
fill below the plot.

thats from checking the ETC box, which i believe you told me to do.

Are both monitors sounding for this test ?

nope...only one.

Your microphone was at the listening position ?

yep.

Is there anything a bit over a foot away from your monitor ?

this is the graph form my friends untreated room. only thing in his room would the desk, a sofa, and a couple pieces of small furniture. For this test i believe crouched under the desk when i hit start, so that i wouldnt be an equation in the readings...

I see in your case all reflections die down after about 400ms, which doesn't
seem so bad. My mostly empty untreated room goes on for 700ms (on the ETC,
the room itself continues to ring much longer than that).

but in the plot i posted where it shows time for over a second...it looks the same all the way through? like the peaks and dips continue past 1.37 seconds...






heres the impulse from my room....



setting correct?

[PaulP]

Originally Posted by takman

but in the plot i posted where it shows time for over a second...it looks the same all the way through? like the peaks and dips continue past 1.37 seconds...

I think the rest is just the noise floor, it's 60db down.

heres the impulse from my room....

Looks quite a bit better than your friend's. I'd stretch the plot out a bit
more horizontally to better see the peaks.

Paul P