Well now things get complicated

R

rsb

New member
I am working in a small room. I know I have a problem around 300hz.

If this was the space you had to work with would you make the sides live ( ie make them into Helmholz resonators ) or leave them dead? There is about 3" of 703 behind the cloth.

Thanks for any feedback.

Ryan
 

Attachments

  • front full.jpg
    front full.jpg
    39.7 KB · Views: 416
Ryan, if that room is as claustrophobic as it looks you wouldn't have space to put slats on the side walls, and they would probably cause some wierd early reflections even if you could. I'd probably mount the 703 stood off the wall by a couple inches if you can, making sure you cover any parts of both side walls where you could put a mirror and see either of your speakers in it. Then I'd use more to put a "cloud" over the mix area, and the rest at the rear of the room (stood off by several inches if possible, to get lower absorption frequencies)

If that's carpet on the floor, I'd (temporarily) cover it with plywood or (permanently) replace it with ANY reflective material (pergo, vinyl, etc)

You've got a good start with the flush mounting on your speakers, that in itself is helping the room a lot.

You might be able to do a slanted slot over the mix area that's tuned to 300, sort of like Son of Mixerman did - this would deflect early reflections to the rear to be absorbed, while taming the 300 hZ for you.

Have you determined where the 300 is coming from? If not, what are your room dimensions? I'd be glad to run them for you if it's not already been done... Steve
 
Your are the man

Thanks for the reply steve. The image I attached shows the dimensions of the room pretty accurately. This is what I built as well.

The whole ceiling is covered with 2" 703 with thin plastic and cloth over it. There are 3" over the desk and recording area in the back.

The back wall has 3 panel traps then 2" of 703 about a foot off the wall.

Thanks again for your feedback.

Ryan
 
ok one more time

Sorry this is so large. I tried to resize it but you could not see the dimentions.


Must have something to do with the gif format.

Oh well

Thanks again

Ryan
 

Attachments

  • final3.gif
    final3.gif
    16.6 KB · Views: 360
Can't tell anything by that drawing, Ryan - could you just post your dimensions, including height, as well as the distance from floor to the center of each driver on your speakers? Thanks... Steve
 
Will Do

I will get those measurements tonight.

Thanks again

Ryan


PS Any word back from John?
 
No word yet, I'll be "honey-do-ing" for a while but will check from time to time... Steve
 
Put your mouse over the drawing and wait for a button to appear over it in the lower righthand corner. This will scale it to 100%. Otherwise Internet Explorer scales picts to fit your browser window. Very legible to me here Steve. :)
 
Well, looking at your drawing, one big problem I see is that the 3" thick 703 on the side walls could be positioned better. You want to kill early reflections to improve stereo imaging. Right now, the 703 is so far back that 2 early reflections aren't being treated (shown in drawing for left speaker). So, move them forward as far as you can and I think you'd notice an improvement, especially considering the size of your room.

As far as the 300Hz problem, I'm not really sure what else you can do. You've got a lot of material in that room already that should be absorbing down to that frequency range and do you really want to make it any smaller? How do you know you have a problem there anyhow? You do RTA?
 

Attachments

  • final3.gif
    final3.gif
    18.7 KB · Views: 308
The reason for the 300hz issue was from previous calculations of the space. One coming from Ethans Mode calc and the other coming from the sae site.

I wodered if I should move those absobers forward or not.

The measurements of the soffit height etc are as follows:

Floor to center of woofer = 47.25"

Distance between woofers = 47.5"

Height from floor to 3" 703 = 77"

Distance from woofer to wall adjacent = 15"

Distance from center of front wall to 2" 703 off back wall = 13'

( Behind that back wall are 3 panel traps as I said before )

Distance between side walls = 73"

Thanks again for all your help.

Ryan
 
Ryan, I'm not seeing any axial modes at 300, do you remember which dimension was responsible? Or was it a null at 300? Steve
 
Unfortunately I do not. I had done the calculations before I started to build the treatments and had come up with the issue at 300hz.

So do you see any build up from the calculations you did?

Thanks again Steve.

Ryan
 
Not from just axial modes Ryan, but could you post your exact dimensions to actual walls/ceilings, as if the treatments weren't there? I'll run them through a full modal analysys to make sure Bonello distributions aren't skewed as well... Steve
 
sorry

Here are all the measurements. Thanks again Steve. I was on vacation.

Height 6.625'
Width 6.02'
Length 14.83'

I have a beem that runs the length of the room that comes down 6" on the left side and is 4.25" wide. I have covered it with 703 and cloth as well.

Thanks

Ryan
 
Ryan, I just ran your dim's thru two different sheets - one does all modes plus Bonello distribution graph, and the only problem area I see would be a LACK of modal activity around 50-80 hZ. There ARE several modes around 300, about 8 varied within 5 hZ, but only one is axial - the rest are tangential or oblique, and don't throw the Bonello curve off. Remember, the higher the frequency in a room, the more modes it can support.

Your room would tend to need a sub probably a bit more than average, in order to sound balanced.

Richhead, thanks for the reminder - sometimes I wish MicroSlop would quit trying to help us so much...

Ryan, I also agree with E-beam's suggestion to move the absorbent forward - your room is so small it almost needs to be absorbed as much as a vox booth, but it DEFINITELY doesn't need any early reflections messing things up... Steve
 
Thanks

Well I will move those absorbers forward and perhaps put some more insulation up.

The room is very dead. I had talked with John about using some peg board on the back wall. Any thoughts on that? Or should I just leave it?

Ryan
 
Ryan, with a room that small, dead is probably the best you can do - is the floor carpeted as well?

I think I'd start saving for a high end reverb box or a really good plug for whatever software you're running - keep in mind though, that with that dead a room you will tend to over-do any reverb. When you're making "transport-check" CD's, I'd make one with the verb level you like in the room, then cut it by 3 db at a time and re-burn - probably around -6 to -12 from what sounds good in the room will be what sounds good in other environments. Then, when you get close, you can do 1 dB steps to fine tune what works best... Steve
 
The floor is carpeted, it is just a shag on concrete.

I really appreciate your time with all this Steve.

It looks like I can put up the last treatments and start working!


Ryan
 
You must log in or register to reply here.
Back
Top