# My audio room - how to make it better?



## Crossblade (Jul 21, 2010)

Hello guys!

I've been reading the forums (and especially this Acoustic sub-forum) for a few months now. However, it is just now I decided to post my questions here.

My room is rather small - 5x4.25x2.7m (16.4x14x8.85 feet) rectangular, with window on the front (4.25m) wall and a door in the back of the right wall.

I have treated it with broadband bass traps DIY made out of "fiberglass" - Rockwool Fasrock 50kg/m3. I've decided to treat it with bass traps, located at the walls/ceiling corners, four floor/walls corners and bigger panels for the early reflections on the left and right side.

I use my room primary for *stereo*, but I also have a surround system (center is behind the audio rack and two small surrounds are on the rear 2 panels on the side walls). It is 95% stereo, 5% surround. 

-----

Here are a couple of sketches, and then some explanations; _please note that I haven't drawn the basstraps/panels at the left part of the room, so everything can be previewed easier - they are symmetrically positioned. _

View from top: (click for bigger size)  | Angle view: (click for bigger size)
 


*wall/ceiling bass traps:* I didn't make super chunks, but rectangular "modules" attached at a slight distance from the ceiling and each other, to make a "pretty pattern" look. Each one is about 60x30x30cm (23.6x12x12 inches) big, and I have 17 of them - 6 on left side, 6 on right, 5 on back.
*floor basstraps:* I have total of 4 bass traps in the corners - two are 100x40x30cm (39x15.5x12 inches) and two are 100x20x30cm (39x8x12 inches) - the bigger ones are in the front right and back left corner, the smaller ones are in the front left and back right ones
*side panels:* For the early reflections I made total of 8 panels, 4 on each side, each with a size of 150x60x15cm (59x23.5x5.9"). Each one has 8cm/3.2" fiberglass only, but I added 7cm/2.7" air gap, to make it more effective.

I have carpet on the floor and nothing on the ceiling. I bought heavy curtains on the window, although I do not use them often.

-----

My speakers are backloaded horns with Fostex fullrange drivers. Their acoustic centers (speaker/horn mouth) are located 80cm (31.5") from front wall and 70cm (27.5") from side wall.

My seating position is a corner sofa located at almost exactly the center of the room - 2.55m (8.3 feet) or 51% from the front wall. I cannot move it forward, as it will get too close to front wall. If I move it backward (I can move 60cm/23.6" back to be at almost 38% from the back wall) I have to move my Audio Rack ( and my speakers ) closer, as my monitor is located on the rack and I must be at a close distance to be able to read it. However, my current measurements show that the 38% from the back wall is good on theory, but awful at my place.
---
So, here are the measurements at my current location - center width, 51% from front wall, speakers as explained:
*Waterfall:* 30Hz to 7.5KHz and 30Hz to 200Hz or 30Hz to 300Hz _- there is some difference in the last two, as they are taken in different days, so microphone/speaker position may be a bit off_
*SPL:* 30Hz to 7.5KHz, 30Hz to 200Hz and 30Hz to 7.5KHz smoothed
*RT60:* click to see

Also, here is a comparison of waterfalls at different position from the front wall (taken at the same day, same level) - it seems best is at 38% from the front wall (1.8m) and 1.95m, my position (2.55m = 51% from the front) has weaker lower bass and 38% from the back wall is awful. Unfortunately, I cannot position myself at the best position without compromise with my comfort.

*Waterfalls at different distance from front:* (name indicates distance from front wall)
1.80m = 38% | 1.95m | 2.10m | 2.30m | 2.55m = 51% = my position | 3.20m = 38% from back wall

_(For measurements I have used my Mac Mini and a RadioShack digital SPL meter)_

-----

So, can you suggest me what to do to make the situation at my seating position better? Should I treat the bare ceiling? Or as there is big difference front to back, should I treat front and/or back wall? 
Please, feel free to share your opinion on how to make this room acoustic better.

Hope that there will be enough people to read this (long) post and give me their input. I already know here are lots of guys that are really good at room acoustics 

Thank you in advance!
Nanko


----------



## bpape (Sep 14, 2006)

You're kind of between a rock and a hard place due to the monitor. Getting you in the 33-38% area will help smooth response. On the down side, the Fostex are going to like being a little closer to the walls for some reinforcement which you'll lose when you pull them out a bit. 

It will likely just be a tradeoff between smooth response and weaker deepest bass. The other option would be to add a sub so you're not counting on wall loading for the deep bass and from the Fostex.


----------



## Crossblade (Jul 21, 2010)

Bryan, thank you for the post! I hoped that you will see this thread.

I realize the monitor limits my options. However, I cannot remove it - I bought a big one (42") so I can stay at the computer (which I do nonstop) while being in the audio sweet spot, instead of having a separate desktop.

I will try how it sounds with the speakers closer to the wall. They will be pretty wide this way but we will see ... 
I do not corner load them, as when I tried it had powerful bass but not as detailed, and this way I cannot put the two bass traps in the corners .... 

Do you think I should treat the ceiling and the front/back walls to improve the situation? I guess ceiling treatment may kill some of the peaks and nulls due to height node, and front/back (or something else?) may help me make the sound at the listening position similar to the the sound at 38% from the front wall ... which is better. 

Nanko


----------



## bpape (Sep 14, 2006)

You don't need to corner load them to get boundary reinforcement. You can load them to the wall behind them but not in the corner. That just pushes the monitor farther to the wall to though and gets you even farther from optimal, unless you can get to 38% ish from the front wall?

I wouldn't do too much in terms of treatment until you pin down what the best compromise is for seating and speaker positioning.

Bryan


----------



## Crossblade (Jul 21, 2010)

Bryan,

I can move the speakers closer to the side walls. I will try it in an hour or so.
I cannot move them closer to the front wall as the right speaker will block the window from opening and I will have to move the whole "setup", which I do not like as an idea; in addition I will not be able to place the center behind the rack. 

I will post again soon, once I do measurement "now" and "after" moving the speakers closer to the side walls ... 

Nanko


----------



## bpape (Sep 14, 2006)

You can try that but with the rear loading of the cabinet and driver, the wall behind is a better choice - though closer to the side will change the SBIR which could be good or bad.

Bryan


----------



## Crossblade (Jul 21, 2010)

Bryan, as I said I cannot put them closer to front wall  

I moved them closer to the side walls:
Before:

_Strangely, the response looks different than before, probably due to slightly lower mic position. _
After:


Didn't get any low-end increase, still I think the bass now sounds slightly more powerful. Should listen to it for a while to see if there are any negatives.

---

Seems I cannot rearrange much ... any suggestions for additional treating ? What do you think about these graphs?  

Nanko


----------



## bpape (Sep 14, 2006)

Closer to the walls seems to smooth things a bit. Brings up a couple of dips and drops a couple of peaks. Not a lot, maybe 2db or so but noticeable. If you are comfortable with it moved, I'd leave it.

Overall, I think you're close to enough treatment in the room other than ceiling reflections and directly behind you but the furniture may not allow that.

Bryan


----------



## Crossblade (Jul 21, 2010)

Hey Bryan,

I think I will leave it this way, bass sounds better and I do not hear any defects in imaging for now.

I can treat the ceiling ... I am planning it. 
Would you recommend me how much to treat it? I plan on light absorption, 2" or max 4". Should I put panels at early reflections, or above my sitting position, or both? Maybe I can do some of them with semi-reflective surface (I should search for something like that here ...). 

As for the back wall, I have a huge wardrobe there, which is the only non-audio thing in the room (although I live in it!), and I cannot take it out .... I can treat the surface to the left and right from it. Any suggestions?

Thank you for all your posts, I really appreciate your help! 
Nanko


----------



## bpape (Sep 14, 2006)

Ceiling is high enough that you shouldn't need anything over your head. Just treat the reflection points. You can do either absorption or diffusion on those points.

The place I was referring to was behind you opposite the window where there appears to be a large cabinet in your drawing.

Bryan


----------



## Crossblade (Jul 21, 2010)

Thanks Bryan.

I will post once I have any progress...


----------

