Acoustics for 11'x13' Dedicated HT

[chinu_hark]

There is no treatment as of now. The sound is terrible and the bass is worse. I know the issue lies in the acoustics as the same speakers sound twice as good in other bigger rooms. My main issues are:
1) Boomy Bass (Horrible)
2) Listening Fatigue and harsh sound at high volumes (does not happen with same speakers in a bigger room).
Point 2 is what bothers me most as I just can't increase the volume to a reasonably good level without getting irritated in a few minutes. And I stress again that this only happens in this room.
It's a dedicated HT room (13'x11') with height 9.8' . Concrete Walls, Concrete Floor.



The window and door on the left wall go into a 10'x10'(approx) room and since these openings are relatively huge, it's sort of like 1 L-shaped room rather than 2.
I'm thinking about:
3xSuperchunk Corner traps as shown
1x4" Bass trap 4" from the wall below screen as shown
4 RFZ Panels as shown (2" at 1" from walls)
a) Should this give me an easily noticeable improvement and should I go ahead with this plan (Please suggest any changes if something's wrong)?
b) How much of an issue would the unsymmetrical treatments on the Left and Right walls be (The columns and the window are an issue) ?
c) What densities(fiberglass) should be used for the 3 types of traps/panels?
d) Kraft Paper, chart paper or thin cardboard as FRK?
Please help as I have zero experience about acoustics.

 

[chinu_hark]

Really? 60 views and no replies! Bump.

 

[sash]

My thoughts on this -
1. What speakers do you have? Are they rear or front ported? Towers or bookshelves?
2. I have made DIY panels and corner super chunks for my HT. I used a 2" thick 48 density fibreglass slabs for everything.
3. My panels do not have a hard front surface. I have wrapped fibreglass in thin foam and put them in a frame. I think high freq can give you a lot of fatigue and wanted to absorb as much of those as i could.
4. What ceiling do you have? Consider acoustic ceiling tiles from Anutone or Armstrong. Whatever you do DO NOT opt for light colored ceiling - if you put a PJ in that room, there will be a hell lot of light reflections from the ceiling.
5. Put the thickest carpet you can lay your hands on. This works magic.
6. Treating the walls behind the front speakers is very important. I haven't done much for the front wall but am planning on putting extra foam on it.
7. I have tried to document my experience here http://www.hifivision.com/av-enhanc...y-ht-room-acoustic-treatment-need-advice.html
8. Furniture helps dampen a lot of sound. If you are trying this in an empty room, put some furniture in there first.
9. Very thick curtain on doors and windows help a lot. Ensure there are lot of folds on the curtains and that they are extremely thick.
10. I'd try the carpet and thick curtain first and then move on to other improvements.

 

[giddavr]

Really? 60 views and no replies! Bump.

if u can wait till 16th, i will give u a detailed reply to turn ur room into a topclass home theater at minimal cost.

only saw ur post just now. but be assured u can have a great ht in there.

what we need to know is details of ur equipment

 

[sdurani]

Windows and doors are the ultimate absorbers, since nothing reflects off an opening. Problem is, you now have an asymmetrical soundstage with perfect absorbtion (openings) on your left and strong reflections on your right. So, at the very least, you should have broadband absorbtion the right side wall that is the size of the openings on the left side wall. This will give you symmetry as a starting point.

You can then add absorbtion across the front wall, which will help for a couple of reasons: 1) it will absorb reflections from your surround speakers, keeping those sounds in the surround field and prevent them being heard from in front of you (wrong direction), and 2) it will let you hear more of your L/C/R speakers and less reflections from that direction, resulting in greater intelligibility and articulation without unwanted reflections muddying up the soundstage. Covering the middle half or your back wall with absorbtion will similarly help.

If you are using a single subwoofer, move it to the midpoint of room width for smoother bass (should cancel your first room mode/standing wave). The midpoint of room width doesn't have to be on the front wall, it can be on the back wall or (my fave) right behind your sofa (nearfield bass means you hear more of your subwoofer and less of the room, resulting in much less boomy sound).

 

[chinu_hark]

Thank you for the well explained replies. Thinking of starting with left and right walls to bring some symmetry to the room. Will be building the 4 panels shown in pics. Confused between 32 and 48 kg/m3 for these broadband absorbers.

 

[sdurani]

For broadband absorption use the 48kg/m fiberglass in 4 inch thick panels placed 4 inches away from the wall. The air gap is one of the few times in acoustics where you get something for nothing. The 4 inch air gap will make the 4 inch panel 90% as effective as an 8 inch panel, since the sound has to go through it twice (which will really help make the bass less boomy).

 

[rdksrk2013]

For broadband absorption use the 48kg/m fiberglass in 4 inch thick panels placed 4 inches away from the wall. The air gap is one of the few times in acoustics where you get something for nothing. The 4 inch air gap will make the 4 inch panel 90% as effective as an 8 inch panel, since the sound has to go through it twice (which will really help make the bass less boomy).

sdurani@

Need to thank you for some important tit bits of info on acoustics regulary on this forum.:clapping:

Just out of curiosity - are you an expert in acoustics or have become an expert in the process of making your own HT?

 

[sdurani]

Just out of curiosity - are you an expert in acoustics or have become an expert in the process of making your own HT?

Just a hobbyist like you, but with an insatiable curiosity for how sound interacts with the room and how we humans hear those sounds. It has helped me when tuning my music room, allowing me to spend time making changes that result in an audible improvement rather than waste time on things I'll never be able to hear.

 

[chinu_hark]

OK, took a while, but it's done.
Cost for 7 bass traps and 3 RFZ panels : around 15000/-
Difference in sound : Priceless!
Bass is tight, sound is crystal clear and no harsh highs. I cannot express how much of a difference these have made. Everyone I show it to leaves extremely impressed. Dat Bass!
Important point I want to make is, there is no listening fatigue any more. Earlier, I just couldn't tolerate a volume level above 48 and after about 3-4 songs of loud listening I would stop, more often than not depressed by the whole experience. Now even at 55 it does not feel harsh, it's awesome actually. I can go on and on.
Various songs like Numb Encore, Ass like that, Yeah, Smack that etc to name a few (and practically every song by Green Day, LP and Avril) were absolutely unlistenable (no joke, I never listened to these as it was impossible) due to insane booms. Even turning the volume down to 40 and Sub to about -4dB, It was overall horrible. Now I can listen all these at 50 with bass at +4dB and they are actually the ones which sound the best. The detail in every single bass note, the drums, the stereo imaging are just so beautiful.
PS: Ignore some aesthetic issues. Front wall soon to be covered in black for Projector screen and AV rack and centre speaker yet to be painted.
Front

Front Top

Left

Sub Riser

Door Sound Proofing attempt (works quite well actually)

 

[neo9999]

chinu_hark - can you please tell me how did you fix the acoustic board to the door? I can see some hooks? did you place any ply behind the material and then hooked it to the door?

Neo

 

[chinu_hark]

The door has ply on the rear but it does'nt play any role in mounting. I don't remember the name but you get a small 2-3" metal strip with holes on regular intervals. Tell the hardware store guy 'latkane ke liye chahiye'. Put 2 screws through it, 1 into the door and the other into the panel.
Don't get your hopes too high about the sound proofing. I did it to use the remaining glasswool. Though it definitely reduces the sound, but not in a 'Sound PROOF' kind of way. In my case, the door was thicker than normal to begin with, final result allows me to listen at max tolerable levels inside during which sound going outside is not enough for the other people in the house to complain.

 

[audiohead]

im sorry to say but if you have bought those panels then that's a very bad job.

The panels are bulky and look ugly and besides you mentioned you bought all of them for 15000 INR? I wonder what the put inside cause the costing for just rock wool for so many panels would be about 10k and rock wool is not a good absorptive material, but now that you have already got them, i hope they are doing the job that you desired.