I have an 8ft ceiling which has around 3 inches of a reasonably dense Rockwool across it but I still notice a peak around 130-140Hz in my mixing position. The rest of my 16ft X 10ft room is also treated with superchunk corner bass traps and broadband absorbers all around. my question is:

Is it really possible to tame this frequency range in a room like this or am I kidding myself?

I would really appreciate any input. Thank you!

Yes it is definitely possible. How big is the peak? How big was it before you put your treatments in? If your treatments made things better, than you might just need more of them. Or if you didn't notice much difference, then you need better quality treatments.

You might also pay some attention to your setup, namely the listening position and the speaker position. Details here:
RealTraps - How To Set Up a Room

I didnt ever use my room without treatments so don't know but right now the peak is around 5db. I have my speakers set up like it says in the GIK videos as my room is around that size. Problem is I dont see how I can put more treatments on the ceiling and it seems that that is where the problem is. Rockwool is kinda heavy and when I put the cloud up it weighed more than I was comfortable with. Also the fact that the length of my room is twice the height makes it worse. If purchasing a trap for the ceiling would get rid of the peak I would defintely purchase one but I dont know that the treatment companies can guarantee such things.

jhb,

See the attachment. The room boundaries are causing you problems. IMHO, you would be better off in another room or resizing this room to suit better mode distribution.

You have coincidental resonances beginning at 70.6 Hz, 90.4 Hz, 133.2 Hz, 141.2 Hz, 152.1 Hz, 158 Hz, 168 Hz, 176.5 Hz, 180, 182, 183.6, 185., 194....

THAT'S your problem!

I wouldn't try to treat that. I'd fix it first.

Cheers,
John

Oh Boy. Here we go again !
I just hope he takes ur advice seriously, unlike what I did with the same kind of issues. Took a loooong learning curve, only to arrive at what u had predicted !

Yes that is what I figured. I went onto this site

Frequencies of Musical Notes, A4 = 440 Hz

which gives you the wavelengths and I could see that the louder parts coincide with the wavelengths. Unfotunately I cant do any building work and am stuck with what I have. Funny thing happened today though. I put a rug / carpet in and it reduced it a lot. It wasn't thick really just around half an inch or so. I thought carpets weren't supposed to provide any kind of absorption at those frequencies? Anyway, it helped but not as much as I would like.

Honestly that is not all that much if the rest of the FR is within +/-5 db or so. I would focus more on the decay of that area vs the frequency response. And yes you can treat that without a problem. See the following on decay times.
Understanding Decay Time and Waterfall Graphs - GIK Acoustics

Yeah, as John says that peak is caused by your room dimensions. 5dB isn't horrible....

If you can't add more treatment, then your options are to either upgrade your treatments or experiment more with setup. See if moving your listening position and/or your speaker position can get you a flatter response.

Details here: RealTraps - How To Set Up a Room
You might also take a look at the distance between your speakers and nearby reflective surfaces (such as the front wall). This is probably not the primary culprit but by experimenting with different placements you might be able to make some improvements.

Honestly I would first test the room to see if it is due to the height. If so then focus on the ceiling as moving the speakers/mix spot won't solve it. Moving the speakers will help with SBIR IF that is the problem. For testing see the following problem
Room EQ Wizard Tutorial - GIK Acoustics
About SBIR - Speaker Boundary Interference Response SBIR GIK Acoustics

Yep, could be the height as well, which is why I said nearby reflective surfaces. Try adjusting the height of the speakers as well and see if you get an improvement.

Bottom line it's a tough room, but since you are stuck with it it will be worth spending time to maximize the sonic potential of the room.

Plus one for sure!

IM CURED!

I added another layer of yellow fluffy fiberglass. This guy was throwing someout around the corner and he let me have it so I added it onto my cloud trap above my mix position. The results were incredible. Since the yellow fluffy was light I wasnt worried so much about the weight and I just stapled it over my original structure with fabric. from 100Hz up it is smooth sailing over here

Could it be that the rockwool I had in my cloud was either too thin (3" + 2" airgap) or perhaps it was not as good as this lower density fiberglass I added? The Rockwool is 70Kg m3 so around this forum that seemed to be a good density.

Thanks. I get the whole waterfall concept but my speakers are ported and that means the low end decay times are not accurate. Should I still test?

HAHA this keeps getting better and better. Even the 60Hz problem is gone

My frecuency response seems smooth from 55 Hz up

am so happy now!! Yellow fluffy saved me

Them being ported should not make a difference. Yes you still want to test.

Ok but do you think I could do the test with a cardioid mic? I dont have an omni :(

Hello, everyone. I find myself have a problem with 185hz. It's bugging the hell out of me.

I have a sloped cieling. Behind me it starts at 9 ft. 3 inches and drops to the front of the room (where I'm set up to listen) at 7ft. 3 1/2 inches.

The length of my room is 12 ft. 3 inches. The width is 8 ft. 10 inches.

I walked around with a sine wave at 185hz....it peaks very badly only if a few spots.

Not sure where to go from here to get rid of the problem.

Currently, I have my speakers set up centered width wise and my listening position is roughly the 38% I've read about. I have boxes full of blankets in the front right corner and the back right corner. They're from the floor to almost the ceiling. After doing this, it helped quite a bit, but of course there's still issues. I've yet to treat my first reflection points. I will be making some of my own ASAP to treat those.

How do I go about treating this 185hz problem?

Any advice or comments are greatly appreciated and thank you in advance.

Because of the dimensions and where you sit, you have a stack of axial,oblique and tangent action there.

To attack it you can do 2 things:

1) Find a better position for speakers and sweetspot

2) Trap the corners between front wall and ceiling, backwall and ceiling, floor and front wall and floor and backwall.

The strongest are the 4-0-0 axial because of the front and backwall and the 0-0-3 axial mode from ceiling. If you aren't going to trap the entire back/ front wall and ceiling, try the corners that connect them first.

I'll take option 2.

Thank you.

I assume they'll have to be around 4 inches thick? I'm thinking 2X2 panels that are 4 inch thick in each corner.

Thanks, again for the reply.