John Sayers' Recording Studio Design Forum

Hi dufo, unfortunately you're right... Do you know any possible solutions about that?

That's not ringing. It looks more like modes to me.

I'm looking at your SketchUp model, but it shows two rooms with no labels: one is rectangular and measures 4.1 x 2.2 x 2.6 m, and the other is not rectangular. Assuming that the control room is the rectangular one, the first two big peaks and the big dip on your graphs roughly correspond to the first three axial modes (1,0,0 - 0,1,0 - 0,0,1) at 42 Hz., 64 Hz., 78 Hz.

The dip at around 85 Hz and the peak at about 125 also match your 2,0,0 and 3,0,0 axial modes almost perfectly.

So it seems that you have large modal issues, especially along the room length axis. So you need heavy absorption on your rear wall, and large bass traps in the front and rear corners, both vertical and horizontal. The treatment you have in that room is nowhere near enough for a small room like that. I would put 6 inches (15cm) of 703 on the rear wall, spaced at least 15 cm away, and more if you can, plus full superchunks, floor to ceiling (36 inches (90 cm) across the diagonal face), in both rear corners and both front corners, then measure again to see what else needs doing.

Also, what type of foam is that? What are the acoustic characteristics? Please provide a link to the manufacturer's web site, so we can see what that stuff is.


- Stuart -

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I want this studio to amaze people. "That'll do" doesn't amaze people.

Thanks a lot for all your replies and hints.
I've attached another sketchup file where you can see my alternative idea, which is to invert the rooms and place the control room in the bigger one in order to gain space. It being understood that the acoustic treatment is needed anyway, do you think this might improve the quality of sound?

P.S. The foam is Auralex "Roominators Project 2 acoustic sound control kit"

I would not do that, no. The other room is not symmetrical, and the way you show it in that diagram, you have the speakers aiming across the room (short axis), instead of down the room (long axis). But even then, I still would not use that room as a control room, due to the lack of symmetry. It would be no better than the other one either, acoustically. It has similar issues.

Your solution is not about changing rooms: It is about installing the right treatment in the right places.

- Stuart -

_________________
I want this studio to amaze people. "That'll do" doesn't amaze people.

Ok! I’ll leave things as they are... Would you mind take a look at the pictures and tell me if I understood correctly? I would also like to know if is possible to fit the monitors inside the bass traps in order to gain space... Is there any other way to improve the acoustics without reducing the length of the room of 30 cm?
And what can I to correct acoustical problems in the not rectangular room?
Thank you!

Yes, that's about right. I guess the corner bass traps could be a bit smaller: They take up a lot of space like that. I had forgotten that your room is so narrow, so you could maybe make them only 60 or 70 cm across the front, instead of 90.

Also, if you are planning on mounting the speakers like that, then build proper soffits for them! You can use the bottom interior for bass trapping, using John's design for soffits.

- Stuart -

_________________
I want this studio to amaze people. "That'll do" doesn't amaze people.

Thank you very much for your reply!
What type of fiberglass or rockwool is better for works to be done? I found these:

Fiberglass:
15 kg/m3, 5 cm thick
15 kg/m3, 8 cm thick
17 kg/m3, 4.5 cm thick

Rock wool:
100 kg/m3, 4 cm thick
40 kg/m3, 5 cm thick
25 kg/m3, 10 cm thick


And what can I to correct acoustical problems in the not rectangular room? Excuse me if I insisted on it but a band will start recording soon and i would like to resolve its problems

I'm seriously thinking of making symmetric the live room to make it my control room ... sizes will become: 5.1 meters long, 2.23 wide and 2.66 meters high ... do you think that it would sound good with these dimensions?

I have finished the work of the two rooms, I made the long walls of the old live room parallel and the size of this room are now 5.1 meters long, 2.23 wide and 2.60 meters in height ... I have created, as suggested by Soundman2020, in every corner of the rooms superchunck of 71 cm of length face and for the old control room I've also done the other works recommended. I've attached the revised analysis files. I remind you that now the control room and live room are inverted ... for the use that I do of these environments I have opted for more space in the control room ...
Thanks to everyone who will want to comment!

Generally when making an overhead view in Sketchup (or any CAD program) you want to turn the 3D effect off (in Sketchup this would be clicking Parallel Projection on the camera menu).

It appears to me from your sketch, that your monitors are mounted at a very poor angle making the "sweet spot" somewhere over your desk as opposed to the usual LP. You need to change the angle of your front soffitwall/traps.

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Brian
As you slide down the bannister of life, may the splinters never point the wrong way...

Thanks BriHar for your reply!
You're right about the sketch, but in the end I opted for a simpler solution and I put my monitors on monitor stands... Nobody has comments about the analysis of the rooms after the changes?
I think there are still some issues in the control room at around 30 Hz where the T60 is about 700 ms ...

What speakers are you using (brand, model), and how did you set them up (position, angle, height, mounting)?

Photos would help.

- Stuart -

_________________
I want this studio to amaze people. "That'll do" doesn't amaze people.

Sorry, I'm not an expert in acoustics and I would like to better understand... the acoustics of the room should not be optimal regardless of the monitors and the position where I put them?

The acoustics will be different in different locations in the room, and the response of the room as a whole can change, depending on the position of the speakers.

For example, if you put a speaker in one of the corners of the room, then it will easily excite many (perhaps all) of the room modes, but if you put the speaker in a position that is a null for one or more nodes, then things will be very different.

The same happens with your listening position: as you move around the room, you will hear different things in different locations. If your head happens to be in the null for a certain frequency, then you will not hear that note or any of the harmonics of that note, or you will hear them at a much lower level. Or if your head happens to be at the location of a peak for a certain frequency, then you'll hear that frequency louder than it should be (and also all of its harmonics).

There are also other issues: if you put a speaker right against a wall, then you will get a boost in the bass levels, and you will also get comb filtering and other effects from the reflections coming off the wall, and the way they interact with the direct sound from the speaker. As you move the speaker away form the wall, you can easily hear the change in comb filtering moving down to lower and lower frequencies.

Etc.

That's why it is critical to set up your room correctly, and adjust the location of your listening position (your chair) and the locations of all of the speakers, for optimum results. There are general guidelines for setting up your room, based on percentages, angles, heights and distances: The normal way of optimizing is to set up the room like that, then make small changes to the positions of the chair and speakers, and see if you can get an improvement.

So it is also imperative to take the acoustic readings at the exact position where your head will be, and to carefully measure the location of the microphone that you use for the readings, so that you can get it back to the exact same position (accurate to within a half inch or so), for future readings, as you change the room treatment, or the position of the speakers. If you don't get the mic in the exact same place each time, then the readings are not valid and cannot be compared, since you are looking at a different part of the overall room response pattern.

So yes, a room can have great acoustics, but you'll could still hear different things in different locations around the room, since the sound waves are traveling around, interacting with the surfaces they encounter, and with each other.

It's complicated....


- Stuart -

_________________
I want this studio to amaze people. "That'll do" doesn't amaze people.

Thanks for your precious explanations Soundman2020 I'm sorry but I can not attach photos at this moment because I still have all disassembled in the control room... I have attached a sketch of my listening position with the respective positioning of my Yamaha hs 80 monitors...