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Post by ufx221 on Nov 23, 2022 18:19:40 GMT
I am renting a small room (Layout A) which I mix in, and have built four 2'x4'x6" rockwool broadband bass traps in the corners, which are standing halfway up the wall. The front wall is plaster I believe, and the backwall drywall. The ceiling is 8' in height, made of stone, and I can't easily install cloud panels (I'll likely put a rug down as the floor is reflective) Through testing, the bass traps definitely help, but there's a room resonance that's quite heavy around the 125Hz mark that I'm wanting to tame a little. There's definitely not enough traps in the room yet. I've been reading Ethan Winer's tutorials on room treatment and have a decent idea on the basics, but need some pointers.
Because the room is small (11.4'x8.9'x8') I understand the priority is thick broadband bass traps in the corners, rear wall and front wall. I also gather that some mid/high adsorbers at the first reflection points are good for imaging (ignoring the ceiling as I can't do those)
I'm considering moving my setup to the longest dimension of the room (11.4') to optimize my listening position. In Layout B I'll add a few mid/high adsorbers on the side walls to cover first reflections (in green), an extra basstrap on the rear wall (the front of the wardrobe) and a few smaller 16" wide basstraps behind the speakers (in orange) as I'm space-limited. I'm also covering the corner next to the door with a basstrap. The issue that I have is with the integrated wardrobe - it sticks out 2.4' into the room with sliding mirror doors, potentially causing weird nulls if I'm sitting halfway. It could still be worth doing as I usually leave it half open, allowing me to fill it with clothes and also benefit from the rear bass trap in front of it.
On paper B still looks to be worth doing because it gives me more wiggle room for the main listening position, and mitigates peaks and nulls.
I'd highly appreciate any feedback, thanks! 
Current Layout A:
Proposed layout B:
In the above, the mid/high adsorbers can be mounted on the right side wall easily (drywall) vs the plaster on other sidewall.
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Post by rock on Nov 24, 2022 14:30:31 GMT
Hi ufx, Great that you've read up and your plans are good. Yes, B is an improvement especially with the RFZ absorbers on the sides. Remember, if you gap absorbers a distance equal to the thickness lowers their efficacy one octave. Too bad you can't do a cloud. Absorbers behind the speakers are least effective there but probably won't hurt. If you want to see, run REW with and without them in place. The door corner, depending on clearances if any, is a spot for absorbers, one on the wall and one on the door OR a portable "roll around" bass trap you could position during mixes. The corner bass trap might not be as effective as the others because of the short 2.4' wall dimension and placed facing into the room might be as good, again, run REW. Overall your plan as drawn is good and the changes I point out may or may not make significant improvements. Here's the Amroc room mode calculator amcoustics.com/tools/amroc?l=11.4&w=8.9&h=8&ft=true&r60=0.6 Looks like that 125 Hz is the 2nd axial mode of short 8.9 wall to wall so gapping the wall absorbers or even using thicker 6" + gap will help here. Other than that, all the amroc data looks good for your room dimensions. |
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Post by ufx221 on Nov 24, 2022 16:28:14 GMT
Thanks for your response rock, that’s great.
Interesting point on gapping the sidewall adsorbers - do you mean spacing between the panels in this case, not the air gap behind them?
On bass trapping behind speakers, why would this be less effective? I can potentially put them elsewhere, like under my desk etc, but I’ll try comparing with REW too.
Cheers
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Post by Hexspa on Nov 24, 2022 17:07:00 GMT
most likely B for a few reasons:
1. you can add more absorption, as per your plan. With no cloud and stone walls, you're going to need all that you can get.
2. boundaries are further away, sides and rear. That's less reflection strength at LP. Every little bit counts.
3. you can try 20, 32, 38, and 45% lengthwise locations. 38 is good but try those as well in addition to wherever your voice sounds most natural in the room (my hack).
Corners are only good places for bass traps because they're acting on two or more modes at once plus you get an air gap. Most acousticians will tell you that the axial modes are the main problem so really, those are best treated on the flat surfaces. Your ideal absorber for 100Hz is about a 2.8' fluffy absorber. Of course, this is huge but with enough coverage, FRK, and ideal placement you can still get a good decay result. I've mentioned in another thread that the ideal absorber material-thickness brackets are 6" rigid, 12" safe n sound and 24" fluffy. You can gap each up to 1x with minimal penalty. The thickest absorber is best among these options.
At the end of the day, it's about what you want and are willing to do to get there. If you don't know any better then, for a home studio absorb everywhere with the greatest quantity of the above options you can. If you can do 2' with a 2' gap fluffy everywhere but the ceiling, that's your best choice (besides that you'd be smooshed). I see you're already using 6" rockwool of some kind so if that's what you're committed to as a material then so be it.
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Post by ufx221 on Nov 24, 2022 23:58:35 GMT
most likely B for a few reasons: 1. you can add more absorption, as per your plan. With no cloud and stone walls, you're going to need all that you can get. 2. boundaries are further away, sides and rear. That's less reflection strength at LP. Every little bit counts. 3. you can try 20, 32, 38, and 45% lengthwise locations. 38 is good but try those as well in addition to wherever your voice sounds most natural in the room (my hack). Corners are only good places for bass traps because they're acting on two or more modes at once plus you get an air gap. Most acousticians will tell you that the axial modes are the main problem so really, those are best treated on the flat surfaces. Your ideal absorber for 100Hz is about a 2.8' fluffy absorber. Of course, this is huge but with enough coverage, FRK, and ideal placement you can still get a good decay result. I've mentioned in another thread that the ideal absorber material-thickness brackets are 6" rigid, 12" safe n sound and 24" fluffy. You can gap each up to 1x with minimal penalty. The thickest absorber is best among these options. At the end of the day, it's about what you want and are willing to do to get there. If you don't know any better then, for a home studio absorb everywhere with the greatest quantity of the above options you can. If you can do 2' with a 2' gap fluffy everywhere but the ceiling, that's your best choice (besides that you'd be smooshed). I see you're already using 6" rockwool of some kind so if that's what you're committed to as a material then so be it. Thanks for your reply! I’m committed to using Rockwool SnS for now as that’s all I can get. After your responses I’m considering just building 2 big 32” wide, 48” high 6” traps for the side walls, which will have a 1.25” air gap because of the actual depth of the 1x8 wood. That should nicely tame any low frequency issues (the big problem in my room) and hopefully not deaden it too much? I reshuffled my room earlier and layout B already sounds way better, especially when moving away from the front wall around 50cm |
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Post by rock on Nov 26, 2022 15:25:15 GMT
Interesting point on gapping the sidewall adsorbers - do you mean spacing between the panels in this case, not the air gap behind them? On bass trapping behind speakers, why would this be less effective? I can potentially put them elsewhere, like under my desk etc, but I’ll try comparing with REW too. 1.) I think you are referring to this: "if you gap absorbers a distance equal to the thickness lowers their efficacy one octave." Here I mean the gap is the distance between the absorber and the wall (or other boundary). The primary reason for absorbers on the side walls is early reflections, but in your specific case, you note a resonant peak at 125Hz so I'm suggesting by using a thicker absorber and mounted (or positioned) an equal distance (gap) from the wall, you'll get more effective low end control with the same absorber. Regarding spacing between absorbers: You typically won't have complete 100% coverage (although you could) and therefore will want to spread a measured quantity of absorption over a given room or surface area after prioritizing specific areas like corners and RFZ. 2.) In general, the wall behind the speakers typically is an area that is not a problem and using resources in other places might give you more bang for the buck. It's not that they will be useless or undesirable there, so as Hexspa pointed out "you can add more absorption, as per your plan. With no cloud and stone walls, you're going to need all that you can get." I don't know if he was specifically referring to the absorbers behind the speakers but either way, I agree. Cheers |
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Post by ufx221 on Nov 30, 2022 6:02:26 GMT
Interesting point on gapping the sidewall adsorbers - do you mean spacing between the panels in this case, not the air gap behind them? On bass trapping behind speakers, why would this be less effective? I can potentially put them elsewhere, like under my desk etc, but I’ll try comparing with REW too. 1.) I think you are referring to this: "if you gap absorbers a distance equal to the thickness lowers their efficacy one octave." Here I mean the gap is the distance between the absorber and the wall (or other boundary). The primary reason for absorbers on the side walls is early reflections, but in your specific case, you note a resonant peak at 125Hz so I'm suggesting by using a thicker absorber and mounted (or positioned) an equal distance (gap) from the wall, you'll get more effective low end control with the same absorber. Regarding spacing between absorbers: You typically won't have complete 100% coverage (although you could) and therefore will want to spread a measured quantity of absorption over a given room or surface area after prioritizing specific areas like corners and RFZ. 2.) In general, the wall behind the speakers typically is an area that is not a problem and using resources in other places might give you more bang for the buck. It's not that they will be useless or undesirable there, so as Hexspa pointed out "you can add more absorption, as per your plan. With no cloud and stone walls, you're going to need all that you can get." I don't know if he was specifically referring to the absorbers behind the speakers but either way, I agree. Cheers
Here's the result (only taken an L+R result so far) from adding a few 32" traps on the side walls. I'm reasonably happy with the uniformity given no ceiling traps, but there's still a few troublesome spots:
-High peak at around 132Hz -Extended decay and loudness at lower frequencies (still have a bit of boomyness) -Slight null around 60Hz
Obviously more traps would be ideal, but I'm not sure I have the space! I could probably get away with one more on the rear wall, adding some clothes in my wardrobe and maybe chucking another under my desk
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Post by Hexspa on Jan 11, 2023 19:09:33 GMT
For waterfall, you don't really need anything above 300Hz. That ~140Hz ringing is from an 8' (or multiple) boundary. Your width is 8.9' and height 8' so I'm not surprised to see 140Hz (a little below) ringing. Luckily, that's your worst problem since you only need to focus above 63Hz. You can tame that with a 1' safe n sound panel with 1' gap on your width or ceiling boundary. Probably better to do the width. Remember that you can also EQ (down mostly) if you've exhausted your positioning and absorption options. Just be sure to take a few measurements in a reasonable radius to make sure you're not worsening problems elsewhere.
Sorry for the late reply. I must've meant to reply then never did it.
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