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Room help: measuring and treating a vaulted ceiling room

sarumbear

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The main issue the OP reported is bad sound, and in a later post confirmed unclear dialogue. There's a speaker/room interaction we have to understand.
Please read the subject he put and then read again, again and again until you realise that the OP is asking about his room!
 

pozz

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Please read the subject he put and then read again, again and again until you realise that the OP is asking about his room!
Sure is. A lot goes into the room question outside of just treatment, though. The contextual things set the stage for the right answer.
 
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ripmixburn

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I posted this in the persian carpet thread as well, but for reference this is the view from usual the listening position. In the top left and right you can see where the tweeter could theoretically reflect directly if it dispersed enough.

As a temporary measure I put some thick upholstery foam above the rafters (not pictured) and it definitely improved the sound a lot. Can't wait to hear what a carpet can do.
 

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ripmixburn

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I ran Room EQ Wizard for the first time on my Mac last night. My goal is to learn how to use it so I can identify issues with my very challenging room and optimize placement of speakers and treatments for bass before I apply Anthem Room Correction in the Anthem receiver.

I have two different Anthem Room Correction System microphones which technically work. I don't have compatible calibration files, but is that necessary for subwoofer calibration?

I am just testing for 2.1 (Monitor Audio RS6 and RSW12) I had a lot of variables to play with.

@pozz kindly suggested I get the early reflections out of the way sooner by putting the speakers as close to the corners as possible.

Here is a roomstyler rendering of the room without all the mess of objects in the room. I do have a lot of sound absorbing objects in the room currently but have not measured before and after. Also the beams (pictured above) are not in the rendering.
rooms_48183872_attic-masculine-living-room.jpg

rooms_48183892_attic-masculine-living-room.jpg


I placed the microphone on the stand in the sweetspot facing the ceiling and did abotu 20 sweeps with the following variables:
  • Main speaker port plugs in/out (out seemed better, despite being close to the front wall)
  • Subwoofer volume (a little lower seemed better, I never know where it should be set to start)
  • Subwoofer polarity (180° was massively better despite manual suggesting otherwise for A/V LFE)
  • A/V subwoofer crossover (60Hz seemed better than full range, 80hz,100hz or 150hz)
With my original settings (port plugs in, 80hz crossover, 0° sub polarity), if my mic and measurements are to be trusted from one location, left and right looked like this:
left-right-before.jpg


Inverting the sub polarity made the largest impact with the 60hz null.
left-right-small-bass.jpg


Combined:
spl-10-200.jpg


And up to 20kHz there is a terrible null at 200Hz:
left-right-small-60hz.jpg


I have no idea how to read this kind:
wavelet.jpg


Some questions:
  • Should I be testing the sub in isolation? Do I just unplug my speakers to do that or can REW control only the sub via HDMI? I think the sub should be able to go lower than what's measuring.
  • Was inverting the sub polarity a mistake despite it looking good in my measurement?
  • Is my mic okay for at least some of the frequencies?
  • How can I know where to apply treatments? I do have about a dozen 2-inch thick 14x20" acoustic panels but no diffusers.
  • The main issue I experience is a diffused image, which I assume is from vaulted ceiling reflections. I could fit thin diffusers or absorbers but how do I know where and what kind?
  • I don't own an SPL meter, but could my iPhone work? I think I can connect the Anthem mic to it.
Any other measurement help is appreciated!
 
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ripmixburn

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I should that that this is where the sub is located. The mic was equidistant from the floorstanding speakers on where my ears usually are.
rooms_48188584_attic-masculine-living-room.jpg
 
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ripmixburn

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No takers? Would love to at least learn where I should be putting the 11 panels that I do own? (or how I can measure that myself to make that determination).
 

pozz

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  • Should I be testing the sub in isolation? Do I just unplug my speakers to do that or can REW control only the sub via HDMI? I think the sub should be able to go lower than what's measuring.
  • Was inverting the sub polarity a mistake despite it looking good in my measurement?
  • Is my mic okay for at least some of the frequencies?
  • How can I know where to apply treatments? I do have about a dozen 2-inch thick 14x20" acoustic panels but no diffusers.
  • The main issue I experience is a diffused image, which I assume is from vaulted ceiling reflections. I could fit thin diffusers or absorbers but how do I know where and what kind?
  • I don't own an SPL meter, but could my iPhone work? I think I can connect the Anthem mic to it.
There's a limited amount you can know with certainty without a calibrated measurement microphone.

The polarity inversion probably did good. You can test the result with a few tones.

Around 200Hz you have SBIR. If EQ is ineffective (usually some frequencies respond, while the majority don't) it can only be dealt with absorption.

Apply 6 panels each to the sloped side walls. See if they helps. If they help only a little, the problem is more fundamental. More and thicker absorption would be a solution, and so would better speakers, but neither of those options are cheap.

Have you tried rotating your setup 90 degrees so you're facing one of the sloped walls?
 
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ripmixburn

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There's a limited amount you can know with certainty without a calibrated measurement microphone.
Does that mean my Anthem Room Correction System mics aren't likely usable with REW for accurate measurement? One came with a calibration file (incompatible with REW) and the other did not.

The polarity inversion probably did good. You can test the result with a few tones.
OK, just by ear from the listening position I assume.

Around 200Hz you have SBIR. If EQ is ineffective (usually some frequencies respond, while the majority don't) it can only be dealt with absorption.
I did move the subwoofer around 4-5 foot on the long way, 2 feet into the room, angled it 45° and even put it on a 3 ft platform… the 200Hz suckout was pretty consistent and audible by ear from the sweet spot.

Apply 6 panels each to the sloped side walls. See if they helps. If they help only a little, the problem is more fundamental. More and thicker absorption would be a solution
It won't be easy temporarily getting anything on the sloped side walls, I'll likely have to screw something in… but I did balance some 3 inch foam at the first reflection point and it does seem help a lot. Trying to imagine a more permanent solution. Slanted gobo? The swedes make some cool round panels that wouldn't look too terrible.

and so would better speakers, but neither of those options are cheap.
It's not beyond the realm of possibility but it's a 5.1 set so I'd likely do the whole shebang. I think the Monitor Audio set is still appealing as a second hand purchase. And the amp was replaced with their warranty replacement unit (Hypex). Not free or cheap unfortunately.

Have you tried rotating your setup 90 degrees so you're facing one of the sloped walls?
Yes, but that definitely did not sound as good and perhaps because the speakers were so much closer together but I remember it being a lot less enjoyable.
 

pozz

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I did move the subwoofer around 4-5 foot on the long way, 2 feet into the room, angled it 45° and even put it on a 3 ft platform… the 200Hz suckout was pretty consistent and audible by ear from the sweet spot.
SBIR is to do with your towers, not your sub.
Does that mean my Anthem Room Correction System mics aren't likely usable with REW for accurate measurement? One came with a calibration file (incompatible with REW) and the other did not.
They are designed to be used with ARC and are likely cheaply produced, so will have some inaccuracy. Hard to say how much or where.
It won't be easy temporarily getting anything on the sloped side walls, I'll likely have to screw something in… but I did balance some 3 inch foam at the first reflection point and it does seem help a lot. Trying to imagine a more permanent solution. Slanted gobo? The swedes make some cool round panels that wouldn't look too terrible.
I think that's your ticket then. Foam is lightweight and could be easily mounted and remounted.
 

pozz

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I found Stereophile measurements for the RS6 speakers which claims that they are "actually maximally flat down to almost 40Hz". I assume it's the room or positioning.
It's neither. The Stereophile claim is based a limited range of quasi anechoic measurements which comprise a listening window average. For the RS6 the listening window is relatively ("maximally" is hyperbole) flat, which doesn't mean much when assessing a loudspeaker.
 
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ripmixburn

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SBIR is to do with your towers, not your sub.

I do have them closer to the front wall than recommended… I can take more measurements. I found this positioning was best for focusing the center image (done by ear, listening to mono music) but perhaps is causing the suckout.

I can test again in a few different spots with the sub off, thanks!
 

pozz

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do have them closer to the front wall than recommended… I can take more measurements.
Keep in mind that the sloped ceiling is way closer to the the speakers than in rectangular rooms. That extra oblique bounce is as heavy a contributer as the front wall.

Normally you can minimize SBIR with positioning but for the most part it's dealt with using low frequency absorption, like a diaphragm-type.
 
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ripmixburn

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Keep in mind that the sloped ceiling is way closer to the the speakers than in rectangular rooms. That extra oblique bounce is as heavy a contributer as the front wall.

Normally you can minimize SBIR with positioning but for the most part it's dealt with using low frequency absorption, like a diaphragm-type.
I was just reading about the “cornersorber” http://www.acousticgeometry.com/wp-...-Low-Frequency-Absorption-Using-Membranes.pdf

Not sure where i could fit one as when upright they would not be in a corner. Front and rear ceiling?
 

pozz

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I was just reading about the “cornersorber” http://www.acousticgeometry.com/wp-...-Low-Frequency-Absorption-Using-Membranes.pdf

Not sure where i could fit one as when upright they would not be in a corner. Front and rear ceiling?
For max effectiveness these kinds of absorbers have to be mounted directly against a surface.

You can try these on the front wall, with your speakers directly in front of them: http://www.economik.com/primacoustic/gotrap-studio-gobo/ (specs, but they have to be assembled and don't look great) or http://www.economik.com/primacoustic/fulltrap-broadband-absorber-and-bass-trap/ (specs) This will help with SBIR somewhat given that you still have the nearby slanted side walls.

For the other problem, diffusiveness, you can mount foam or fibreglass panels on the side walls using this kind of bracket: http://www.economik.com/primacoustic/impaler-surface/ It's light, so you can adjust positioning as you need.

Say 4 of the panel absorbers, that's around $2k, and then a set of foam or fibreglass panels, that's another $1k (you will need more than a few). Expensive given what your speakers cost.
 
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ripmixburn

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For max effectiveness these kinds of absorbers have to be mounted directly against a surface.

You can try these on the front wall, with your speakers directly in front of them: http://www.economik.com/primacoustic/gotrap-studio-gobo/ (specs, but they have to be assembled and don't look great) or http://www.economik.com/primacoustic/fulltrap-broadband-absorber-and-bass-trap/ (specs) This will help with SBIR somewhat given that you still have the nearby slanted side walls.

For the other problem, diffusiveness, you can mount foam or fibreglass panels on the side walls using this kind of bracket: http://www.economik.com/primacoustic/impaler-surface/ It's light, so you can adjust positioning as you need.

Say 4 of the panel absorbers, that's around $2k, and then a set of foam or fibreglass panels, that's another $1k (you will need more than a few). Expensive given what your speakers cost.
Thanks again! Yes, those are steep. I found a very affordable local manufacturer and am tempted. https://inityacoustics.com/

Also… https://www.soundcontrolacoustics.com/
 
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ripmixburn

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I didn't set the input levels exactly, but I did compare both generations of Anthem microphones and it looks like they are close until about 5khz. But I guess a UMIK is in my future if I want to get more serious.
1643240084871.png
 
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