How I Treated My Ceiling For Immersive Audio

witchdoctor

witchdoctor

Full Audioholic
I have a 9.2.7 system and had a goal of getting the room to sound as close to a studio mixing stage as possible. I sent an e-mail to The Dub Stage https://www.thedubstage.com through their website and asked them for treatment suggestions. They responded back with a few questions and about my setup which is more in an Auro 3D style than straight Atmos. The owner of the Dub Stage copied the founder of Auro 3D, Wilfred Van Balen on his response and Wilfred followed up with me personally! Wilfred was very clear about treating ceiling reflections and managing bass. I thought about how to apply their recommendations as I wasn't able to put fiberglass panels or rock wool on my ceiling. Then I stumbled upon Gene and Anthony Grimani's series on youtube about room treatments and that helped a lot as for how to implement the advice I received. As for my height speakers I have 2 front height speakers and a center height channel mounted near the ceiling right above the corresponding bed channels. I have two speakers in the middle of the ceiling and facing straight down between my first and second row of seating. These speakers double as VOG for Auro and Top Middle for Atmos. Finally I have two rear height channels. My MLP sits the same distance from my front height speakers as my rear height speakers which are both angled toward the MLP. The front third of my room I placed acoustic panels made from polyester fiber that are white so they blend with the ceiling and light weight so I could affix them with alien tape.

The middle of the ceiling above the MLP and and in the back of the room off to the sides I used a pair of"geofusors" from Auralex , also very light so I could use alien tape. I filled the geofusors with polyfill so now they are a combo diffusor and bass trap. Wifred suggested having bass traps on the ceiling so this combo made it easy:


Finally Anthony Grimani suggested using diffusors on the ceiling near the back of the room. I borrowed the idea from the mixing stage of hanging an "acoustic cloud" of 4 Auralex Sustain Lens right behind the rear row of seats:


The end result was well worth the effort and many thanks to The Dub Stage, Wilfred, Anthony and Gene for their help.
 
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highfigh

highfigh

Audioholic Slumlord
My room isn't very big but that didn't stop it from having some problems that made me crazy- at my listening position, I could hear the difference in response when I moved my head to either side, only a few inches. If I sat in the 'wrong' position, I hated the low end and it really annoyed me. I decided to try using some panels I had made for a home theater that also had a large dip in the response around the same frequency and ran REW, to watch in real time as they might/might not help. They did and I haven't made any changes to the room since that time. I don't want or need 20Hz response (I did car audio for a long time and at times, super low frequencies can be annoying, to me) and the response is very smooth with the -3dB around 38Hz but excessive reflections and reverberation don't do the system/music any favors. I can feel the floor vibrating at times, even in a different room and that doesn't require extreme SPL.

I installed a small theater in the basement of an old house that has masonry foundation, mortered plaster on the walls and a Terrazzo floor. I walked in and said "Oh, my god!" when I heard the, let's call it 'ambience'. I measured the RT60 and the app showed that at some frequencies, it was as long as 6 seconds. The homeowner was all for treatments, then his wife entered the equation and 'they' (meaning 'she') decided to turn the theater area 90 degrees to the left, so I decided that it would be best to do what I could without arguing and trying to be pragmatic with people who don't actually care about acoustics. Fortunately, they had a large area rug and a huge pit group that absorbed the sound and prevented it reaching the back walls. It actually sounded pretty good.

I'm glad I took that acoustics class in college- it really helps to know what's happening and provides a good basis for solutions. Industry pros can be a great resource, too.
 
witchdoctor

witchdoctor

Full Audioholic
It is interesting how much difference moving the MLP can make even before you add treatment. I started with my MLP toward the back of the room, just like you see in the Dolby schematic for Atmos.


Wilfred Van Balen suggests that it is better to have the height speakers equidistant from the MLP. I moved my MLP forward into the room and measured both the distance and angles for not only the height channels but the angles of the L-R speakers as specified (30 to 22 degrees). That was HUGE and it was FREE, what a great combination.

The MLP is now much closer to this. I would recommend anyone setting up their room to follow this setup before doing anything else and its FREE to try.:
Atmos 2.JPG
 
witchdoctor

witchdoctor

Full Audioholic
I compromised on the "Top Middle" speaker position so they double as VOG. I brought the Top Middle pair closer together toward the center of the room, not in line with the height channels as shown in the above diagram and in between the first and second row. It works fine in both Auro and Atmos.
 
witchdoctor

witchdoctor

Full Audioholic
My room isn't very big but that didn't stop it from having some problems that made me crazy- at my listening position, I could hear the difference in response when I moved my head to either side, only a few inches. If I sat in the 'wrong' position, I hated the low end and it really annoyed me. I decided to try using some panels I had made for a home theater that also had a large dip in the response around the same frequency and ran REW, to watch in real time as they might/might not help. They did and I haven't made any changes to the room since that time. I don't want or need 20Hz response (I did car audio for a long time and at times, super low frequencies can be annoying, to me) and the response is very smooth with the -3dB around 38Hz but excessive reflections and reverberation don't do the system/music any favors. I can feel the floor vibrating at times, even in a different room and that doesn't require extreme SPL.

I installed a small theater in the basement of an old house that has masonry foundation, mortered plaster on the walls and a Terrazzo floor. I walked in and said "Oh, my god!" when I heard the, let's call it 'ambience'. I measured the RT60 and the app showed that at some frequencies, it was as long as 6 seconds. The homeowner was all for treatments, then his wife entered the equation and 'they' (meaning 'she') decided to turn the theater area 90 degrees to the left, so I decided that it would be best to do what I could without arguing and trying to be pragmatic with people who don't actually care about acoustics. Fortunately, they had a large area rug and a huge pit group that absorbed the sound and prevented it reaching the back walls. It actually sounded pretty good.

I'm glad I took that acoustics class in college- it really helps to know what's happening and provides a good basis for solutions. Industry pros can be a great resource, too.
Did you try moving your MLP yet?
 
lovinthehd

lovinthehd

Audioholic Jedi
Oh, come on, the actual acoustics matter little compared to the magic wires....tell us all about your magic wiring please.
 
witchdoctor

witchdoctor

Full Audioholic
Absorption Strategy for the Ceiling
Once I got the speakers and MLP setup dialed in for distance and angles with a laser pointer I had to select the type of treatment to use and where to place it. I started with the front third of the room between the front speakers and MLP. This area of the ceiling is getting sound reflections from both the L-C-R bed channels as well as the front height speakers. This is where I used absorption treatments. I had to take into consideration the weight of the panels, the color as I wanted the panels in white to match the ceiling, the ease of mounting them, and of course their acoustic performance. Fiberglass and rockwool were out because it was a challenge to mount on the ceiling, foam was out as most foam tiles aren't available in white so I checked out polyester fiber panels from Troy Studios available on Amazon (with a NRC noise reduction coefficient: 0.87. Average absorption coefficient: 0.77). I went with the small size tiles so I could be very precise with placement. I experimented placing with and without a 2 inch spacer between the tile and the ceiling. For my room no spacer worked better. I affixed the tiles with two sided Alien Tape very easily around the areas you see highlighted in yellow in the front of the room on this diagram:
Atmos ceiling 2.png
 
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witchdoctor

witchdoctor

Full Audioholic
Bass Trap Strategy for the Ceiling
Wilfred Van Balen suggested I use bass traps on the ceiling. That was a puzzle at first because bass traps are generally large. Auralex makes awesome foam bass traps which I could ceiling mount called Venus Bass traps but they didn't come in white:

Next I checked out one of their diffusors called a Geofusor which is a 3D diffusor that is extremely light and can be filled with polyfill so it can double as a bass trap. I mounted these right over the MLP and guests are shocked because it sounds like a speaker is mounted up there, they are so good at diffusing the sound and absorbing the bass once you fill them. I took a tip from Anthony Grimani when filling a panel with polyfill do NOT overfill, about half way works fine. If you only had ONE treatment to use on the ceiling I recommend this one. It can be used in a drop ceiling but I placed mine with two sided alien tape, just fine:
 
witchdoctor

witchdoctor

Full Audioholic
Diffusion Strategy for the Ceiling
When I watched Gene and Anthony's video on room treatment they suggested a strategy of using 2D diffusors in the front half of the room and 3D diffusors in the back half of the room. Anthony was kind enough to answer a question I sent him by email with a suggestion to use them toward the rear of the room. So I saw a photo of an Acoustic Cloud using Auralex Sustain Lens diffusors. These are made from bamboo and look great. Instead of the V-Shaped formation you see in this pic above a mixing desk I connected 4 of them together in a row, like a ladder. Auralex also sells a ceiling mounting kit and I did have to do some handiwork to get them mounted. They hang about 12 inches from the ceiling with enough room for my PJ to go between them and the ceiling which was an added benefit to kind of hide the PJ. This is NOT the configuration I used, but gives you an idea. They are mounted right behind my second row between it and the back of the room:
auralex-waveLens-diffusor.png

In this diagram the acoustic cloud is mounted where you see the yellow where the top rear speakers would have gone. It goes all the way across from where the TRL would be to where the TRR would be. I am using rear height speakers instead of TR speakers:
 
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witchdoctor

witchdoctor

Full Audioholic
In a nutshell, to get the MOST from immersive audio treat your room, but make sure to treat the ceiling. The ceiling is getting hit with the reflection from both your bed channel speakers as well as your height speakers. Before you stress about buying a new receiver or processor in search of a better room correction software treat your room, and don't forget your ceiling. If you did not yet watch Gene and Anthony's series on room treatment I would recommend starting there before buying anything:
 
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highfigh

highfigh

Audioholic Slumlord
It is interesting how much difference moving the MLP can make even before you add treatment. I started with my MLP toward the back of the room, just like you see in the Dolby schematic for Atmos.


Wilfred Van Balen suggests that it is better to have the height speakers equidistant from the MLP. I moved my MLP forward into the room and measured both the distance and angles for not only the height channels but the angles of the L-R speakers as specified (30 to 22 degrees). That was HUGE and it was FREE, what a great combination.

The MLP is now much closer to this. I would recommend anyone setting up their room to follow this setup before doing anything else and its FREE to try.:
View attachment 57377
The first thing I did was reposition my speakers and that helped, but I only moved them in small increments because the room really isn't large enough to go wild with everything. That helped a lot- small changes to the toe-in and distance to the back wall helped the overall sound, but the dips were still there. At that point, it was time to fire up REW and bring the panels in.
 
witchdoctor

witchdoctor

Full Audioholic
Can't move it- room size and shape don't allow it.
OK, so you have your seat and speakers dialed in as much as possible. I am not an acoustics expert but am happy to share what worked for me in my room. The first thing I did when ready to add treatments was add bass traps in the front corners. You have to consider aesthetics, the size of the trap, the material. In the front of my room I placed 1'x1'x2' foam bass traps from about 8 inches off the floor to almost the ceiling. They stacked nicely on top of one another and then I used alien tape to hold them in the corner. If you want them to look better than foam check out the bass traps sold by sonitus, much your attractive IMO. I only used bass traps in the front corners but it is similar to this digram:
corner-bass-trap-foundation.jpg


I also have a funny alcove that has corners I needed to treat. Here I just took the same absorptive panels I treated my wall with and mounted them kitty corner so it has a nice air gap behind it. You can get panels of various thickness depending on what you need.

Have you tried bass traps yet?
 
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highfigh

highfigh

Audioholic Slumlord
OK, so you have your seat and speakers dialed in as much as possible. I am not an acoustics expert but am happy to share what worked for me in my room. The first thing I did when ready to add treatments was add bass traps in the front corners. You have to consider aesthetics, the size of the trap, the material. In the front of my room I placed 1'x1'x2' foam bass traps from about 8 inches off the floor to almost the ceiling. They stacked nicely on top of one another and then I used alien tape to hold them in the corner. If you want them to look better than foam check out the bass traps sold by sonitus, much your attractive IMO. I only used bass traps in the front corners but it is similar to this digram:
View attachment 57394

I also have a funny alcove that has corners I needed to treat. Here I just took the same absorptive panels I treated my wall with and mounted them kitty corner so it has a nice air gap behind it. You can get panels of various thickness depending on what you need.

Have you tried bass traps yet?
My panels handled the problems- that part of the house opens into the kitchen on the side and has a hallway at the right rear, so some of the 'typical' room problems don't really exist. That doesn't mean it can't have issues, but it's less from standing waves and more from first reflections. I have several heavy, irregularly shaped items in the room, as well- those also help.

I used Owens Corning 703 panels- a couple are double thickness, the rest are single and all are backed by pegboard.
 
witchdoctor

witchdoctor

Full Audioholic
My panels handled the problems- that part of the house opens into the kitchen on the side and has a hallway at the right rear, so some of the 'typical' room problems don't really exist. That doesn't mean it can't have issues, but it's less from standing waves and more from first reflections. I have several heavy, irregularly shaped items in the room, as well- those also help.

I used Owens Corning 703 panels- a couple are double thickness, the rest are single and all are backed by pegboard.
Good, what type of preamp or integrated amp do you use? Does it have any EQ capability?
 
highfigh

highfigh

Audioholic Slumlord
Good, what type of preamp or integrated amp do you use? Does it have any EQ capability?
I'm using nothing that would be seen as 'high end' but it sounds very good. It has bass & treble controls, bass enhancement and some dynamics control but I don't use those. Somewhere, I have a file that shows the response from my main seat that's smooth, has a slight downward tilt and human voices are sometimes startling because they sound so natural- occasionally, I hear someone I know on TV or the radio and it's like they're in the same room.

I use EQ in systems that need it and only if they need it. I generally ask for input from the people who live with it, so I can make any adjustments needed.

I had one customer who asked if something could be done because his wife had problems hearing the dialog, so I tweaked the mids a bit and asked if it was too much for him- that worked, but the whole thing could have been avoided because she was a runner and used to wear a Walkman with ear buds, apparently at very high SPL and she had damaged her hearing. Since ear buds at the time produced mostly midrange, that was a death sentence for her ears. In a larger space like the school gym where I did an audio system upgrade, I used the EQ/crossover/limiting in the Crown power amp's DSP to smooth the response- full basketball court, hardwood floor, concrete walls and a stage at one end with a heavy curtain. The ceiling was wood grained pegboard that has fiberglass insulation above and combined with the way it was shaped, the reverberation wasn't bad- best gym I have worked in.
 
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witchdoctor

witchdoctor

Full Audioholic
I'm using nothing that would be seen as 'high end' but it sounds very good. It has bass & treble controls, bass enhancement and some dynamics control but I don't use those. Somewhere, I have a file that shows the response from my main seat that's smooth, has a slight downward tilt and human voices are sometimes startling because they sound so natural- occasionally, I hear someone I know on TV or the radio and it's like they're in the same room.

I use EQ in systems that need it and only if they need it. I generally ask for input from the people who live with it, so I can make any adjustments needed.

I had one customer who asked if something could be done because his wife had problems hearing the dialog, so I tweaked the mids a bit and asked if it was too much for him- that worked, but the whole thing could have been avoided because she was a runner and used to wear a Walkman with ear buds, apparently at very high SPL and she had damaged her hearing. Since ear buds at the time produced mostly midrange, that was a death sentence for her ears. In a larger space like the school gym where I did an audio system upgrade, I used the EQ/crossover/limiting in the Crown power amp's DSP to smooth the response- full basketball court, hardwood floor, concrete walls and a stage at one end with a heavy curtain. The ceiling was wood grained pegboard that has fiberglass insulation above and combined with the way it was shaped, the reverberation wasn't bad- best gym I have worked in.
OK, if you have your placement and treatment dialed in it seems that EQ would be the icing on the cake. I have a desktop system in an office with no treatment and use an integrated amp. Two desktop speakers and a sub. It sounds good but you can't help but notice the flutter echo and low volume listening can be a bit lifeless. I bought an integrated amp with room correction (ARC) from paradigm and WOW, it was like a whole new system. Wrapped in a bubble of sound. You have many products available that can provide this (miniDSP, DIRAC software if you connect a PC, NAD, Paradigm, etc). Do you NEED it. No. Does it help? I have three types of room correction in my various setups (Audyssey Pro, ARC, and AccuEQ). I would recommend it as a final step after all the other steps of speaker set up, MLP adjustment, and room treatment.
 

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