holdingpants01
Major Contributor
- Joined
- Mar 18, 2023
- Messages
- 1,063
- Likes
- 1,803
20cm ceiling absorption in a 2,2m room? I hope the OP is not tall or doesn't have claustrophobia
-
Welcome to ASR. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!
7.1.4 setup, Genelec vs KEF
- Thread starter Keksstein
- Start date
A 10-20cm ceiling absorber doesn't help with bass resonances at all! I have my complete ceilings in some rooms absorptive from 8cm (office), 16cm in the recording room to 20cm BCA absorbers (listening room). I have 40-60cm absorption in the back of my listening room and there are still resonances in that direction (but good controlled and broadband, no excessive rt60).
You can use RWE to calculate what's needed to get rid of bass resonances - it's very hard to build absorbers which can do that, esp in a small room.
But you only need to get absorption right down to 80Hz when you use a DBA for low frequencies ... and with a fixed seating row you get away with SBA too.
You can use RWE to calculate what's needed to get rid of bass resonances - it's very hard to build absorbers which can do that, esp in a small room.
But you only need to get absorption right down to 80Hz when you use a DBA for low frequencies ... and with a fixed seating row you get away with SBA too.
More is always better but 10cm should be fine too.
From all surfaces the ceiling is the most important that needs absorption because of the shorter paths.
Ceiling reflections also don’t really add anything desirable to the sound stage
From all surfaces the ceiling is the most important that needs absorption because of the shorter paths.
Ceiling reflections also don’t really add anything desirable to the sound stage
That’s why I advised to build a SBA or DBA. That will eliminate all bass resonances. The ceiling absorption is only needed to get rid of those very short early reflections
You can't do magic - it's physics.
Have a look what 10cm of absorption do. I always say it's a minimum for music but for a serious room ... there is more or less nothing happening <100Hz.
You need more advanced absorber tech in such a room combined with some good speaker technology and room adaption ... not easy but it's doable.
holdingpants01
Major Contributor
- Joined
- Mar 18, 2023
- Messages
- 1,063
- Likes
- 1,803
That's what I'm saying, outside of physics there's also equally important visual side, this is suppose to be fun room and hanging 20cm of wool above the head for doubtful benefit is not fun. In the world where Dirac ART exist I probably wouldn't waste the space on any bass trapping, but that would've to be measured (science, physics)
A can-do attitude like yours surely helps. Is it enough, though?!
The youtube guy puts it quite nicely as ~"by the time you fixed acoustic issues in a small room, you cannot enter it anymore". The nice absorber calculator you posted only confirms: 10cm is useless under 100Hz, 20cm does very little and more is physically impossible. AFAICS, the absorbtion-fix is case-closed.
A 2BA/multiBA setup will help. Hard to say how much but I seriously doubt it'll be anywhere near enough.
L-C-R speakers with narrow vertical directivity may be a better choice (and my KEF triaxials recommendation does not look so good anymore).
And the last & (probably) best hope is room-dsp: trinnov/dirac/acourate/etc...
How much will all the above bring is anyone's guess.
The way I see it: excellent/20-20 sound seems impossible and good sound is a maybe. And my main question is (still): how much time/effort/money is worth investing under such circumstances ?!
P.S.
amroc seems to be the room modes calculator shown in the youtube videos. Better don't look at it
Last edited:
I did rooms with 2,3-2,4m height - so I don't have to guess. 
You can't get a great live acoustic sound but a great controlled acoustic. And 20cm absorption at the ceiling is not "doubtful" - it totally transorms your room! Have you ever tried that? Entering such a room is already fun! (OK, I'm probably a little more geeky as sound enginer about this topic as most people ... 
)
You can do broadband compact absorbers in 10cm thickness (but I prefere to give them a little more). It's a little tricky to mount them at the ceiling when DIY, walls are easy. And they go past 100Hz.
A proper double bass array SOLVES the LF issues in your room. Even a single bass array can be enough, depending on the rest of the setup.
And no - DSP is NOT the best bet to fix a room ... it's the iceing to linearise the rest. You can't fix higher frequency bouncing and reflections - it's very quickly very chaotic in an untreated room! (Did you ever calculated/simulated how many reflections you get in the first 10ms with a 7.1 system?) But 10-15cm absorption helps with that (and at walls and corners more is easily possible).
20-80Hz - bass array
80-200Hz - speaker placement (SBIR etc)
100-20kHz - Absorption
Visual side - that's a matter of priorities and design. A well dampened room FEELS GREAT! That's part of the experience, to enter a silent and cosy room and get prepared for a nice film. An acoustic ceiling can be just plain white fabric - some cm deeper as the original ceiling (or dark -> cinema). You can put lights in it and hide whatever you want.
You can also do a wooden framed design what I plan in my living room to fit the rest. You don't need the whole room down with 20cm, corners work best etc.... so many possibilities.
But one thing is for sure - if you do NOTHING at the ceiling good sound is not even a maybe ...
Dirac ART - you only can correct frequencies ALL your speakers are able to play. So you would need 7+4 Speakers which go down to 20-30Hz in cinema level. Cause when one speaker has to chancell the wave it doesn't add to the SPL level, it even kills it. (Like a DBA - you need WAY more speakers cause the 2nd array doesn't add SPL and you have no resonances which give loudness)
So think about these costs ... you can build plenty of acoustic stuff for that money.
You need a SYSTEM for a small room cause the mechansims need to work perfectly together. I did it for my listening room and it works. And I did a few small recording rooms which also work very well (with a less dampened acoustic but still no "boxy" sound of a small room).
You can't get a great live acoustic sound but a great controlled acoustic. And 20cm absorption at the ceiling is not "doubtful" - it totally transorms your room! Have you ever tried that? Entering such a room is already fun! (OK, I'm probably a little more geeky as sound enginer about this topic as most people ... )You can do broadband compact absorbers in 10cm thickness (but I prefere to give them a little more). It's a little tricky to mount them at the ceiling when DIY, walls are easy. And they go past 100Hz.
A proper double bass array SOLVES the LF issues in your room. Even a single bass array can be enough, depending on the rest of the setup.
And no - DSP is NOT the best bet to fix a room ... it's the iceing to linearise the rest. You can't fix higher frequency bouncing and reflections - it's very quickly very chaotic in an untreated room! (Did you ever calculated/simulated how many reflections you get in the first 10ms with a 7.1 system?) But 10-15cm absorption helps with that (and at walls and corners more is easily possible).
20-80Hz - bass array
80-200Hz - speaker placement (SBIR etc)
100-20kHz - Absorption
Visual side - that's a matter of priorities and design. A well dampened room FEELS GREAT! That's part of the experience, to enter a silent and cosy room and get prepared for a nice film. An acoustic ceiling can be just plain white fabric - some cm deeper as the original ceiling (or dark -> cinema). You can put lights in it and hide whatever you want.
You can also do a wooden framed design what I plan in my living room to fit the rest. You don't need the whole room down with 20cm, corners work best etc.... so many possibilities.
But one thing is for sure - if you do NOTHING at the ceiling good sound is not even a maybe ...
Dirac ART - you only can correct frequencies ALL your speakers are able to play. So you would need 7+4 Speakers which go down to 20-30Hz in cinema level. Cause when one speaker has to chancell the wave it doesn't add to the SPL level, it even kills it. (Like a DBA - you need WAY more speakers cause the 2nd array doesn't add SPL and you have no resonances which give loudness)
So think about these costs ... you can build plenty of acoustic stuff for that money.
You need a SYSTEM for a small room cause the mechansims need to work perfectly together. I did it for my listening room and it works. And I did a few small recording rooms which also work very well (with a less dampened acoustic but still no "boxy" sound of a small room).
holdingpants01
Major Contributor
- Joined
- Mar 18, 2023
- Messages
- 1,063
- Likes
- 1,803
This is too much text to parse, but briefly: I did quite a lot of rooms in my career, right now I'm sitting in a smallish 20m2 control room with treated ceiling, and mostly just ceiling because it's high enough to do it, so it doesn't feel like something is falling on my head and I like to see the walls (they're made from raw brick). It's an atmos setup BTW.I did rooms with 2,3-2,4m height - so I don't have to guess.
I didn't say anything about DSP, I said that for the low end Dirac ART will be more efficient than any passive bass traps realistically would. The OP already said he would built 4 big subwoofers so there's no worry about the headroom, but the needed power for that is way overblown by you, my PSI Audio Avaa C20 consume 70W at maximum while absorbing even below 20Hz.
Visual side I meant taking out 20cm out of 2,2m room, if you like to be in a room where you touch the ceiling with your hand slightly up, then fine, most people wouldn't and I'm not. 10cm would work almost the same if you use walls for absorbtion. It's also not nearly as important with tighter directivity monitors, like the Genelecs he consider and I also use.
I don't want to take over this thread as the OP already knows what to do, so let's not go further with that
Last edited:
No practical experience here, I actually gave up on a similar room/idea. The theory/graphs were too discouraging: 10cm does ~nothing below 100Hz and 20cm ~nothing below 50Hz. Also, with 20cm of ceiling absorbtion in a 2.2m room, the sound may not matter much anymore - I probably won't like spending time in there.I did rooms with 2,3-2,4m height - so I don't have to guess.
...
But that's just my view... and I only have theory and you say that you worked with similar rooms ... so there's that
Hope you guys find some solutions and wish you good luck!
P.S.
Progress reports and more info about similar rooms would be highly welcome. A few clear measurements may change my mind about those 'standard' 2.2 - 2.5m basements.
holdingpants01
Major Contributor
- Joined
- Mar 18, 2023
- Messages
- 1,063
- Likes
- 1,803
You can watch this guy: https://www.youtube.com/@AcousticsInsider he believes in as much absorption as possible in small rooms and provides measurements of finished rooms.No practical experience here, I actually gave up on a similar room/idea. The theory/graphs were too discouraging: 10cm does ~nothing below 100Hz and 20cm ~nothing below 50Hz. Also, with 20cm of ceiling absorbtion in a 2.2m room, the sound may not matter much anymore - I probably won't like spending time in there.
But that's just my view... and I only have theory and you say that you worked with similar rooms ... so there's that
Hope you guys find some solutions and wish you good luck!
P.S.
Progress reports and more info about similar rooms would be highly welcome. A few clear measurements may change my mind about those 'standard' 2.2 - 2.5m basements.
To put things into the perspective, minimal legal height of a flat in my country is 2,5m. The 2,2m is the minimum limit in a places where a person can be only temporarily and doing only specific jobs, like a security booth. For living, learning or recreation it is 2,5m at minimum. Those are health related limits, I would seriously reconsider building anything there
Thx for the youtube channel, looks interesting.
AFAIK, 2.5m height is the legal limit EU-wide, may even be worldwide. I moved around a lot and I'd take 3+ meters anytime .. much, much better and not only for sound.
But there seem to be no rules for basement-rooms and 2.1-2.3m seems to be the EU usual. Also asked a house builder and they were a bit baffled: only 2.2m & 2.45m as standard-offers and anything above "should be possible but quite expensive".
@cyjanopan To much text to read? 
My office is 2.20 after ceiling treatment, my listening room also. I don't think that's a serious health issue, I'm SITTING all day in these rooms and feel fine
.
When planning a room for audio 2.20 is of course a no go. But when it's the only option ... you have to make it work. 2.20 is a cave anyways... (I loved to live in 3.3-3.5m rooms, you find them in Vienna. But you need a lot of treatment also - don't forget this >1m up there!)
Just a few measurements of my non environment room. 16cm BCA absorption on the ceiling, 16cm on 3 walls and a lot of additional absorption as moveable absorber walls in the back. Ready ceiling after floating floor and ceiling treatment 2.2m.
That's NOT THE RIGHT GOAL for a home cinema room! That's what you CAN achieve with not too fancy acoustic work.
But you can't let rt60 of 0,4s in such a small room, these guidelines are for much bigger rooms.
For recording rooms I like to do a ring around the ceiling/wall corner with deeper absorbers and fit the rest of the ceiling to the situation/reflection points. But with a low ceiling you need absorption in areas where microphones are. At least one wall completely absorptive (to get rid of flutter in that direction) and one wall slanted/unregular (again - flutter). All other surfaces hard - no carpets etc! This results in an even RT60 curve and a lot of hf energy in the room. You could still put wood strips over the absorber wall to bring back some diffusion and high frequencies even more - but we never did that in these rooms after testing them.
My office is 2.20 after ceiling treatment, my listening room also. I don't think that's a serious health issue, I'm SITTING all day in these rooms and feel fine
.When planning a room for audio 2.20 is of course a no go. But when it's the only option ... you have to make it work. 2.20 is a cave anyways... (I loved to live in 3.3-3.5m rooms, you find them in Vienna. But you need a lot of treatment also - don't forget this >1m up there!)
Just a few measurements of my non environment room. 16cm BCA absorption on the ceiling, 16cm on 3 walls and a lot of additional absorption as moveable absorber walls in the back. Ready ceiling after floating floor and ceiling treatment 2.2m.
That's NOT THE RIGHT GOAL for a home cinema room! That's what you CAN achieve with not too fancy acoustic work.
But you can't let rt60 of 0,4s in such a small room, these guidelines are for much bigger rooms.
For recording rooms I like to do a ring around the ceiling/wall corner with deeper absorbers and fit the rest of the ceiling to the situation/reflection points. But with a low ceiling you need absorption in areas where microphones are. At least one wall completely absorptive (to get rid of flutter in that direction) and one wall slanted/unregular (again - flutter). All other surfaces hard - no carpets etc! This results in an even RT60 curve and a lot of hf energy in the room. You could still put wood strips over the absorber wall to bring back some diffusion and high frequencies even more - but we never did that in these rooms after testing them.
Your room looks very good @IamJF, but it's not particularly thread-relevant (you do have the so called "minimum height" of ~8feet/2.5m). Your posts are also jumping fast between room types & sizes, not easy to follow. Maybe we can (re)focus a bit.
Same as the OP, I am only interested in a listening/media room for music/cinema/games. One with pretty serious size limitations: ~2.2m / 7.2feet height and a surface in the ballpark of ~25m2 / 270sq.feet. Around the EU, that would be a typical basement room (with hard & thick concrete walls).
I am not convinced that such a room can sound "great" ... but will happily change my mind if someone posts detailed measurements from a similar-size room.
Same as the OP, I am only interested in a listening/media room for music/cinema/games. One with pretty serious size limitations: ~2.2m / 7.2feet height and a surface in the ballpark of ~25m2 / 270sq.feet. Around the EU, that would be a typical basement room (with hard & thick concrete walls).
I am not convinced that such a room can sound "great" ... but will happily change my mind if someone posts detailed measurements from a similar-size room.
Last edited:
I have the same dilemma!
do you have the ~same room/dimmensions too?
P.S.
since these are pretty common dimensions for basement rooms, it may be a good idea to create a dedicated thread
Last edited:
How does an ls50 meta in the ceiling even work?
You mount at the dolby spec in terms of angle and distance, then "toe" it in to face down and towards you at that angle?
Assuming atmos overhead, not atmos front height wall.
I think there are better option for ceiling speakers though.
Arendal 1961 or 1723 bookshelf or Perlisten R4b or S4b already have VESA mounts and don’t need modification like the LS50.
Having speakers directly pointed at the listener should always be better than downfiring ceiling speakers like the Kef Ci series. But it obviously doesn’t look as clean as in ceiling speakers that are hidden inside the ceiling or inside a large ceiling absorber.
Arendal 1961 or 1723 bookshelf or Perlisten R4b or S4b already have VESA mounts and don’t need modification like the LS50.
Having speakers directly pointed at the listener should always be better than downfiring ceiling speakers like the Kef Ci series. But it obviously doesn’t look as clean as in ceiling speakers that are hidden inside the ceiling or inside a large ceiling absorber.
