Please can you help me decide if this room size is good?

  • Thread starter Russell Burrows
  • Start date
R

Russell Burrows

Audiophyte
Hi, first post here so thanks for reading this.
I'm undecided between two options for a home theater room size.
I'm worried about room modes as the entire budget will be towards building a concrete shell made of steel re.b.a.r.s, concrete and filled cinder block.
So once built I'm unable to move a wall.

OK I'm undecided between a 10 meters room length and an 11 meters room length with the other dimensions being 7 meters width and ceiling height of six meters.

This is a diy low budget project so I'm really wondering on the impact of room modes in the 10m versus 11m lengths.
Thanks.
My concrete subwoofers box is built but the concrete home theater shell is pending.
 
lovinthehd

lovinthehd

Audioholic Jedi
I can not help but that is one immense theater room! Staying tuned to see what you might get....assume you've used the various room mode calculators?
 
Bobby Bass

Bobby Bass

Senior Audioholic
Wow that is a huge room. Unless anyone knows of a formula for the perfect dimensions for sound I would go bigger. You rarely hear someone say they wish they had less space for their theater room. The more space the more options you’ll have as you use it over time. Keep us posted and good luck with your project!
 
Verdinut

Verdinut

Audioholic Spartan
Hi, first post here so thanks for reading this.
I'm undecided between two options for a home theater room size.
I'm worried about room modes as the entire budget will be towards building a concrete shell made of steel re.b.a.r.s, concrete and filled cinder block.
So once built I'm unable to move a wall.

OK I'm undecided between a 10 meters room length and an 11 meters room length with the other dimensions being 7 meters width and ceiling height of six meters.

This is a diy low budget project so I'm really wondering on the impact of room modes in the 10m versus 11m lengths.
Thanks.
My concrete subwoofers box is built but the concrete home theater shell is pending.
The 11 meter length is a little bit close to 12 meters which is double the size of the height. I would definitely recommend the 10 meter length, to reduce acoustic room mode effects.
 
R

Russell Burrows

Audiophyte
The 11 meter length is a little bit close to 12 meters which is double the size of the height. I would definitely recommend the 10 meter length, to reduce acoustic room mode effects.
Hey thanks I had not considered that but now I have another concern as to reduce roof leaks in the concrete I was told to go for a vaulted ceiling from 5 meters edge to a peak of 8 meters at room center.
Hmm 5 plus 1.5 gives me 6.5 meters ceiling height so yup I'm going with ten meters length.
I will update with pictures as I build or I will begin a new home theater build thread with pictures as I buy materials and slowly build.

Thanks again for the information.
 
TLS Guy

TLS Guy

Seriously, I have no life.
Hi, first post here so thanks for reading this.
I'm undecided between two options for a home theater room size.
I'm worried about room modes as the entire budget will be towards building a concrete shell made of steel re.b.a.r.s, concrete and filled cinder block.
So once built I'm unable to move a wall.

OK I'm undecided between a 10 meters room length and an 11 meters room length with the other dimensions being 7 meters width and ceiling height of six meters.

This is a diy low budget project so I'm really wondering on the impact of room modes in the 10m versus 11m lengths.
Thanks.
My concrete subwoofers box is built but the concrete home theater shell is pending.
The number that is way off is the height of 6 meters. That totally ruins the optimal ratios and is way off. By my calculations that height is way, way out of order, and will make the room ring like a barrel. The difference between 10 and 11 meters is insignificant. Your length to width ratios are in excellent territory.

When I designed my room I worked out essentially optimal dimensions. The room sounds fantastic, and it height is 2.75 meters going to 10 meters is fine, but six meters high makes the room dimension ratios awful.

Incidentally, my room has two concrete walls, the left, and back. The front is stud, but really strong, braced and filled with damping. The right wall is the equipment wall largely. Now concrete is rigid, which is good, however it is all down hill after that. So you cover the concrete with a think layer of insulation ir other dampening material and cover that with sheet rock.

Front.



The back wall. This contains shelving as well as the rear back speakers, to stop slap echo.



The equipment wall.



Make sure in a room that long you tier it, and place damping heavily under the floor.



Make sure you place adequate conduit. All AV wiring MUST be in conduit. Also note the fan duct to extract air from above the power amp case.







Make sure you have adequate AC powering all over the place. Make sure you have power in the vicinity of all speakers, as I'm sure the future is to active powered speakers. Conduit is important to all speakers, not just for speaker wire. But going forward all speakers are likely to require an ethernet connection.



Make the HT room the hub of the house Ethernet.





You are correct that AV rooms require very careful planning. You not only have to plan for now, but future proofing is also vital. This last point is crucial and seldom thought of.

Also, do what I did and create an equipment chase so you can walk behind it. This is a big point.

You are also right, that if you build in concrete there are no do overs, so you HAVE to get it right the first time.
 
Last edited:
TLS Guy

TLS Guy

Seriously, I have no life.
Hey thanks I had not considered that but now I have another concern as to reduce roof leaks in the concrete I was told to go for a vaulted ceiling from 5 meters edge to a peak of 8 meters at room center.
Hmm 5 plus 1.5 gives me 6.5 meters ceiling height so yup I'm going with ten meters length.
I will update with pictures as I build or I will begin a new home theater build thread with pictures as I buy materials and slowly build.

Thanks again for the information.
See what I just told you. DO NOT VAULT the ceiling. By all means have adequate slope in the roof, but put a ceiling below.

I have a feeling if you do not listen to me, you will make some absolute acoustic howlers.
 
R

Russell Burrows

Audiophyte
See what I just told you. DO NOT VAULT the ceiling. By all means have adequate slope in the roof, but put a ceiling below.

I have a feeling if you do not listen to me, you will make some absolute acoustic howlers.
Thanks for the information.
However I placed a 2.75 meter in amroc mode calculator that I found yesterday and it's showing that it's too small.
I had a look at Anthony Grimani and Dennis Foly and from that information the smallest dimension is the most problematic.
This being the ceiling in that I'm not going to vault it but it is going to be 6 meters ht or more at peak slope or plain with a diy round diffusion of 5 meters radius and some absorption .
15 percent absorption and 20 percent diffusion are the goals but I'm going to start with a bare room then modify.
Thanks for the rest of the information as that was really good.

Most home theater n planning benefit from going from 8 foot ceilings to 12ft to 15ft or more as this better approximates the room where the event was recorded.
 
Verdinut

Verdinut

Audioholic Spartan
Thanks for the information.
However I placed a 2.75 meter in amroc mode calculator that I found yesterday and it's showing that it's too small.
I had a look at Anthony Grimani and Dennis Foly and from that information the smallest dimension is the most problematic.
This being the ceiling in that I'm not going to vault it but it is going to be 6 meters ht or more at peak slope or plain with a diy round diffusion of 5 meters radius and some absorption .
15 percent absorption and 20 percent diffusion are the goals but I'm going to start with a bare room then modify.
Thanks for the rest of the information as that was really good.

Most home theater n planning benefit from going from 8 foot ceilings to 12ft to 15ft or more as this better approximates the room where the event was recorded.
Are you going to listen only to recordings done in the room you are referring to? If not, then why would you try to copy dimensions of one particular recording room?
 
R

Russell Burrows

Audiophyte
Are you going to listen only to recordings done in the room you are referring to? If not, then why would you try to copy dimensions of one particular recording room?
Because most rooms that recorded movies, music and TV shows have ceilings that are more than 8ft?
The sonic signature of the listening room is very important and while it may be possible to overcome the problems of a very small room it will be very expensive to treat.

A simpler solution is a bigger room with more space to fit long wavelengths especially in new room build without the limitations of a low 8ft ceiling.

And because my broke and nearly empty wallet budget of 50 to 150 dollars weekly can slowly buy build materials until a ten thousand dollar room is built that's a good size range versus building a tiny room and needing 100,000 dollars in treatment to fix that way out of my league of a few dollars weekly budget.
 
TLS Guy

TLS Guy

Seriously, I have no life.
Because most rooms that recorded movies, music and TV shows have ceilings that are more than 8ft?
The sonic signature of the listening room is very important and while it may be possible to overcome the problems of a very small room it will be very expensive to treat.

A simpler solution is a bigger room with more space to fit long wavelengths especially in new room build without the limitations of a low 8ft ceiling.

And because my broke and nearly empty wallet budget of 50 to 150 dollars weekly can slowly buy build materials until a ten thousand dollar room is built that's a good size range versus building a tiny room and needing 100,000 dollars in treatment to fix that way out of my league of a few dollars weekly budget.
Your thinking is totally erroneous, and actually absurd.

There is no formula that I can find that supports your room ratios. If you want ceilings that high then the room needs to be much longer and wider as well. It is wrong to think that the wavelength of the original sound has to fit in the room. That nonsense was debunked years ago.
 
R

Russell Burrows

Audiophyte
Your thinking is totally erroneous, and actually absurd.

There is no formula that I can find that supports your room ratios. If you want ceilings that high then the room needs to be much longer and wider as well. It is wrong to think that the wavelength of the original sound has to fit in the room. That nonsense was debunked years ago.
Mode calculator says ceiling of 8ft or 2.75 m is just bad as I can see modes all the way up to 180 hertz yet plug in 6m and it's all golden past 80 hertz.

You are not makeing sense as a tiny room ceiling of 8ft where most bass wavelengths do not fit despite a golden ratio is not going to play nice with the subwoofers at 15 hertz.

You do have a point where 7m width is a bit close to 6m ht but it's not the same as having two identical measurements as a typical square room .

And the subwoofers are definitely not going in the corners where the corner loading of a room will exacerbate a problem.
Just curious why the insist on 8ft ceiling when most good home theater installation are at least 12ft with quite a few expensive ones doing 15ft or more ceiling height.
Thanks.
 
TLS Guy

TLS Guy

Seriously, I have no life.
Mode calculator says ceiling of 8ft or 2.75 m is just bad as I can see modes all the way up to 180 hertz yet plug in 6m and it's all golden past 80 hertz.

You are not makeing sense as a tiny room ceiling of 8ft where most bass wavelengths do not fit despite a golden ratio is not going to play nice with the subwoofers at 15 hertz.

You do have a point where 7m width is a bit close to 6m ht but it's not the same as having two identical measurements as a typical square room .

And the subwoofers are definitely not going in the corners where the corner loading of a room will exacerbate a problem.
Just curious why the insist on 8ft ceiling when most good home theater installation are at least 12ft with quite a few expensive ones doing 15ft or more ceiling height.
Thanks.
Actually I said a range of 8' to 10' was optimal, actually my calculator says 9' is the optimal number, and that is what I used for my room, and it works very well.

The problem you will have with higher ceilings is the timing of the reverb. It has been shown for years, that a room with ratios that have the same proportions as a shoe box are optimal. I gave you the optimal dimension ratios. Stop going down the road of thinking wavelengths don't fit. That is wrong and erroneous thinking.
 
R

Russell Burrows

Audiophyte
Actually I said a range of 8' to 10' was optimal, actually my calculator says 9' is the optimal number, and that is what I used for my room, and it works very well.

The problem you will have with higher ceilings is the timing of the reverb. It has been shown for years, that a room with ratios that have the same proportions as a shoe box are optimal. I gave you the optimal dimension ratios. Stop going down the road of thinking wavelengths don't fit. That is wrong and erroneous thinking.
Thanks.
Interesting.
I went back to a church to measure since it sounded good yesterday so I changed my room measurements to 1000 l, 750 width and 550 ht and it now fits good in something called the bolt area in the amroc mode calculator.

The reverb time hmm it says .4 but I remember Anthony Grimani saying. 3 is good?
I will just have to see if I can change that since other stuff looks good in the bonello distribution and after a small donation at the church I played a 1 minute sample of a few edm songs and a quick Jhon wick scene on a small subwoofer and sat speakers and for a bare concrete church it sounded amazingly good.

Oh well there's compromising in everything.
I really do appreciate your help.
Thanks.
 

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