What is a rectangular room?

producer12999

Member
Hello, I would like to move out and look for an apartment here in Germany that has a large rectangle room, as symmetrical as possible.
Is 5m x 5.50m also rectangular? This is just an example. What is the definition of rectangular for you in the studio area? (5x6 or 5x7?)

I am looking for an apartment with a room of at least 18-20 square metres. Unfortunately, all the apartments only have distorted wide-angle shots on which you can never tell whether the room is rectangular or square. That gets stressful, unfortunately floor plans are very rare on popular platforms here.

For example, I found two rooms, one with 5x4, one with 6x3,3. What would be better? -> But they have several doors on the side walls, so far not the best choice. I will have to move a lot of mobile absorbers back and forth when I need to go to the toilet or kitchen.

Thank you!

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Keith_W

Major Contributor
The closer the dimensions are to each other, the closer the standing waves will be. Having said that, Toole says in his book that there is no such thing as an ideal room, and he has cited many studies of others trying to mathematically calculate the ideal listening room.

As for whether you go for the wider room or the narrower room, I note that the width dimension of the narrow room (6 x 3.3) is about half of the length, which will give you the same standing waves. I think the wider room (5 x 4) is better.

kacos

Active Member
What is the definition of rectangular
Fyi, rectangular is any surface with 90° angles:

Rectangular room is one where all it's sides are at 90° angle to each other

Ron Texas

Master Contributor
Forum Donor
Ever notice how the predicted in room response chart the Klippel makes has no suck-outs? I wonder what kind of room they were simulating. I think larger rooms with high ceilings work better.

voodooless

Grand Contributor
Forum Donor
Rectangular room is one where it's sides are at 90° angle to each other
Good point. I think the OP meant square rooms

The again, having a square room about halves the amount of standing waves

NTK

Major Contributor
Forum Donor
FWIW, here is an article from the Journal of the the Acoustical Society of America (JASA) Express Letter for your reading pleasure.

Abstract:
Rooms for music rehearsal, sound studios, control rooms, etc., need a smooth frequency response. For that reason,
the frequencies of the room modes should be spread as well as possible, and this is controlled by the aspect ratios of the
dimensions. The relative variance of the frequency spreading of the lowest 25 room modes is applied as a quality criterion.
The results have revealed that the length-width ratio is much more important than the width-height ratio. The length-width
ratio should be within 1.15–1.45. The height can be chosen more freely without compromising the acoustical quality.

OP
P

producer12999

Member
Hello, thank you for the message.

Okay, the ratio should be 1.15-1.45.
So when the room is for example 4 m wide (4x1), then it must be at least 4x1.15 long. (so the room should be at least 4,6 m in lenght)

Am I correct?

Thanks to you, this short is also very interesting

NTK

Major Contributor
Forum Donor
Hello, thank you for the message.

Okay, the ratio should be 1.15-1.45.
So when the room is for example 4 m wide (4x1), then it must be at least 4x1.15 long. (so the room should be at least 4,6 m in lenght)

Am I correct?
Yes. From Table 1 in the article, the ratio is defined as length/width.

DVDdoug

Major Contributor
So when the room is for example 4 m wide (4x1), then it must be at least 4x1.15 long. (so the room should be at least 4,6 m in lenght)
Not "at least"... Exact or "close-to".

Of course, you won't find such an ideal room unless it was specifically built as a music room.

Balle Clorin

Major Contributor
Jezsz, are flats in Germany adverttised/announced/sold without a floor plan? , unbelievable. It cannot be correct.

A square symmetrical room (cubic) is the last thing you want for audio..

OP
P

producer12999

Member
Jezsz, are flats in Germany adverttised/announced/sold without a floor plan? , unbelievable. It cannot be correct.

A square symmetrical room (cubic) is the last thing you want for audio..
It's true mate. With the majority of the apartments that could be suitable for me is not a floor plan in the listing. Floor plans are then available on request, but takes time.

Balle Clorin

Major Contributor
Strange country/system. Where I live it is included, and if not , no more than a mouseclick away. Any realtor would deliver it within minutes if requested

OP
P

producer12999

Member
The closer the dimensions are to each other, the closer the standing waves will be. Having said that, Toole says in his book that there is no such thing as an ideal room, and he has cited many studies of others trying to mathematically calculate the ideal listening room.

As for whether you go for the wider room or the narrower room, I note that the width dimension of the narrow room (6 x 3.3) is about half of the length, which will give you the same standing waves. I think the wider room (5 x 4) is better.
damn, makes sense. Thanks!

OP
P

producer12999

Member
Strange country/system. Where I live it is included, and if not , no more than a mouseclick away
Of course, Germany is completely lost, the infrastructures and laws come directly from the Stone Age. Hopefully one day I can emigrate to Switzerland.

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bert stoltenborg

Member
Hello, I would like to move out and look for an apartment here in Germany that has a large rectangle room, as symmetrical as possible.
Is 5m x 5.50m also rectangular? This is just an example. What is the definition of rectangular for you in the studio area? (5x6 or 5x7?)

I am looking for an apartment with a room of at least 18-20 square metres. Unfortunately, all the apartments only have distorted wide-angle shots on which you can never tell whether the room is rectangular or square. That gets stressful, unfortunately floor plans are very rare on popular platforms here.

For example, I found two rooms, one with 5x4, one with 6x3,3. What would be better? -> But they have several doors on the side walls, so far not the best choice. I will have to move a lot of mobile absorbers back and forth when I need to go to the toilet or kitchen.

Thank you!
Room dimensions should differ at least 5 % and integer multiples should be avoided.
Realize that standing waves (modes) are not a problem: isolated standing waves are! When the dimensions of a room are similar the standing waves add and become even more uncontrollable. So the remark that a cuboid reduces problems because you have only 1/3 of the standing waves compared to another room is (I hope) a joke.
All this research on golden ratio's is outdated, when you do a search on scientific papers on this topic you can see that; Floyd Toole who sustaines these findings is already mentioned here. The methods are flawed.
Also take into account that calculations on modes are not as straight forward as you might think. You need a room with VERY rigid boundaries to have the modes exactly where they are calculated.
I could show an example of a room that is build of studwalls constructed with 18 mm OSB-board and 2 layers of 12.5 mm gypsum board and the modes show exactly the patern that REW room simulator does, but all the modes are shifted a little bit. This is because the absorption the wall generates is influencing the theoretical model.
Adding furmiture and other bulky stuff is also shifting modes.

bert stoltenborg

Member
Of course, Germany is completely lost, the infrastructures and laws come directly from the Stone Age. Hopefully one day I can emigrate to Switzerland.
If you think Germany sucks, don't come to the Netherlands .

OP
P

producer12999

Member
Room dimensions should differ at least 5 % and integer multiples should be avoided.
Realize that standing waves (modes) are not a problem: isolated standing waves are! When the dimensions of a room are similar the standing waves add and become even more uncontrollable. So the remark that a cuboid reduces problems because you have only 1/3 of the standing waves compared to another room is (I hope) a joke.
All this research on golden ratio's is outdated, when you do a search on scientific papers on this topic you can see that; Floyd Toole who sustaines these findings is already mentioned here. The methods are flawed.
Also take into account that calculations on modes are not as straight forward as you might think. You need a room with VERY rigid boundaries to have the modes exactly where they are calculated.
I could show an example of a room that is build of studwalls constructed with 18 mm OSB-board and 2 layers of 12.5 mm gypsum board and the modes show exactly the patern that REW room simulator does, but all the modes are shifted a little bit. This is because the absorption the wall generates is influencing the theoretical model.
Adding furmiture and other bulky stuff is also shifting modes.
Hey, thanks for your detailed answer. Yes, I won’t choose any room dimensions like 3m x 6m! Do "integer multiples" actually include dimensions such as 4m x 6m?

If I found the perfect room, I might even ask here again, but the @NTK post helped me a lot.

What’s wrong with the Netherlands?

bert stoltenborg

Member
Hey, thanks for your detailed answer. Yes, I won’t choose any room dimensions like 3m x 6m! Do "integer multiples" actually include dimensions such as 4m x 6m?

If I found the perfect room, I might even ask here again, but the @NTK post helped me a lot.

What’s wrong with the Netherlands?
4 m means a mode at speed of sound divided by 2 x 4m. Speed of sound is at room temperature somewhere in the 340 m/second region.
So 340 / 8 = 42.5 Hz
340 / 12 = 28.3 Hz.
No problem.
A mode has complementary modes at integers of the basic frequency. So a 42.5 Hz mode has harmonics at 85, 127.5, 170 etc Hz.
That is the integer you should avoid; the integer multiplying the Hz of the mode. With room dimensions it means that 2 x 8 meters is 16 m, 340 / 16 = 21.5 Hz.
If you divide 8 meters by 2 you get 4; 340/4= 85, another harmonic of the fundamental mode.

When I tell you what is wrong in the Netherlands I probably get kicked off this forum .

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OP
P

producer12999

Member
4 m means a mode at speed of sound divided by 2 x 4m. Speed of sound is at room temperature somewhere in the 340 m/second region.
So 340 / 8 = 42.5 Hz
340 / 12 = 28.3 Hz.
No problem.
A mode has complementary modes at integers of the basic frequency. So a 42.5 Hz mode has harmonics at 85, 127.5, 170 etc Hz.
That is the integer you should avoid; the integer multiplying the Hz of the mode. With room dimensions it means that 2 x 8 meters is 16 m, 340 / 16 = 21.5 Hz.
If you divide 8 meters by 2 you get 4; 340/4= 85, another harmonic of the fundamental mode.

When I tell you what is wrong in the Netherlands I probably get kicked off this forum .
I think I got it.

If you have dimensions like 3x6 m it can be that the fundamental frequency (340/6) and the octave above (340/12) are eliminated simultaneously and then MONSTER dips are created. 2 "smaller" different dips can be treated better in the bass range.

bert stoltenborg

Member
I think I got it.

If you have dimensions like 3x6 m it can be that the fundamental frequency (340/6) and the octave above (340/12) are eliminated simultaneously and then MONSTER dips are created. 2 "smaller" different dips can be treated better in the bass range.
Standing waves are resonating patterns in a room. So you have spots where you have way to much of that frequency because the wave and it's reflections add and increase the total pressure. and on other places you have none of it because the waves cancel each other. When you have to much (peak) there is maximum pressure. You can lower this by EQ.
When waves cancel eachother there is nothing, no pressure(null). You cannot eq that because there is nothing to decrease or increase.

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