Room Mode Calculator and Converter

[Sonnie]

hardman has been kind enough to furnish us with a couple of nice downloadable progams that might come in handy all along. Thank you hardman!

The first program is a Room Dimensions Mode Calculator. This is a Microsoft Excel Worksheet that allows the user to enter their room dimensions and then see how close/far apart the modes are for their space (program works for 0 to 300 Hz). To use the worksheet you will have to enable macros. Just enter your room dimensions (red) and then click the clear button and last the plot button.

.xls file: Room Dimensions Mode Calculator (Excel 2003 only)

.xls file: Room Dimensions Mode Calculator (for older Excel versions)

Remember: you must enable macros when it loads the program.


The second program is a very complete converter tool. This is not your ordinary converter... it has 22 different conversion categories and converts about anything that could possibly be converted.

.zip file with .exe program: Converter

[Ethan Winer]

Sonnie wrote:

hardman has been kind enough to furnish us with a couple of nice downloadable progams that might come in handy all along. Thank you hardman!

Agreed.

And for anyone who doesn't have Excel but uses Windows, here's a Mode Calculator program I wrote that has a few unique features:

www.realtraps.com/modecalc.htm

--Ethan

[ludwignew]

How should I use this if my room has asymetric dimensions?

[willy-be]

ludwignew wrote:

How should I use this if my room has asymetric dimensions?

The only program I know of that will acoustically model asymmetric rooms is CARA 2.2

Know in advance it's an extremely user hostile program with no support from the maker.
http://www.cara.de/ENU/index.php?loa...powerpack.html

[savior sound]

I am converting an already finished out basement that measures 26' x 12.5' x 7.8' ceiling. The 12.5' width and the ceiling cannot be changed but I did plan on creating a 4' deep closet to house the AVR & equipment and store movies/games etc. So the 26' length will change to something like 22' (or whatever would work best). I plugged in the room deminsions (see attached .xls) Now what do I do? Sorry for my ignorance!

Thanks

Steve

EDIT: sorry I couldn't attach file - too big.

[thewire]

savior sound wrote:

I am converting an already finished out basement that measures 26' x 12.5' x 7.8' ceiling. The 12.5' width and the ceiling cannot be changed but I did plan on creating a 4' deep closet to house the AVR & equipment and store movies/games etc. So the 26' length will change to something like 22' (or whatever would work best). I plugged in the room deminsions (see attached .xls) Now what do I do? Sorry for my ignorance!

Thanks

Steve

EDIT: sorry I couldn't attach file - too big.

Start to calculate sabins needed to tame room resonances.

[savior sound]

And how do I do that?

[thewire]

Here is a link to Sabine's Reverberation Formula with a calculator. If you are going to design a listening room, which I think you may be, this will help determine how live or dead the room sounds. There are different ways to go about it, and not all rooms are alike. Simply tell it what you intend to have on your walls, floor, and ceiling, and it gives you an aprox idea. Listening to the room will also help, and measuring the actual changes would be best, but this does give an idea what you will have to deal with. There are other calculators which allow you to also manually enter the absorption coefficients, but this may be easier.

http://www.sengpielaudio.com/calculator-RT60.htm

[savior sound]

OK, I'm starting to understand - thanks to the help section of your app Ethan. So to give you a little background, I am constructing a HT (music listening) room in my existing basement. As I stated earlier the constants are the 12'6" width and the 7' 9 1/4" high ceiling. The variable is the length which is 26' now but I plan to construct a wall approximately 4' from the existing back wall for a closet. Before I construct this wall, I am trying to figure out where would be most beneficial place (acoustically) to put it. Can someone make a suggestion as to what I should do? Bascially 12'6"x7'9.25"x? what (26' or less) would be the best room demension for movie/music listening. I understand that I will still have some treatments (bass traps, absorption, diffussion, etc.) to help but I want the best possible starting point. Does that make sense? Can anyone help me?

Thanks in advance,

Steve

EDIT: I also plugged in my projected room demensions (22' as the length) in the Sabine's Reverberation Formula calculator and got 0.45 @ 125 Hz, 0.71 @ 250 Hz, 0.81 @500 Hz, 0.68 @ 1 KHz, 0.45 @ 2 KHz and 0.41 @ 4 KHz. What does this mean?

[thewire]

savior sound wrote:

OK, I'm starting to understand - thanks to the help section of your app Ethan. So to give you a little background, I am constructing a HT (music listening) room in my existing basement. As I stated earlier the constants are the 12'6" width and the 7' 9 1/4" high ceiling. The variable is the length which is 26' now but I plan to construct a wall approximately 4' from the existing back wall for a closet. Before I construct this wall, I am trying to figure out where would be most beneficial place (acoustically) to put it. Can someone make a suggestion as to what I should do? Bascially 12'6"x7'9.25"x? what (26' or less) would be the best room demension for movie/music listening. I understand that I will still have some treatments (bass traps, absorption, diffussion, etc.) to help but I want the best possible starting point. Does that make sense? Can anyone help me?

Thanks in advance,

Steve

EDIT: I also plugged in my projected room demensions (22' as the length) in the Sabine's Reverberation Formula calculator and got 0.45 @ 125 Hz, 0.71 @ 250 Hz, 0.81 @500 Hz, 0.68 @ 1 KHz, 0.45 @ 2 KHz and 0.41 @ 4 KHz. What does this mean?

I think you will want to maximize the space while keeping things symetrical, room for seating and treatments. I stuck my wall where it was symetrical to sit between the support beams without obstructing the screen and speakers for example. I made my wall splayed (not straight) by a foot or so. I checked with the room mode caluclator and did minor changes to the inches. I started with a 14 foot wall and then moved to 13.5 foot one. I stuck it right before a null in my room that I could hear and so that the right corner sounded the same. I walked from the right corner over to the left and stopped when it sounded different. These nulls are in the same place now that I have walls.

[savior sound]

I still don't understand what the RT60 results mean.

[bpape]

RT60 should be taken with a grain of salt and used as a comparative reference. RT60 is really more for larger spaces. Basically what it's telling you is that you have .45 seconds from the time that a 125hz tone stops until it decays by 60 db. .71 seconds at 250hz, etc.

[Nic_swe]

yho, just a wee question regarding the excel file , I'm assuming that the height/width/length is in the unit feet rather than meter correct? Does the calculation work as a ratio, therefore allowing both units or do I need to convert my measurements from meters to feet?

cheers!

[bpape]

It's is feet. It needs to be converted. The issue is that if you have meters, the portion of the formula relating to the speed of sound would also need to change to metric parameters.

Bryan

[sandbag]

My attempt to use this calculator with Excel for Mac produced garbaggio. Since my room is the size it is, and according to Floyd Toole, knowing the modes is not that valuable in a small room multiple speaker environment, is there any reason to calculate the modes? I plan on treating the room until it sounds right to me, anyway.

[bpape]

The one thing modal calculations are useful for up front (if the room is existing) is to know WHERE physically in the room they'll be so you can set up seating properly. It's also helpful to be able to play with speaker positioning and sub positioning to potentially introduce opposing characteristics to help smooth the response.

Bryan