[WGH]

Way back in 1993, Audio Magazine had an interesting article about finding room modes, this is a good primer before moving on to the more in-debth articles on the RealTraps site.

Included in the article is a list of CD's (1988) that have audible components below 32 Hz, room dimension ratios based on third-octaves, and a room mode computer program written in BASIC (all PC's still used DOS in '93).

Below is a pdf file of the article:
Taking Up Resonance: Finding Room Modes On Your Computer
http://www.wghwoodworking.com/audio/AudioMagazine-FindingRoomModes.pdf

I took the original computer code and re-wrote it using FreeBasic so it would run on Windows. Unzip the file and double click on roomode.exe to run, nothing to install and nothing is written on your computer. The directions for decifering the ones and zeros in the output is in the article (remember folks, this was written 2 years before Windows 95 was released).
http://www.wghwoodworking.com/audio/roomode.zip

The easiest way to save or print the output is to use PrintKey, here is the free version that works perfectly with XP.

Enjoy

Wayne

[TerryO]

Wayne,
That's excellent information. The late, lamented Audio magazine was the only consistent, reliable source of technical information available to the general public. I let my subscription lapse in the late 80's and I've always been sorry.

Thank you for making this available.

Best Regards,
TerryO

[Ethan Winer]

Great stuff Wayne. People did understand room acoustics back then, but nobody cared. Now almost nobody cares.

I took the original computer code and re-wrote it using FreeBasic so it would run on Windows.

I have a ton of old DOS code too - long live BASIC! - but for anyone interested in predicting modes using a more modern interface here's mine:

Graphical Mode Calculator

If anybody cares to see the Liberty Basic source code, email me from my company's site and I'll be glad to send it to you.

--Ethan

[JakeJ]

If any one might be interested I found a chart of musical notes and their frequencies with the wavelengths in cm, in, and ft. I created an Excel spreadsheet for easy viewing. You can see which musical notes excite your room's nodes. Must be why bass measurements are so important.

Here it is.

Jake

[Ethan Winer]

This too: