yet another room size ?

[seti]

I just did the room size search which yielded the modecalc link I was looking for but the bloody thing runs in DOS which I am sure my OS X unix command line doesn't know jack about LOL.....

In short I just measured my audio room and it has 11ft ceilingings. The room is 13.5 ft wide and 15.5 ft long. Just curious how this would stack up on the mode calc. It is not open on any walls and can be closed up pretty good.

Any info much appreciated thanks

[Olorin]

Hope this helps. My FreeBSD machine runs it just fine, so I don't really see that OS X is much of an excuse.

[seti]

LOL good one didn't think of DOS emulation LOL.

Are you running Gnome on FreeBSD? Once I got my teeth into OS X I ditched my linux distros and bsd except of course when I need a good firewall or router I use BSD. I usually don't have to reboot them except for power outages etc.

I also should have added that I am a modecalc newbie in fact till i started read these forums the room size never even entered my head as a possible component of my system.

I don't completely understand the output. Is this good bad or ugly?

Thanks again!!!!!!!

[Olorin]

A fellow $FREE_OS guy -- cool! I got used to KDE a long time ago, and though I've considered switching, I haven't come up with a compelling reason to do so. KDE is functional and very shiny, and it works well enough for me.

I like OS X too, though. I use it a fair amount at work. We're a mixed environment with about a dozen PC servers and two honking big SGI IRIX machines. I'm responsible for seven of the Windows servers as well as some of the functions on the SGIs. The Mac's interoperability is quite good, IMHO. If I were going to actually spend money on a computer, I'd likely get a Mac.

As for modecalc and the reason we're actually here, , I'm going to have to defer to Artto and others more knowledgeable than I am to interpret the results there. I'm just not into that stuff deeply enough to give anything better than a mildly wild guess.

[seti]

I'm a network/sysadmin for a small org get to use what I want.

Yeah I remember compiling linux kernel 1.3 ug nightmare. I've used it off and on fora while BSD always requires abit more tweaking but can't be beat for stability. SGI\irix are cool but they give me a rash. I use kde when I need to work and gnome when I want eye candy it's getting better though and with Sun pitching in to help with development it should come up nicely. I can't stand pc's but if you wanna talk job security yee freek'n haw.

Oops is this #Klipsch or #Geekout.

Thanks for the reply will wait for a reply from a modecalc interpreter.

[DrWho]

The room mode calculator is a device that shows us the frequencies that will turn into standing waves in our rooms. A single standing wave will have points in the room where total cancellation occurs as well as points in the room that could be 10dB louder than the original sound from the speakers. When looking at the mode charts and graphs, we are most interested in the number of modes within a certain bandwidth and the average spacing of those modes. Modes grouped together over a narrow bandwidth tend to work together, making more dramatic standing waves (thus, a worse frequency response). High densities of modes over large bandwidths is a good thing because the overall effects on the frequency response pretty much get cancelled out everywhere else. I think at frequencies between 5kHz and 10kHz that there are usually thousands of standing waves with an average spacing of only a few HZ. It's only down in the lower registers that our spacing begins to spread out and then we're stuck trying to deal with them.

On the graph above, the four modes from 145Hz to 182Hz should result in a flatter frequency response than the three modes from 205 to 218.

The modes at 51, 73, 84, 103, and 109 Hz are probably the most damaging as they are all at key bass frequencies. It's possible that moving the listening position and speaker placement can help minimize these effects, but I'm thinking some proper room treatment is going to be the only solution. Also note that 103Hz (well 102Hz would be perfect) is a harmonic of 51Hz. These two frequencies are going to amplify each other and have peaks and nulls in similar locations.

Anyways, the basic conclusion is that this room has poor modal response (just like the rest of us). That's not to say it's awful though as it could be much worse. If the room dimensions were better, then you'd see less clustering (frequencies around each other) and a more natural decay towards less modes in the lower frequencies. Keep in mind that unless our room is fricken huge that we're going to experience less modes in the lower registers simply because of the size of the wavelengths.