Assessing room response

I see many folks talking about the radio shack SPL meter. I am a beginner and would like to try and see how my room is responding, what is the best way to start?
Go to real traps website and burn the test tones to CD that they offer. If you do a search or go on the Rives Audio website you can find a compensation chart to correct for the inaccuracy of the meter at low frequencies. Then just run the sweeps. You can also buy pre-made frequency sweep CDs.
Jusr remember, if you like the sound, it doesn't make any difference what other's think.
Are you asking how to use the equipment, or what equipment to get? Equipment wise, a Radio Shack analog or digital meter, a Stereophile test disc with 1/3 octave test ones using pink noise (which I prefer over pure frequency tones), a conversion list of low frequencies in the RS meter - the actual frequencies at 20hz are much higher than recorded but by 100 hz the RS meter is fairly correct) and if your going to play with speaker set up, some graphpaper so you can chart the FR from tests in a graphic way, and see from this how different speaker and listening positions change as you move things about. If you have any questions about its actual use, just ask.
I you have a PC try Room EQ Wizard with your Rat Shack meter.
I just did this over the last week. Go to the Rives website as mentioned above and get the test CD. Use tracks 32-63 with your Radio Shack sound meter

The CD has 20hz tones up to 20,000 I think. I have a nice sub and many room panals so I wanted to be sure all was right.

I plotted the room's response curve on Rives graph paper downloaded from their site. I used the test CD to better blend my sub, change the placement of some sound panals, move furniture and finally tweek my speaker placement.

After about 5 hours of work (fun) I greatly improved my room's response to very near a flat curve. Bass is flat from 20 -100 hz. I only have three small peaks of less than 3-5 db. throughout the spectrum.

Sound improvement was noticable and well worth the effort.
There is a free program called Audacity which can generate all kinds of test tones and noises (white, pink, brown). You can play back those test tones directly from Audacity or export them and burn them on CD. I use it with a RS meter to adjust the sub of my Vandy 5. They work very well.
One thing to note is that the Radio Shack meter has well documented errors at lower frequencies, and most of the test tones don't account for that. So, you can print a chart of numerical adjustments that take into account the errors and let you add/subtract from your readings to get the true value. If you use the Stereophile Test CD tones, or most of those you download, this will be true. The Rives CD already adjusts the tones, so you can skip the manual math step and not adjust you readings before plotting them.

This is way easier in practice than it all sounds. Here's a couple of other tips:
Get a handful of colored pencils or pens and mark tape on your floor to denote speaker & seating positions. Plot the graph in matching color. Tweak your position of speaker or seating and repeat.
Don't freak if you get some strange results. This is why we treat rooms, and many conclude that their room is the component that most affects the results.
If high frequencies are wacky, try panels at first and then second points of reflection. To smooth out bass peaks and troughs try bass traps in the corners behind speakers. Measure again, and you'll see what benefits you get...Cheers,
Don't freak if you get some strange results. This is why we treat rooms, and many conclude that their room is the component that most affects the results.

Absolutely. Expect to be disappointed compared to a stereophile speaker freq plot...
I just did this a few months ago. I did my test at 80db. I read that If you can do your test at 90 db you will get more accurate results. The only advice I have is, If you have earplugs, I would wear them. I started without them, but even at 80db, by the time I got from 30hz to 60hz in 1 hz intervals I had a headache. If you have a tripod the meter mounts nicely to the top. Good luck, it will add another dimension when you look at your.
I did it at 80db also. Yes, the before and after graph difference is a wonderful thing to behold.