Learning about my room and my sound..


Ok, so I have a Radio Shak SPL and I see all these posts on here about people's speakers and performance, now maybe I am an idiot or overwhelmed but how and where do you start to test the performance and synergy of your speakers in your room? I know there are tons of threads but can it be explained to me please?
All I know is I have a SPL that I use to calibrate, and I have a test disc but it is of high tones, so I assume I need a low frequency test disc and then what please>?

P.S. please be kind I know alot of you may laugh at my question but I really want to know what to do
thanks Chad
chadnliz
Your not an idiot, but if not already, you may be overwhemed by the task you propose to undertake. Some of us have been lucky enuf to have heard good stuff in an ideal room, properly tuned and set up. That gives us a great basis to evaluate our systems capabilities and possible limitations in our own rooms.

I looked at your system photos. Do you sense you have a problem that you need to solve or are you interested in tweaking your system?

From a two channel point of view your system doesn't 'appear' to be optimally set up. Obviously I've no info on your room size nor the amount of flexibility that you have, nor am I clear if your trying to dial in just the two channel audio or if your are trying to dial in multi channel HT. The following observations are just based on typical results I would expect - I have not actually heard your speakers in your room. I'm just guessing that these could be some problem you may have encountered.

I would suspect that you might have a bloated bass from the proximity of your speakers to the rear wall. I would also suspect that the back wave from the speakers should strike a more dispursive surface - yours looks too flat and too close. Probably makes your highs sound elevated and 'flat', no real sense of depth in the image. Your speakers appear off center in the room and could cause an imbalance due to different side wall reflection arrival times, and the toe in of your speakers appear different. The location of your listening chair is not evident so I can't comment on its placement.

Now to the SPL meter and a test disc. Stereophile has a series of test discs with low frequency (only)1/3d octave tones from 200hz to 20hz, and full spectrum. I like these as the tone is pink noise and steady. Other disc's I heard have not been pink noise and the tone is not steady making it difficult to calibrate. The lowest bass capabilities of the SPL meter are rolled off and you need to apply correction. (The table has been printed many times on this site).

Then using a standard program model for initial speaker and listener position selection (see the Cara program on Rives' site) you start measuring the frequency response. You will need some graph paper so you can record the results at each frequency. Your goal in the bass is to move the speakers and listening position about until you get as flat a frequency response in the bass as possible. Once you have done that you focus on the mids and highs, moving the speakers and listening position about minimally until you produce a sound that is very smooth. Correct toe is a critical issue for smoothness and resolution. If you have done your job perfectly you should not feel like the sound behind the plane of your speakers has any barrier to the sense of depth (i.e. no rear wall). Unless you have an apparent spike in the upper frequencies you feel you want/need to identify with the SPL meter I would suggest you just use your ear for the mid's and high's.

Hope that helps you get started.
Thanks guys, my speakers are pulled out now, they were not in the picture, the panels are 36 inches from back wall, the system is center in room, even if it does not appear so...my room is 13.6 X 19 on the right side wall it opens up to the dining room at about 14 feet back form system wall, on the left wall there is a medium size window centered in room, and on back wall a standard window in center behind couch. There is a small sofa under the window on the side wall aswell. I am just unsure of what to do with the numbers in hand once I have them, if it I get spikes in the highs that would mean I need to absorb some reflections correct? and if I get highs in the low frequency I need to trap some corners perhaps or no?
Ok well thanks a bunch again, and to answer newbie, I am simply trying to check and tweak if needed I dont hear anything alarming, just not sure if I am used to hearing flawed sound if that makes sense. I know my gear isnt the best or anything but I simply want to get the best out of it....cheers
Rives audio sells a test disc which has tracks that are corrected for the Radio Shack meter error. If you use the RS meter, this is the disc to use.
Chadnliz, in response to 'what do I do' with a reading. I assume that you mean that once you have moved your speakers and listening position about and have smoothed out the frequency response as much as possible by doing so, then you should consider how to smooth it out further. Bass is tough to deal with and treatments are frequency dependent so you need to chart the exact frequency you have problems with and then ask for specific advise. Highs typically can be smoothed out by treating reflection points. You can use furnishings or you can get professional treatments, I prefer the former. Keeps it looking like a real room. But, be warned. This is a slow and evolving process. It can take weeks or months of moving and listening before you dial in the optimum set up.

Eldartford, I don't know if you have actually listed to the Rives disc but when I used it in my system I found many of the individual test tones were not steady and because of that were difficult to track. Not so with the Stereophile disc. Is that problem unique to me? What did you experience?
Newbee...Yes I used the Rives disc, but only briefly because I got myself a spectrum analyer that is much easier to use. I don't recall the problem you mention, but I will put the disc on again and look for it. I will also look (with the analyser) at the electrical signal to see if it is stable. What I did notice is that with the higher frequencies quite small movement of the mic causes large SPL variation. You can also hear this when you move your head around.