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Tuning speaker / room response?

I finally did an experiment this afternoon to check out my speaker and room response. The graph below shows the results:

I got this using the Stereophile Test CD 2 tracks 15 through 18 using my system. The first one provides pink noise, the others give warble tones at the various center frequencies shown in the chart.

A Radio Shack SPL meter, in fast mode, C weighted, was used to to capture SPL levels. The meter was in the 80dB range. As C weighting rolls of above 10kHz, I did not show the rest of the spectrum.

Now this does not look all that flat to me, but I have never done this before. Can anyone give me an opinion on how good or bad this looks?

Also, it looks to me like a little room tuning might help. Anyone have any suggestions as to where to start with this?

Niels.
njonker
mikec
199 posts
 
Try going to www.headphone.com and click "reading stuff" and scroll down to "revenge of the giant toilet paper tubes" and read all information. Than go to www.cardasaudio.com and click "insights" and scroll to speaker setup and read all info. This should give you some info to flatten those BUMPS.
garfish
1,840 posts
 
Hi Njonker; first, it amazes me that you could import and show this graph here on Agon. 2nd, the graph itself is very interesting, and may well give me enough incentive to try doing what you did, as I have both the STPH CD 2 and a Rat Shack SPL meter. Rather than doing the 1st logical step as you have, ie the measurements, I bought five ASC tube traps, 11" dia. X 4 ft., and 3 panel traps, 15" X 4 Ft., and just tuned my 14 X 22 room by ear using these ASC products. There is also other furniture in the carpeted room, such as drapes, bookcases, CD storage etc. You obviously have sonic peaks in the mid-bass, mid-range, and low treble. Using the ASC products and ordinary furniture, it's my guess that you could significantly reduce those peaks. Thankyou for the excellent information. Craig.
cornfedboy
1,645 posts
 
like garfish, i'm really impressed with the fact that your post is like none i've ever seen. will you kindly share with us how you imported the graph?
njonker OP
107 posts
 
The graph is actually pretty simple to do. You put it on a web server, then include a link in your post. The link is done by a simple html tag.

Using square brackets in stead of smaller than / greater than signs, the tag looks like this: [img src="http://www.myhome.org/pics/roomresp.gif"]. You would of course use greater than in stead of [ and less than in stead of ].

Niels.
sean
6,231 posts
 
You need to take into account that the RS meter is not REAL accurate in the first place. There is a list of corrections that need to be factored in before you start "gutting" your room, buying room treatments, moving your speakers, etc... I can't seem to find the website that posted this info nor the sheet that i printed out with the specific corrections. Once i can locate either one of them, i will post it here unless someone beats me to it. Sean
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