Home Theater Forum and Systems banner
1 - 5 of 5 Posts

·
Registered
Joined
·
75 Posts
Discussion Starter · #1 ·
Hi guys!! Ive spent countless hours trying to achieve an overall flat response from my small room. I have the low end as good as Ive ever seen it in this room but do have a significant null @90hz I'll attach the file, as well as a the freq and waterfall graphs. Any help, questions, or comments are greatly appreciated!!!

The room is very small. 12' 2" width x 7' 6" length x 7' height. Ive tried the screen(basic 60" plasma) on the short wall but get a wide nasty null around 60hz. Setup is Onkyo 929, (2) crown xls 1500, polk audio monitor 70's, Polk cs2, polk tsi200, and dual XV 15's. Pics will give a better idea of the layout.
 

·
Registered
Joined
·
75 Posts
Discussion Starter · #2 ·
Sorry guys I couldn't figure out how to attach the file, graphs and photos. Figured out graphs and the file. But still says the pics are too large. I'll post pics as soon as I figure it out!! Sorry for the delay!!
 

Attachments

·
Premium Member
Joined
·
1,562 Posts
Your work paid off!

This is a very good result. It is very common to have a null in the bass range. About the only way to avoid that is with 2 or more SW and careful placement.

My only comment would be that possibly there is a boost filter working in the 90Hz null area that is pushing up the region 2-3dB from 60-120Hz? Even if there is, it is not a significant issue. If there is filter there, it may be a little better to reduce the boost so that region is a little flatter. The null itself is will not be helped by EQ anyway so the filters should ignore that feature and focus on smoothing the region surrounding the null. In my experience there will not be a significant sound quality problem with a very narrow null such as this. I only mention it in case there is a significant boost there to get this result. It is best to minimize the amount of EQ and also avoid any sharp filters.

Again, This is a great result, so any further fine tuning will not be significant.

Well done. :sn:
 

·
Registered
Joined
·
75 Posts
Discussion Starter · #4 ·
Thank you for the kind words!! The eq is audessey xt32 that comes built into the Onkyo 929. I used mainly placement(lots of moving- checking- rechecking- more moving), some diy absorbers, REW, and tons of patience. Got as close as possible to the goal and let xt32 do the rest. The surprise for me was the 40hz x over setting from xt32. I tried 60, 80, and 100hz for the mains- post xt32 and the results were loss in 90-120-150hz. All multiples of 30. I then noticed the only frequency lingering after 200 milliseconds in the waterfall was around 30hz. Which makes me believe the two issues could be related!??! I just don't have enough of an understanding at this point to draw any conclusions!! Was hoping some of you more experienced guys could lead me in the right direction!! Your post really gives me some relief!! I was worried I'd need to chase the 90hz dip for who knows how long to correct it!!!
 

·
Registered
Joined
·
75 Posts
Discussion Starter · #5 · (Edited)
OK, got the picture issue sorted out! These are rough, but should at least give an idea of placement!! I tried the short wall. Stacked in front corner. Stacked in rear corner. One in front corner and one in rear corner. This way is the most symmetrical and has given the best results to date. One curtain leads to a walk in closet and the other curtain leads to another slightly larger room. The crown amps and the xv15's are coasting at full reference.... and believe it or not the monitor series Polks aren't flinching in the least bit either!! Center(via crown xls) and rears(via 929)at 80hz(not used in the graph.. It was dual sub's and both towers(via crown xls) @-25db on the 929 and 40hz xo per xt32) next will be to check upper frequencies!!! I'm a bit hesitant as I'm sure it will become an entirely new mission!!! The testing gets a bit old at times... buuuuuut when you fiiiiinally see a decent graph and hear what you've been missing hidden behind all the boominess that you mistakenly thought was power/bass... I have to say its an incredibly awesome feeling!
 

Attachments

1 - 5 of 5 Posts
Top