[s_cervin]

Just downloaded Room EQ wizard and am using the ECM8000 measurement mic.  I've got a usb pre coming to use as well.  When running the measurements I was doing each channel seperate.  I do have some treatments in the room (2 2x4', 4 2x2', and 2x4' 2" thick knauf).  I now need to work on a couple bass traps that are alright w/ the looks.

Now if I could only post the measurements.  No additional options to attach.

http://www.audiocircle.com/index.php?action=gallery;area=browse;user=39399

[bpape]

I'll be happy to work through it with you .  Please retake the measurements with both channels (use a Y cable) and set the range from 20-300 with no smoothing so we can see what's going on.

Bryan

[s_cervin]

I'll be happy to work through it with you .  Please retake the measurements with both channels (use a Y cable) and set the range from 20-300 with no smoothing so we can see what's going on.

Bryan

I planned to work in steps and hit the bottom end first.  This was just a first crack and the ETF site mentioned measuring each channel.  I had previously measured both and didn't get that funny inverted point at 70 Hz.  I'll do what you suggest and go from there.  Looking at it I see what looks to be 1st room mode at 45 Hz and second around 90 Hz.  Does anyone do anything with the higher frequencies?  I know some is the speaker response which is a rolled off in the highs, but is the rest modal ringing?? What stinks is I have to use the headphone out on the laptop.  If anyone can help me through using the SPDIF out on my HP it wouls be greatly appreciated.  Tried messing with the soundcard settings and nothing.

Thanks for the help.  I plan on getting some OC 703 at some point. 

[bpape]

Doing both channels gives you more reality.  Doing each individual channel is still useful to identify any boundary related issues caused by out of symmetry situations with regard to the speakers and the side walls.

Headphone out will work OK - like I said, just use a Y cable to split the single signal to both amp channels for measurement.

The higher frequencies will be spiky in every room - just the way it is but they're close together and general reflection and decay time control will help tame things.

Bryan

[ctviggen]

Modal ringing can only be determined by using a waterfall plot.  Does this software support waterfall plots?  Also, I think the highs would be helped through broadband absorption and diffusion.  The tricky thing is that the effects of diffusion are a bit hard to measure. 

Have you tried moving the speaker with the funky curve?  Also, some of these systems are prone to error, meaning that you could take one measurement and then another and get two different, but similar, curves.  See if your system is like that.

[bpape]

REQ will plot waterfalls no problem.

One can model the theoretical decay times  down to about 100Hz pretty easily if you know how it's built (single or double drywall, insulation in cavities, floor is concrete or wood system, etc) , what's in it for furniture, people, windows, doors, etc.  While it's not perfect, it can certainly get you to the 95% solution by adding appropriate amounts of absorbant/diffusive materials to the models and see where you stand in relation to the target times - which are determined by what the room will be used for (2 channel, multi-channel, etc.)

Bryan

[s_cervin]

Here is the new plot:
http://www.audiocircle.com/index.php?action=gallery;area=browse;album=969&pos=4

Here are a few room pics:
http://www.audiocircle.com/index.php?action=gallery;area=browse;album=969&pos=2
http://www.audiocircle.com/index.php?action=gallery;area=browse;album=969&pos=1
http://www.audiocircle.com/index.php?action=gallery;area=browse;album=969&pos=0

SC

[bpape]

Looks pretty typical - though not too bad.  Some likely modal dips and peaks.  Treatment will help a few db.  Also, are you measuring only at seated head position and with both channels?

Bryan

[s_cervin]

Looks pretty typical - though not too bad.  Some likely modal dips and peaks.  Treatment will help a few db.  Also, are you measuring only at seated head position and with both channels?

Bryan

Yes.  How much do you think getting the treatment I already have off the wall a few inches help?  I need some bass traps, but don't have the room in the corners.  I'll just have to get creative I guess.  I plan to take another measurement with all the treatment I have out.  Just to see where it is helping. 

I'm an ME that deals with body bending/torsion and other modes.  I'm usually looking at crosscar and fore/aft modes.  This is some fun stuff!!

[bpape]

Don't limit yourself.  Think of horizontal corners where the walls meet the ceiling

Bryan

[rcarlton]

s_cervin,
A nice resource to help you really use the REW is located at another forum at http://www.hometheatershack.com/forums/bfd-rew-forum/.