# Still learning REW, but more graphs...



## boarder1995 (Mar 28, 2008)

Ok, I'm still learning REW and need to keep studying, but I figured I'd post some old graphs while here at work, then I'll get some updated ones once I get home today. I'm starting to work on waterfall graphs and possible room treatments, so obviously I really need to get up on what I'm seeing measurement wise before implementing any sort of room treatment solution. I've got dual Ultras located in the front of the room right now and things look pretty good. I don't have any eq or built in eq-ing on my receiver (old Denon unit). Ignore right now above ~80Hz, since my mains I think were still connected and they have a hard time below 100Hz with my receiver's fixed 80Hz crossover slope (another issue). The room is ~15ft wide x ~20ft long x 10ft tall with all ceramic tile floor and area rug and no room treatments (yet). I originally took numerous location measurements to verify fairly even room reponse, but inintally here I'll only focus on one seating position (mine!) with the graphs. So, here's a first look at frequency response and waterfall graphs from a room measurement I took a while back.
response graph:







No smoothing, so it looks pretty good (to me). Now the waterfall image...







Look at all that ringing! So, I think I've got some work to do. Time range is 600ms and window is 300ms. I wonder if I'll really be able to do much with the low frequency ringing with room treatments...32Hz, if I'm reading the ringing right, is pretty low to acoustically corner treat.

I posted last week in the acoustic forum with some initial arbitrary panel placement images and subjective listening and was amazed at the changes that took place (some good and some not), so I'm anxious to get more plots, including up through the full range to look at ringing with and without room treatments eventually. I know from listening at home versus a B&W dealer I've started frequenting (is that safe?) I've got a VERY live room and really like the more damped sound in the dealer's treated rooms I think. So, perhaps some of my inital room treatments might better be suited for mid and treble acoustics. We'll see.


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## boarder1995 (Mar 28, 2008)

Here's a "zoomed in" waterfall graph from data above. Time range 350ms, window 300ms.







Perhaps this better shows more ringing modes? 20, 30, 50, 60, 70 and 90Hz.


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## Wayne A. Pflughaupt (Apr 13, 2006)

> Look at all that ringing!


That's about standard for a room - actually better than average. Of course you know that bass traps are the only treatment for truncating bass ringing?

Regards,
Wayne


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## boarder1995 (Mar 28, 2008)

Thanks Wayne. So, perhaps it's not that bad? As far as reducing the ringing, that's how I understand it, you can't eq it out, you have to treat it acoustically.

I took some more measurements at home during lunch (this isn't a sign of addiction, is it?) and got some different results that I need to graph and possibly post. I've got my subs hooked up a bit different, so my upper subrange is hurting a bit.


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## brucek (Apr 11, 2006)

> As far as reducing the ringing, that's how I understand it, you can't eq it out


Sure you can, if the filter matches the mode fairly accurately... Filters also act in the time domain, the same as modal peaks.

brucek


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## Wayne A. Pflughaupt (Apr 13, 2006)

Not really seeing any modal peaks in those graphs, though...

Regards,
Wayne


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