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Discussion Starter #1
how do these look? any comments, this is quite a large room.
the waterfall looks reasonbly flat to me with no real reasonances,
there is a reasonance at 111Hz i think and also at 52 -
thanks in advance
 

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Use the graph limits button (near the top right) to set the SPL range to 45 ... 105dB, and the frequency range to 15 ... 200Hz. In the settings on the Analysis tab check that the "Spectral Decay Left" window is set to Hann. Tweak the Y axis slider so that the top of the back wall of the waterfall is just visible (usually a value about 50). Set both the window and the time range to 300ms.
 

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I think the reason you're finding it hard to read is that there is something not quite right about either the room or the test setup that is making your waterfall look, eh, not so good... if you truly have that much energy left in the acoustics after 300ms especially across that wide a frequency range, you'll need some serious acoustic absorption... but before we direct to the sub-forum for that kind of help, let's focus on making sure you're taking the measurements correctly...

To generate this waterfall you must've taken a sweep... please post that sweep with the same axis ranges as this waterfall (45-105dB=yaxis, 20-200Hz xaxis)... before you generate the jpg of that sweep, make sure to turn on the mic cal and soudncard cal curves, so we can get a feel for things...

EDIT: Also, before posting that sweep, switch the x-axis to LOG mode, post the sweep, and repost the waterfall that way, please.
 

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Discussion Starter #9
Hi thanks for the help - this is a very large recording studio live room, about
7x6x3 metres L W H, it was untreated (bare walls very reflective) when the measurments were taken,
the mic is a B and K measurment mic (omni) into a Tc soundcard -
does any of this info help?
i think i have sent in the jpg as you asked correctly
thanks again for the help.
 

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For the waterfalls select log frequency axis - use the button in the toolbar, third from the right to toggle between linear and log axis. The frequency range is also a bit wider than is useful, especially for a large room - use the button 2nd from the right to set the upper limit of the frequency axis to 200Hz.

There are some hefty peaks at 111 and around 50, certainly, and overall the response rolls off below 80Hz. Is there some kind of sub in the system or is this measurement just one of your monitors?
 

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Discussion Starter #12
hi John - Thank you for your help, this is just one monitor, no sub, i put the mic
at the mix position and the monitor at the intended position, it is a very large
room, so we are trying to find out where the resonaces are, and what areas
need treatment, i will change the view on the waterfall.
thanks again.
 

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To see the effects of placement it can be useful to use the RTA display on the Spectrum tab, that way you get live feedback on the response changes as you move the monitor or mix position. There is more info on the RTA display here. When using the RTA select "Pink PN" as the signal type on the REW signal generator and make sure the window setting on the Spectrum/RTA tab is set to rectangular.
 

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Guys, I'm new to using REW myself, but when I was taking some recent measurements of the response in my room, my waterfalls suddenly started looking all messed up like the OP's. If I recall correctly, it had something to do with zooming on the Y axis, and once I'd done it, no amount of zooming out could stop my waterfalls from looking like that.

I finally fixed the problem by deleting all my settings (I think there's a button that says delete settings and shut down, or something like that). Then I reapplied my settings (don't forget to include the cal files) and everything worked fine again.
 

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Guys, I'm new to using REW myself, but when I was taking some recent measurements of the response in my room, my waterfalls suddenly started looking all messed up like the OP's. If I recall correctly, it had something to do with zooming on the Y axis, and once I'd done it, no amount of zooming out could stop my waterfalls from looking like that.

I finally fixed the problem by deleting all my settings (I think there's a button that says delete settings and shut down, or something like that). Then I reapplied my settings (don't forget to include the cal files) and everything worked fine again.
Hmmm... unfortunately I'm still on the road and cannot confirm on my system... but there is definitely a known issue with the waterfalls when the freq axis is in LINEAR mode... but I believe it's always been recoverable, as in, goes away once switched in LOG mode...
 

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Well, I'm not seeing any problems on my system... since you seem to have a workaround I won't kill myself trying... perhaps I'm not sure exactly what I'm supposed to be looking for either...
If you're zooming around a bunch, it's easier to get back to where you were if you use the "graph limits" button rather than simply zooming back in/out... and make sure you didn't inadvertantly switch to LIN mode on the frequency scale...
 

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Discussion Starter #17
Thanks for all the help.
will post some graphs soon,
i think it was because it was in linear mode.
 
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