Note that there are many implementations of all-pass filters (and phase shifters, and time delays...)
Note that there are many implementations of all-pass filters (and phase shifters, and time delays...)
Is this more correct?
It is not a question of being correct, but easier to anlyse. But I was addressing the frequency response graphs, not the waterfall one's - apologies if I was not clear.
But it seems that others settings or things have changed besides the room treatment between the measurements. This will make difficult to compare the before and after.
Yeah, I'm not sure why there is such a difference. REW doesn't seem to have a way to overlap the two graphs that I can see, post measurement.
But here is the adjusted graph:
You can use the add offset to data in the Controls Window to move one of the graphs up or down. But IMHO the differences shown can not be due mainly to room treatment - my first guess would be that the system in green would sound better than the one in blue!
Unhappily the WBF experts are not chiming. We need them!
Actually, IME most people prefer a curve tilted toward the low end like that...
I had to indeed turn the volume DOWN on the woofer amps after installing the Modex Plates and RealTraps, and yet the low end is still quite a bit higher in amplitude than it was prior.
Yes, and it's a common misconception that adding bass traps reduces the level of bass frequencies. Peaks are typically 6 dB or less, but nulls can be 30 or even 40 dB deep. So adding bass traps raises the nulls more than it reduces the peaks, with the net result being more bass. At least in most rooms. In a square or cube room the peaks might dominate, so adding traps would lower the overall level more. The good news is bass traps do whatever is needed! That is, they lower peaks and raise nulls. (Bill, I know you understand this!)
--Ethan
Here’s another example along the same lines that someone posted at HT Shack last month. Three measurements – left and right corners, and center-of-wall. I don’t think I have to point out which trace is the center-of-wall, do I?Was able to move the subwoofer and measure the effects. Tried ~1/2 the distance up the long wall (12 ft from front wall) with the woofer firing into the center of the room. No substantive change. Previously tried the sub in both front corners of the room. Again, no significant change.
As recommended here, moved the woofer to the back corner of the room. This had a big impact on the null- in a positive way.
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