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Here's a reading I took after adding just one floor to ceiling corner superchunk bass trap in my room and then a second reading after adding two more floor to ceiling corner superchunks plus one front wall-ceiling superchunk the entire width of the room. I'm barely an amateur with this stuff, but it looks like I'm not seeing much of a difference. Can anyone comment on these two readings?
It would have been best to do a no traps/all traps comparison, rather than one vs. three.

It’s a bit difficult to compare the two because your second reading appears to be at a significantly higher SPL level than the first. Note in the blue graph that response in the 25-35 Hz range is a few dB below the 96 dB line, while in the green graph response in that range is peaking over 96 dB. This is going to make the second graph look worse in that range, whether it is or not. Consistent SPL levels from one reading to the next is mandatory for any kind of meaningful waterfall before/after evaluation.

That said, I do see some improvement in the second graph (looking at the first 300 ms pair). At 80 Hz, SPL levels in both graphs somehow look consistent despite (as mentioned) what’s happening below that point. Not sure, but that possibly could be a result of the traps. But notice in the green graph that decay is notably improved at 80 Hz compared to the blue (at least down to 45 dB, which is a bit high for many residential rooms). That’s most likely from the traps.

Also notice the far right of the graphs, in the range between about 150-200 Hz. Note that in the green graph the signal level is significantly higher, yet the decay time is about the same as the blue graph. All things being equal, the higher SPL level will show longer decay. So that definitely indicates an improvement in ringing.

Personally, I prefer the linear scale for analyzing waterfalls. Above 40 Hz, the logarithmic graphs scrunch everything up like an accordion. The linear graphs spread things out, which makes them easier to analyze.

Aside from the graphs, how do things sound? The traps should make the bass sound tighter. They may also be working well above the 200 Hz cut-off point for these graphs, which certainly can’t be a bad thing.

I agree with brucek’s recommendation for equalizing. Traps mainly reduce signal decay times; they can only do so much for room modes, especially if you have only a few of them (traps, that is). Plus they are increasingly less effective the lower response goes.

Regards,
Wayne
 
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