Originally Posted by J_Palmer_Cass
I realize all of that. However, in effect all Notny shows is a comparison of how each subwoofer (sealed and ported) plays 18 Hz and above. My system will probably look the very similar to those waterfalls in that part of the spectrum!
Do you see any difference between sealed and ported waterfalls?
Originally Posted by MKtheater
I agree but the spec lab will show decay, THD, SPL, and extension. Decay could show up as not a flat response. Bosso would be better to answer as he has experience with these type of comparisons.
It will also show all frequency response non-linearity. When, for example, there is a G2G comparo of different subs, what a given sub may 'hit' in dBSPL will have everything to do with that subs FR at the mic as it corresponds to what the content of the scene is. If, for example, there's a sound effect centered at 40 Hz and one sub has a FR peak @ 40 Hz, it may 'hit' a higher # vs other subs and the SL will show why.
Rob has a superb system, but he has chosen to roll off above the Irene scenes bottom fundamental. Thanks to Rob for posting the data. I've been wondering why no one has done this over the years I've been asking for it. It completely eliminates the controversy surrounding the "my system handles that scene with no problem" comments.
Ask Max and/or Nube how to input a correction file for SL if interested in this exercise. My measurement system requires no calibration file to 4 Hz, so I leave it at that when mic'ing scenes through SL.
The top graph is a digital measurement off of an AVRs SW output.
Since there's no 6 Hz fundamental from either system, there's of course no 2HD at 12 Hz, but the 2HD of the 18 Hz fundamental shows higher THD from the ported system. In this case, it's no doubt masked completely, but I seriously doubt JPC's system (and many other member's as well) would show this kind of performance at reference level, and especially at the +10dBRL level.
As far as the experience of Irene as a listener, I've commented often over the years that this scene is not a good one to eval ULF because of the steady state nature of the fundamentals, the number of simultaneous fundamentals and the fact that the spread of fundamentals are odd-order from 6 Hz to 122 Hz (roughly). It's higher value is in seeing the extension and even order HD of your system at the seats when the system is pushed to whatever your listening level is. Most members comment that they never listen at RL. Most prefer -10dBRL to -15dBRL. But, if you run your subs hot then, for the purposes of this exercise (a SL graph to 120 Hz), you are listening at RL when your MVL is at -10dB.