Originally Posted by Pete_Hsu
The frequency response of 15-200Hz (+/-2dB) that we measured outdoors is in the ported max extension mode (ie. one port plugged, Q = 0.7, operating mode set to 'EQ1').
The max clean CEA2010 peak output capability that we measured outdoors and was referenced earlier is in the ported max output mode (ie. both ports open). Note that the frequency response we measured outside in this mode is +/-2dB from 20-200Hz (Q = 0.7).
The final EQ'd frequency response can be whatever the designer chooses to be, but the max clean CEA2010 peak output capability will not change irrespective of how the final frequency response is shaped by the designer.
Absolutely, I can ask Dr. Hsu about posting some frequency response graphs on our website. I would like to take the unit to a park to get graphs that are as ripple free as possible, and we can post them.
Always good to see you.
Yes, I got the FR and CEA numbers. It's the highlighted part that was my focus.
My point was that most every reader of those posted specs did NOT get that, at the max #s level, the FR changes rather drastically, which is a normal phenomenon when porting LTD's favorite drivers, but not generally understood.
In order to realize the max numbers above the knee, the EQ'd FR flies out the window. IOW, the sub, at maximum output and assuming properly operating limiters, will perform like a typical pro sound "subwoofer". If you post the max CEA #s and the EQ'd FR together without that distinction, it's misleading.
Since I've built sealed L/T'd subs for many years, I'm well aware of the fact that the native FR and the max output FR are not the same. The question is where do the 2 begin to part ways, which helps with how many are needed for a particular rooms transfer function, etc.
Maybe if part of the CEA standard was to plot the max CEA curve on a standard graph, the numbers would immediately be put into context by illustration.
The traces are approximate from what you've posted thus far. I appreciate the gesture to post the actual measured responses.
Put it this way; it was easy for me to see at a glance that there was a wider than normal disparity when the numbers were posted. Thus my comments, which I would not have brought up if you hadn't popped into the DIY section.
Of course, I'm sure you're aware, the protestations of a couple of your apparently offended faithful notwithstanding, that I'm simply making an observation, based on your posted data. No harm intended. The sub looks to be another great product in a long list of them.