I received my shiny (erm, matte, actually) new F15-DS1505 today
Much faster than I expected due to Brian shipping super-fast, and UPS actually delivering a day ahead of schedule (how often does that happen?!).
After wrestling the beast out of the boxes (super-sturdy packaging, BTW), and letting it warm up some, I started on the frequency response measurements. And here's where I hit a head-scratcher pretty much right away:
These are all near-field (125mm), on the LFE input, and PEQ-off, in order to try and get the sub's inherent response as closely as possible. Below about 45Hz the response is exactly what I expected. But higher up there seems to be a wide hump, let's say from around 60Hz-180Hz, with a peak around 120Hz at around +6-8dB.
I haven't found that feature in any other frequency response graphs, including this one from Brian:
I have tried various things like moving the sub and mic to other positions in the room, but that feature is always present.
So far I've had a few ideas as to what might causing that, but with no evidence for any of them:
- room interaction, in-spite of being a near-field measurement
- DS1505 instead of DS1501, and having different inherent frequency response
- response will even out after breaking-in
Has anyone else seen behavior like that before, and/or have any good explanation for it?
Since the hump is largely above the crossover point, and I'm going to use Audyssey MultiEQ XT32, I'm not very worried about it yet. More an issue of curiosity, and wondering if I should wait for it to break in more before doing the tedious EQ work.
Thanks in advance for any thoughts,