The measurement is taken in-room at 1 meter distance from the tweeter and gated around 3,6 ms if I recall. 400 hz steep crossover.
Initial impression is that the driver sounds way smoother than the D2430k but with more "attack" and sting in transients. There was always this harshness with the D2 that I couldn't get rid of no matter how much I tried with EQ. An annoying amount of sibilance with not enough body and weight, very possibly because of the strained performance below 1500 hz.
Straight off the bat I could hear a remarkable difference in those two areas with the 4015Be (truextent membranes I suppose) but I haven't had time to adjust in a decent balance in the frequency response due to waiting for L-pad and protection caps. I'll update as we go along.
I have some questions, though;
- How low should I/can I cross the tweeter? I asked 18sound directly because they recommend 900 hz crossover. They said that recommendation is based on the professional area with the nominal power rating stated as 140w nominal.
Lowering to 700 hz would be no problem but would lower the nominal power rating to around half, or 70w.
I'm not sure what that means in practical terms. With EQ to flatten the response I suppose you lower the efficiency to around the same as the reference point, say 700 hz in the raw response, and need to calculate spl per watt based on that?
If I assume something like 100 dB sensitivity after EQ I would be able to reach 110 dB peaks at 12 feet with 70 watt without destroying stuff? Calculator here;
https://myhometheater.homestead.com/splcalculator.html
- Advice on how to determine crossover slopes and timing? It's really difficult to get good and accurate measurements in the 700 hz area in-room and it's a real struggle to drag the speakers somewhere outside to measure.
- Experiences with high vs low crossover with truextent in terms of sound quality? To my ears it sounds like the 4015be sounds clearer and more dynamic above 650 hz than the 2216nd woofer does. Might be delusional, but that's my initial impression.