View Full Version : Is Baffle Step important...
11-16-2010, 12:37 AM
when you measure the drivers on and off axis in the enclosure to be used?
I understand the concept completely, but I don't worry about it, because I measure in the drivers enclosure that will be used. If it matters, I try to use a crossover point before the lower range drivers begin to drop off. Am I still missing something that can sabotage my builds?
11-16-2010, 12:52 AM
If you're measuring your drivers in the final enclosure then your measured responses already include the real baffle step effect. At least on the access you're measuring on.
11-16-2010, 02:53 AM
If you measure near the driver (maybe half a meter) does the reading still show the baffle step?
11-16-2010, 03:46 AM
In the extreme nearfield, i.e., 0.25", where woofer low-frequency response is typically measured, the cone itself is the baffle, the measurement is 2Pi, and there is no baffle step, implying that at some distance, there is a transition region in which baffle step emerges. Vary the mic distance in Jeff's Baffle Diffraction Simulator to see where that occurs, maybe....
I'm not an expert, but, I do the same thing you're doing with good results for BSC.
The fundamental idea is that when wavelengths are large compared with an object, the exact shape of the object becomes unimportant. The application in this case is the measurement distance vs. baffle size. The baffle size determines the onset wavelength, and you want to be several times that wavelength away. As zilch notes, at 1/4", all practical drivers are on infinite baffles.
As long as you're several baffle widths away, you should capture your BSC requirement in the woofer FR. BDS may give you a more precise answer; this is only a "rule of thumb."
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