Originally Posted by noah katz
But do people think midbass punch is predictable just w/measurements?
I hate to venture into "fast bass" territory, but if it were that simple you'd just need to EQ up any rolloff, assuming enough output capability.
Yes, midbass punch is predictable with just measurements. Of course, this assumes a minimum of performance requirements are met, but take any subwoofer that's flat through the crossover and A/B it with and without a 40Hz HP filter.
Looking at the Tumult MKI graphs above, you see a 10dB drop from 40Hz to 100Hz. That's 7dB/octave. If you use a typical 4th order LP and cross at the typical 80Hz point, you're LP side is better than 5th order vs the typical 2nd order HP, which is made shallower by room gain going down.
That's not likely to be fixed by EQ. The 'fix' was to lower the crossover to a point where the driver was designed to be operated in. This left the midbass to the mains. Whether or not mains are capable, their placement restrictions almost always results in a wanting response in the 100-200Hz BW.
This lower crossover point requirement was reinforced by the audiophiles who insisted that any sub crossed higher than 40Hz would be localized.
The latest generation of XBl^2 HT subs (Tumult MKII, Mael-X, Shiva-X) employ shorting rings to lower inductance which allows for a higher crossover point.
But, any sub with an octave or 2 more extension will sound different from a pro sound driver. Efficiency has nothing to do with it.
Ilkka's sweeps of the Tumult MKI show a 10% THD limited output at 80Hz of around 92dB with less that 1dB of compression, but the CEA test result is 111dB at 80Hz. That's at 2M. At 1M, where all pro sound drivers list their 'specs' it would be 117dB.
That's plenty of clean output to judge midbass in a home. It just isn't realized when you lower the crossover point and try to match a Tumult with not-so-good mains.