JBL 4429 and "deep bass" don't belong in the same sentence. I worked at an audio store in SoCal several years ago, and after playing some test and demonstration records through the typical JBL formula--horn plus oversized ported woofer, the frequency sweeps clearly showed that these big 12" and 15" woofers were starting to roll off at 100 Hz, which would explain why they're down 6 dB at 40 Hz.
Most of the perceived bass on this design is overtones. It's mostly midbass thump with little true extension. It sounds impressive on '70s rock and pop, but less so with deep synth tones, and the constant barrage of high frequency sizzle, blaring midrange, and upper bass thump gets fatiguing, even on the music it does fairly well.
And acoustic classical music easily shows its shortcomings.
Most of the perceived bass on this design is overtones. It's mostly midbass thump with little true extension. It sounds impressive on '70s rock and pop, but less so with deep synth tones, and the constant barrage of high frequency sizzle, blaring midrange, and upper bass thump gets fatiguing, even on the music it does fairly well.
And acoustic classical music easily shows its shortcomings.