Depends on some people's tastes. You'd be surprised how many people dont care about hearing notes lower then 30 hz, especially classicals, latin, jazz, country, rock and blues where anything lower then 35hz is pretty non existent for the majority of songs and tuning that low really reduces the loudness of the upper frequencies that make those songs shine. Each sub can be musical at higher tunings but enclosure design has a lot to do with that. You can claim its flat but in a direct side by side comparison, its a pretty steep drop in the upper frequencies. When it comes to enclosure design, there's always a tradeoff.