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As someone pointed out, the size of theaters makes loud ultra deep bass extremely hard. Two reasons, volume of the space requires more drivers to hit a given spl throughout the theater and they are large enough you are not getting any gains from reinforcement below the room’s lowest modal frequency.
I would be willing to bet you that with very few exceptions, most theaters bass rolls off starting about 40hz, as that is where most large sound reinforcement bass cabinets start to. Every time you cut the frequency in half, you have to quadruple excursion of the sub to get the same output. Also, having really deep bass at high output tends to mask the midbass, which makes it sound like less overall bass in the room.
I have never been in a theater that has any real output below 30hz. This includes the Chinese, Fox, and Egyption in Los Angeles and Dolby’s theater in San Francisco. In my own room I have a 7-8 db gain from 30 hz down to 15hz. Really deep bass isn’t heard, it is felt and feels like an earthquake as the room just shakes. I start to roll my subs off at 28hz, as it flattens my bass and actually makes it sound louder without the extra low frequency volume masking the 40-80hz range.
Finally, keep in mind that very few movies have significant sub 30hz output. There is a small group of them as well as a group of home theater buffs who pursue deep bass performance down to 10hz and below for those movies and some synthesized music. I think for the vast majority of people, aiming for high quality smooth bass down to 30hz is a better goal using multiple small subs rather than chasing that last little bit with a single large sub that may have ultra deep capability.
I would be willing to bet you that with very few exceptions, most theaters bass rolls off starting about 40hz, as that is where most large sound reinforcement bass cabinets start to. Every time you cut the frequency in half, you have to quadruple excursion of the sub to get the same output. Also, having really deep bass at high output tends to mask the midbass, which makes it sound like less overall bass in the room.
I have never been in a theater that has any real output below 30hz. This includes the Chinese, Fox, and Egyption in Los Angeles and Dolby’s theater in San Francisco. In my own room I have a 7-8 db gain from 30 hz down to 15hz. Really deep bass isn’t heard, it is felt and feels like an earthquake as the room just shakes. I start to roll my subs off at 28hz, as it flattens my bass and actually makes it sound louder without the extra low frequency volume masking the 40-80hz range.
Finally, keep in mind that very few movies have significant sub 30hz output. There is a small group of them as well as a group of home theater buffs who pursue deep bass performance down to 10hz and below for those movies and some synthesized music. I think for the vast majority of people, aiming for high quality smooth bass down to 30hz is a better goal using multiple small subs rather than chasing that last little bit with a single large sub that may have ultra deep capability.
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