幹嘛唱到14Hz？

http://www.rythmikaudio.com/faq.html#14hz

The simple answer is yes. The more accurate, more complicated answer is that it depends on the music you are listening to. On dance mixes and music with extremely high bass contents, one does not need 14 Hz extension because of what is called the "masking effect". The masking effect occurs when a high amplitude signal is present simultaneously with other smaller amplitude signals. The perceived loudness of the smaller amplitude signal is drastically reduced. In addition, human ear's sensitivity decreases in the lower frequencies. Therefore for this type of music, one may even want to set the extension setting higher with lower damping factor setting (in our A350/A370 amps). That will make the bass sound clean (by removing ambient information) and punchy. It essentially allocates more amplifier power to the signal that we hear and care about most. On the other hand, when no such signals are present (for example, in jazz, solo and other types of music) and masking effect is not strong, one can clearly hear the difference that a 14 Hz extension makes (vs say 28 Hz extension). It is not a difference that will have you jumping out of your seat say "there's the bass". Rather it is an improvement in two areas: ambience and dynamics.

Rythmik很實在的說，如果你聽的是那些乒乒乓乓低音一堆的音樂，因為遮蔽效應，那麼低的頻率其實你聽不到；
若是音樂中的低頻比重不多，那你就會聽見；
但，幹嘛要聽見呢？

因為空間感

Ambience: good recordings normally capture a lot of ambience information which is predominantly low frequency signals. It is generally agreed that the lower the sub plays, the deeper, taller, and wider the sound stage becomes (or one may say open and spacious).

這與我的經驗相符，低頻越好，空間感越漂亮～音場越是高深遠。

還真湊巧，今天就在廖老哥的系統驗證這點，
二隻15"超低音一開，音場立刻放大！

深度多了不只二倍，也顯得比較寬而高，真實很多，超神奇啊～
弄的我也好想買隻Rythmik...
這超低音負責的頻段其實不多，50Hz/-6dB到20Hz而已（DSP分頻是我搞的），效果竟然如此大哪...

我真的要說，各位啊，要音場又深又遠，務必加隻能唱到20Hz的超低音啊...