As a lover of sub heavy music production, I always strive for the lowest feeling, hardest hitting sub frequencies. The lower the frequency the more powerful it feels. But how low is too low?
The range of sensitivity for the human range of hearing is typically defined as 20Hz to 20kHz. When putting your ears to the test, you will notice that it can be impossible to detect frequencies as you approach the extent of this range. Naturally, your ears will go through some deterioration depending on how well you protect your ears and this deterioration begins with the higher frequencies first. This is not the case for the low end. Low frequencies begin to diminish not because of our hearing but because of playback systems themselves. Low frequency wavelengths are extremely long in length and require big speaker systems to carry them. In fact, even the biggest of systems that you find at outdoor music festivals will bottom out around 30 to 35Hz. This is an important distinction to make so that you don't waste valuable headroom trying to produce frequencies that low.
The note D produces a frequency of 37Hz, the next lowest note is a C# and it produces a frequency of 35Hz which is the cutoff for most systems. Staying above C# is a good way to ensure that even the lowest of sub basses will be reproduced on most speaker setups.