How low can you go?

So according to theory – and this is backed up by our own experience, too – go any lower than 20.6Hz (E0) and things will start to become inaudible – not only due to the limits of our hearing, but also often due to the physical limitations of the speaker system.

What does this mean in practice? Since basslines generally start and end in the key of the track, write a tune in the key of C#, and the lowest C# note you'll be able to produce is C# 1 (34.6Hz). Counterintuitively, if you transpose the whole track up three semitones to the key of E, you can hit that lower E0 note (20.6Hz).

Of course, you don't have to stick to the root note for your bassline. For example, if you're in the key of B, you'll get the weightiest, lowest note by occassionally dropping down to the low F# (23Hz), which is the fifth of B. Do whatever works musically, but know your low-end limits!