Understanding Frequencies

[Mylo]

I’m having difficulty wrapping my head around frequency ranges and how they relate to play back.

Here is the setup:
I have a digital piano that I’m running through an amp which is connected to a pair of 20+ year old Monitor Audio S8. These speakers have a frequency range of 35Hz-20KHz +/-3dB.

When I play the lowest key on the keyboard (A0) which has a frequency of 27.5Hz my system has no problem playing it loud and clear registering at 70dB on my SPL meter @1Meter. My tuner on my iPad shows the proper note being played at 27.5Hz.

Now when I play my 27Hz test tone through the same setup I can barely hear it and it doesn’t even register on the SPL meter. And this part makes sense. The speakers have a low end roll off of course so while they can play at 27Hz it is why down like -30db. So how do the speakers play A0 at 27.5Hz nice and loud?

I’m having trouble understanding how all this relates. Any help in gaining understanding here is appreciated.

 

[mep]

You are not hearing the fundamental 27.5 Hz tone from your piano over your speakers. You are hearing harmonics of 27.5 Hz. The first harmonic would be 55 Hz which you would hear nice and loud.

 

[Mylo]

Harmonics… that’s what I was missing. Thanks. So when I play an A0 on an acoustic piano I don’t just hear the fundamental I’m actually hearing all the harmonics as well? And I hear something much higher in frequency because it is the fundamental frequency combined with all the harmonics?

So if I’m designing a speaker system for my digital piano I don’t need a super low end of say 20Hz to faithfully reproduce A0, an f3 of 35Hz should be fine.