The frequency at which foam is effective is dependant on its thickness, due to the wavelength of the sound at that frequency. You could not make a foam tile an inch thick that is effective to 20Hz because an inch is neither here nor there compared to the wavelength of 56ft. It is very significant to the wavelength of 1kHz of 1.12ft or 10kHz wavelength of 1.3 inches.

That is why for effective LF absorbtion in a domestic environment (where several feet of foam may not be acceptable), resonant traps have to be used.