Warning. Play tones at extreme volumes, can mechanically endangering your loudspeaker.
You can smoothly change the frequencyPlay
Fs - Resonant frequency of loudspeaker moving mass (in free air). Resonant frequency is one of the primary measurements for the popular Thiele/Small parameters
Fb - bass reflex resonance frequency.
Why is Subwoofer Resonant Frequency Important?
Speakers with much lower resonant frequencies are generally low in output and have a narrow range of frequency. Ensuring that your speaker is resonating at the correct frequency is important for the following reasons:
Prevents Ringing: Resonating at the correct frequency will prevent your speaker cabinet from ringing. When audio is played through a speaker at the resonant frequency, the speaker cabinet will radiate that sound. If not, the combination of sounds from the moving parts and the stiffness of the suspension will affect the overall frequency and cause ringing.
Frequency Response: A subwoofer resonant frequency determines how well it will perform with low frequencies. As an example, a subwoofer that operates at 40Hz will have deeper, bass tones than a subwoofer that operates at 60Hz for example.
Most subwoofer boxes take advantage of this concept
How to find speaker resonant frequency?
The frequency at which the combination of the energy stored in the moving mass and suspension compliance is maximum, and results in maximum cone velocity, at this point, impedance of the loudspeaker is maximum. A more compliant suspension or a larger moving mass will cause a lower resonance frequency, and vice versa.