Negative feedback amplifying circuit having voltage negative feedback and current negative feedback circuits

A negative feedback amplifying circuit comprising:

• (a) an amplifier having positive and negative inputs, the output of said amplifier being coupled to a load comprising a speaker;
• (b) a resistor connected in series with said speaker;
• (c) a voltage negative feedback circuit for feeding back the output voltage of said amplifier to the negative input of said amplifier;
• and
• (d) a current negative feedback circuit for feeding back a signal, which is a function of the potential difference between both the ends of said resistor, to the negative input of said amplifier, said voltage negative feedback circuit having a frequency selection characteristic having a dip at a specific frequency which is equal to the minimum resonance frequency due to the mechanical impedance of said speaker, and said current negative feedback circuit having a frequency selection characteristic having a peak at said specific frequency.