抄録
The jump phenomena in loudspeakers have been discussed in only a few literatures. When the jump phenomena occur, the amplitudes of loudspeakers would become suddenly very large and the greatest distortions would occur then. So these phenomena are deemed very important in practical use. In this paper, the jump phenomena in loudspeakers are treated theoretically and experimentally. If a voltage, Vcosωt, be applied across the voice coil, the resulting motion is assumed to be described by the equations Mx+Rx+sx+qx^3=Bli (1) R__ci+Blx=Vcosωt, (2)where M=mass of the cone and coil and air load, R=mechanical resistance, s+qx^2=stiffness of the suspension system, B=magnetic flux density in the air gap, l=length of the voice coil, i=current in the voice coil, R__c=d. c. resistance of the voice coil. The maximum applied voltage free from the jump phenomenon has been calculated by using the above equations. The result is V^2=16r^3/(27ck^2){9ar+9r^3+(a+3r^2)√<12a+9r^2>, (3) where r=R/M+<B^2><l^2>/(MR__c) a=s/M c=q/M k=Bl/(MR__c). The following conclusions have been obtained from the results of equation (3) and some experiments. In order to reduce the occurrence of the jump phenomena, (1) it is absolutely necessary that the linearity of cone suspension system is very good, that is the value of q in stiffness s+qx^2 is minimized; (2) it is necessary that the values of mechanical resistance R and s in stiffness are large; and also (3) it is desirable to lessen the value of the mass M.
