. Elements of acoustical engineering. Electro-acoustics; Sound. 136 DIRECT RADIATOR LOUD SPEAKERS seen that the response at the high frequencies is improved. This system tends to drive the cone at constant velocity for constant signal voltage input. Therefore, the response will fall off below the point of ultimate resistance, because the radiation resistance falls off 6 db per octave in this range. See Fig. The response may be made uniform with respect to frequency by compensation of the input to the system. A feedback system employing an amplifier, loud speaker and microphone is shown in
. Elements of acoustical engineering. Electro-acoustics; Sound. 136 DIRECT RADIATOR LOUD SPEAKERS seen that the response at the high frequencies is improved. This system tends to drive the cone at constant velocity for constant signal voltage input. Therefore, the response will fall off below the point of ultimate resistance, because the radiation resistance falls off 6 db per octave in this range. See Fig. The response may be made uniform with respect to frequency by compensation of the input to the system. A feedback system employing an amplifier, loud speaker and microphone is shown in Fig. If a pressure operated microphone having uniform sensitivity with respect to frequency is used the response characteristic of the loud speaker will become more uniform as the amount of feedback is increased. Nonlinear Distortion. — Acoustical and electrical networks are assumed to be invariable; that is, the constants and connections of the network or system do not vary or change with time. In one type of variable-circuit element the variations which occur are controlled by out- side forces which do not appear in the equations or statements of the SUSPENSION fM EQUIVALENT CIRCUIT. FREQUENCY IN CYCLES PER SECOND Fig. Cross-sectional view of the vibrating system of a dynamic loud speaker mounted in a large baffle. In the equivalent circuit: w^c the mass of the cone and coil, w^ and rjv/A the mass and the mechanical resistance of the air load. Cms the compliance of the suspen- sion. Jm the mechanical driving force. The equivalent circuit indicates the effect of the nonlinear element Cms- The graph shows the distortion frequency characteristics for inputs to the voice coil of 2, 5 and 10 watts respectively. problem. In another type of variable-circuit element, the variation is not an explicit time function, but a function of the current and its deriva- tives which is flowing through the circuit. The outside diaphragm suspension is an example of the latter
Size: 2200px × 1136px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionameri, bookcollectionbiodiversity
