Impedance - what is it in speakers?
Impedance is the complex resistance of an electrical circuit consisting of a resistor, capacitance and inductance, which acts when high-frequency alternating current enters the input of this circuit. Depending on the values of capacitance and inductance, the impedance of the circuit changes. At low frequencies, the active element (resistor) has a greater influence. At high frequencies - reactive elements (capacitance and inductance).
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Speaker impedance, which parameter to choose
Acoustic systems consist mainly of power amplifiers, frequency crossover filters and loudspeakers.
The bandwidth is 20-20,000 Hz. Power amplifiers are broadband and divided by frequency range.
- Low frequency (20–300 Hz).
- Mid-frequency (300–5000 Hz).
- High frequencies (5,000–20,000 Hz) belong to the 3-band class.
2-way amplifiers have two frequency ranges: LF-MF and HF. The input signal is distributed by filters across frequency channels and fed to the corresponding amplifiers.
To calculate crossover filters, radio amateurs need to know the input impedance at different frequency ranges. For low frequencies, the active impedance of the loudspeaker is 4 or 8 ohms. The impedance can be taken to be approximately 10% of these values.
You can measure it by connecting an audio frequency generator tuned to the crossover frequency (not lower than 6 kHz) through a 1 kohm resistor to a loudspeaker. The ratio of the voltages across the resistor and loudspeaker will show the desired value. The impedance of the high-frequency head is determined in the same way.
Features of connecting sound speakers
Connecting several speaker systems to a signal source is carried out in a serial, parallel and parallel-serial manner. Accordingly, the speaker group parameter is calculated using Ohm's Law. The labels and operating instructions for speakers and headphones indicate their resistance (4, 8, 16 ohms). If your speakers are not new, the instruction manual is lost, or for some other reason the resistance of the speakers is unknown to you, you can measure it with a multimeter. What it is? This is a special device for measuring this parameter.
Having freed the speakers in the speakers from the equipment, measure their resistance. The multimeter will show slightly lower resistance values close to the standard ones.
