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Here is a brief analysis of a typical audio setup and the parametric influence of loudspeaker cables on the resultant delivered signal. I will make a few assumptions for this first order analysis:
1. The loudspeaker is rated at 8 Ohms and is mostly resistive (not reactive).
2. The dominant impedance component for the speaker drivers is 6 Ohm resistive @ 1000 Hz
3. The Audio Power Amplifier in our system has a rated dampening factor of 25 into an 8 Ohm driver, meaning that its source resistance is around 0.25 Ohms, non-reactive at 1 kHz
4. The distance between the Power Amplifier(s) and the loudspeakers is 10 feet.
5. The cable connecting the Power Amplifier to the loudspeakers is 16 AWG zip cord (commonly found at any hardware store).
6. The resistance per foot is 0.004 Ohms per foot (each direction) making the aggregate resistance per foot 0.008 Ohms per foot.
7. The inductance per foot (round trip) is 0.21 uH (micro Henries).
8. The capacitance per foot between the two conductors is 30 pF per foot
9. Our power amplifier produces 35 Watts per channel
So, the total cable resistance of the loudspeaker cables in our system is 10 feet x 0.008 Ohms = 0.08 Ohms total per channel.
The RMS current in our speaker cable will therefore be 2.08 Amperes. The power loss in the speaker cable will be 0.1667 Watts, reducing the usable system power down to 34.83 Watts from 35 Watts at the power amplifier.
The degradation of the amplifier dampening factor will become 24.24 (as opposed to 25 per the rating of our power amplifier)
The signal loss at 1000 Hz due to inductance will be 0.027 Volts or 0.012 dB. (The resistance term substantially dominates the Impedance of this system over the reactive components)
The -3dB corner frequency due to inductance will be 19 kHz.
The -3dB corner frequency due to loading capacitance on the amplifier will be 66 MHz.
The resonant frequency of the cable system will be 634 kHz.
Conclusion: The use of common 16 AWG zip cord to connect up your loudspeakers to your power amplifier will have almost no impact on the audio signal quality presented to the listener.
A Note of Warning: The use of extremely low inductance cable in conjunction with a very wide-bandwidth audio power amplifier can cause sustained oscillations because of the very high capacitance associated with such cable (sometimes consisting of two flat ribbons of copper with a dielectric in between). If the pole produced by the capacitance of such a cable competes with the dominant compensation pole of the power amplifier, it could create a 2nd order rolloff at the amplifier's gain crossover frequency which is the boundary condition for producing sustained oscillations. This situation can damage the power amplifier and/or the high-frequency drivers in your speaker system.
Craig
1. The loudspeaker is rated at 8 Ohms and is mostly resistive (not reactive).
2. The dominant impedance component for the speaker drivers is 6 Ohm resistive @ 1000 Hz
3. The Audio Power Amplifier in our system has a rated dampening factor of 25 into an 8 Ohm driver, meaning that its source resistance is around 0.25 Ohms, non-reactive at 1 kHz
4. The distance between the Power Amplifier(s) and the loudspeakers is 10 feet.
5. The cable connecting the Power Amplifier to the loudspeakers is 16 AWG zip cord (commonly found at any hardware store).
6. The resistance per foot is 0.004 Ohms per foot (each direction) making the aggregate resistance per foot 0.008 Ohms per foot.
7. The inductance per foot (round trip) is 0.21 uH (micro Henries).
8. The capacitance per foot between the two conductors is 30 pF per foot
9. Our power amplifier produces 35 Watts per channel
So, the total cable resistance of the loudspeaker cables in our system is 10 feet x 0.008 Ohms = 0.08 Ohms total per channel.
The RMS current in our speaker cable will therefore be 2.08 Amperes. The power loss in the speaker cable will be 0.1667 Watts, reducing the usable system power down to 34.83 Watts from 35 Watts at the power amplifier.
The degradation of the amplifier dampening factor will become 24.24 (as opposed to 25 per the rating of our power amplifier)
The signal loss at 1000 Hz due to inductance will be 0.027 Volts or 0.012 dB. (The resistance term substantially dominates the Impedance of this system over the reactive components)
The -3dB corner frequency due to inductance will be 19 kHz.
The -3dB corner frequency due to loading capacitance on the amplifier will be 66 MHz.
The resonant frequency of the cable system will be 634 kHz.
Conclusion: The use of common 16 AWG zip cord to connect up your loudspeakers to your power amplifier will have almost no impact on the audio signal quality presented to the listener.
A Note of Warning: The use of extremely low inductance cable in conjunction with a very wide-bandwidth audio power amplifier can cause sustained oscillations because of the very high capacitance associated with such cable (sometimes consisting of two flat ribbons of copper with a dielectric in between). If the pole produced by the capacitance of such a cable competes with the dominant compensation pole of the power amplifier, it could create a 2nd order rolloff at the amplifier's gain crossover frequency which is the boundary condition for producing sustained oscillations. This situation can damage the power amplifier and/or the high-frequency drivers in your speaker system.
Craig