Mr_m, yes, inductance and most other cable parameters are proportional to length, including resistance, capacitance, the resistance rise at high frequencies caused by skin effect, the effects of dielectric absorption, and propagation delay.
In the case of analog cables, inductance is most likely to be audibly significant in speaker cable applications, especially if the impedance of the speaker is low at high frequencies (as it generally is in the case of electrostatic speakers), and/or if the cable length is long, and/or if the particular cable has relatively high inductance per unit length. The impedance presented by an inductance is proportional to frequency, and therefore in the upper treble region may become an audibly significant fraction of the impedance of the speaker in those situations.
Inductance (as well as resistance) will usually be unimportant in the case of line-level analog interconnects, since the corresponding impedances will be vastly smaller than the input impedance of the component receiving the signal. In that application capacitance will often be important, particularly if the output impedance of the component providing the signal is high.
In the case of digital cables, inductance is one of the key determinants of what is called "characteristic impedance," which for coaxial S/PDIF is nominally the 75 ohm figure you are probably used to seeing mentioned, and for AES/EBU is nominally the 110 ohm figure you are probably used to seeing mentioned. The characteristic impedance of a cable is NOT proportional to length. However at the RF frequencies which comprise digital audio signals the less than perfect impedance match that will inevitably exist to some degree between the cable’s characteristic impedance and the nominally 75 or 110 ohm impedances of the connected components will result in some fraction of the signal energy reflecting and re-reflecting back and forth along the cable. The arrival of those reflections and re-reflections at the DAC will result in some degree of distortion of the signal waveform as received by the DAC, which may or may not ultimately affect timing jitter at the point of D/A conversion, depending on the arrival times and also on the design of the particular DAC. And those arrival times will be dependent on the length of the cable as well as on the propagation velocity of the particular cable. That is explained well in the paper by Steve N. of Empirical Audio that was linked to earlier.
Regards,
-- Al
In the case of analog cables, inductance is most likely to be audibly significant in speaker cable applications, especially if the impedance of the speaker is low at high frequencies (as it generally is in the case of electrostatic speakers), and/or if the cable length is long, and/or if the particular cable has relatively high inductance per unit length. The impedance presented by an inductance is proportional to frequency, and therefore in the upper treble region may become an audibly significant fraction of the impedance of the speaker in those situations.
Inductance (as well as resistance) will usually be unimportant in the case of line-level analog interconnects, since the corresponding impedances will be vastly smaller than the input impedance of the component receiving the signal. In that application capacitance will often be important, particularly if the output impedance of the component providing the signal is high.
In the case of digital cables, inductance is one of the key determinants of what is called "characteristic impedance," which for coaxial S/PDIF is nominally the 75 ohm figure you are probably used to seeing mentioned, and for AES/EBU is nominally the 110 ohm figure you are probably used to seeing mentioned. The characteristic impedance of a cable is NOT proportional to length. However at the RF frequencies which comprise digital audio signals the less than perfect impedance match that will inevitably exist to some degree between the cable’s characteristic impedance and the nominally 75 or 110 ohm impedances of the connected components will result in some fraction of the signal energy reflecting and re-reflecting back and forth along the cable. The arrival of those reflections and re-reflections at the DAC will result in some degree of distortion of the signal waveform as received by the DAC, which may or may not ultimately affect timing jitter at the point of D/A conversion, depending on the arrival times and also on the design of the particular DAC. And those arrival times will be dependent on the length of the cable as well as on the propagation velocity of the particular cable. That is explained well in the paper by Steve N. of Empirical Audio that was linked to earlier.
Regards,
-- Al