How much signal loss is acceptable?

For analogue audio, losses under 1 dB are generally inaudible. Losses of 1-3 dB may be noticeable in critical listening. Above 3 dB, signal degradation becomes significant. High-frequency losses tend to be more noticeable than broadband attenuation.

Why do high frequencies suffer more loss?

Cable capacitance creates a low-pass filter with the source impedance. Higher frequencies see more attenuation because capacitive reactance decreases with frequency. This effect is most pronounced with high-impedance sources like passive guitar pickups.

Does cable capacitance matter for digital audio?

For analogue connections, capacitance affects tone. For digital connections (AES3, S/PDIF), what matters is matching the characteristic impedance (110Ω for AES3, 75Ω for S/PDIF). Impedance mismatches cause reflections and data errors.

Are the per-metre dB loss figures from a datasheet?

No — the 1 kHz and 10 kHz loss-per-metre figures here are indicative estimates to give a rough feel for relative cable performance, not values taken from a specific manufacturer datasheet. For real analogue runs, 1 kHz attenuation is governed by conductor resistance and is negligible (hundredths of a dB) over normal lengths. The meaningful result for analogue cable is the high-frequency -3 dB rolloff, which is computed directly from your source impedance and the total cable capacitance. For exact loss, use the cable resistance and capacitance from the manufacturer datasheet (e.g. Belden, Mogami, Canare).

How is signal loss in speaker cable different?

Speaker-cable loss is almost entirely resistive and frequency-independent across the audio band. A useful rule of thumb is that about 1 Ω of total cable resistance costs roughly 1 dB into an 8 Ω load: loss (dB) = 20·log10(Zload / (Zload + Rcable)). The thicker the conductor (lower AWG) and the shorter the run, the lower the loss — wire gauge and length matter, not a fixed dB per metre.

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How We Calculate This

For analogue audio the dominant audible effect of a cable run is the high-frequency rolloff caused by cable capacitance forming a low-pass filter with the source impedance:

-3 dB frequency = 1 / (2π × R × C)

where R is the source impedance and C is the total cable capacitance (length × capacitance per metre). A passive guitar pickup driving a high source impedance (~10 kΩ) through 10 m of 100 pF/m cable (1000 pF total) has a -3 dB point around 16 kHz — the higher the source impedance and the longer the cable, the lower this corner frequency drops into the audible band.

The broadband loss-per-metre figures shown are indicative estimates, not datasheet values. In reality, broadband (1 kHz) attenuation on mic, instrument and line runs is set by conductor resistance and is negligible — a few hundredths of a dB — over normal lengths. Speaker-cable loss is purely resistive: roughly 1 Ω of cable resistance costs about 1 dB into an 8 Ω load, and it is the same at 1 kHz and 10 kHz because skin effect is negligible at audio frequencies.

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Last updated: February 2026

All calculations are estimates based on standard formulas. Always verify results for critical applications.

Signal Loss Calculator — Audio Cable Attenuation