Speaker Wire Guide: How To Choose The Right Gauge
Speaker wires are intended to transfer the signal and energy from the audio amplifiers to the speakers, hence their name. Speaker wires differ in material, construction, thickness, and a few other features which can be rather different.
Speaker wire consists of two or sometimes more identical electrical conductors with different markings in order to identify themselves more easily. Correctly sized speaker wire has very little effect on the audio signal quality despite the claims by some wire manufacturers which often use technical terms like "skin effect", "impedance", "resonance", etc. in order to confuse and impress end users.
Published: June 22, 2022.
On This Page:
- Speaker Wire Features, Materials, and Specifications
- Speaker Wire Gauge Charts
- Speaker Wire Frequently Asked Questions (FAQ)
- Few Final Words
Speaker Wire Features, Materials, and Specifications
Speaker wire is described with its electric impedance (Z) which consists of resistance, capacitance, and inductance. An ideal speaker wire has no resistance, no capacitance, and no inductance - however, there is no ideal speaker wire.
Speaker Wire Resistance
Regardless of the wire material and thickness, the speaker wire will always have some resistance - speaker wires made using room temperature superconductors are still far future.
But, as long as the speaker wire resistance is kept to less than or equal to 5% of the speaker's impedance, the conductor will be more than good enough for home use.
If You want better quality than that, just go for a slightly thicker wire.
Speaker Wire Capacitance
Capacitance occurs between speaker wire conductors and it can't be avoided.
However, signal loss (attenuation) due to the speaker wire capacitance is negligible since the audio signal features frequencies up to 20 kHz, which is a very low frequency to cause any significant signal loss or degradation.
Note: typical capacitance of a speaker wire ranges from 5 to 25 pF (pico Farad) per foot, although some high-end speaker wires have a somewhat larger capacitance in order to decrease the wire inductance - generally, as long as the speaker wire is 50 feet (15 m; 100 feet (30 m) of conductors) or shorter, the speaker wire will have less than 1% of capacitive loss in the frequency range below 20 kHz.
Speaker Wire Inductance
Just like capacitance, inductance occurs between speaker wire conductors and it can't be avoided.
In order to keep the signal attenuation below 1% in the audio range (frequency up to 20 kHz), total speaker wire inductance must be kept below ~2 μH (micro Henry).
The typical inductance of the speaker wires ranges from 0.05 to 0.2 μH per foot, with premium speaker wires featuring inductance in the 0.02 - 0.05 μH/foot range.
In order to keep the signal loss below 1% due to the inductance, one should use up to ~5 feet (10 feet of conductors) of "ordinary" speaker wires or up to 25 feet (50 feet of conductors) of premium speaker wires.
Skin effect is caused by the cable self-inductance - as the frequency of the signal is increased, the signal tends to travel more on the surface of the cable and less through its core.
Due to the skin effect, the cable's resistance is increased with the frequency of the signal.
Also, the skin effect affects stranded conductors too. So-called Litz Wires feature individually insulated strands often twisted in pairs with different twist rates - even such wires won't show any improvements for audio signals (up to 20 kHz).
In order to decrease the skin effect, some manufacturers even offer copper wires where copper strands are plated with silver.
However, while the skin effect may cause issues for radio frequencies, for audio frequencies, its effect is negligible.
Speaker Wire Material
Most speaker wires are made out of copper which has low resistance and moderate price. Copper over time may oxidize, but copper oxides are still conductive.
Oxygen-Free Copper (OFC) wires are sold in several grades, but the actual difference between them and "ordinary" copper wires for audio applications (signal frequency up to 20 kHz) is practically negligible.
Copper Clad Aluminum (CCA) wires feature an aluminum core and outer copper cladding. CCA wires are lighter and cheaper than copper wires but have somewhat higher resistance.
Aluminum wires are lighter than copper wires but feature somewhat higher resistance. Also, aluminum oxide which is created on the aluminum surface is not conducive.
Silver is an excellent conductor, but it costs more than copper and is rarely used.
Gold features higher resistance than copper, but it doesn't oxidize and is often used for plating wire terminals and connectors.
For short - for your audio system, go for a good copper wire, and don't complicate things :)
Speaker Wire Gauge Charts
The most common speaker wire material for car or home audio systems is copper or CCA (Copper Clad Aluminum).
A general rule of thumb is that the resistance of a speaker wire should not exceed 5% of the rated speaker impedance.
Copper Speaker Wire Chart
The following chart displays the maximum recommended copper speaker wire length depending on the speaker impedance - chart is given for the most common speaker impedances of 2Ω, 4Ω, 6Ω, 8Ω, and 16Ω.
|Speaker Copper Wire Max. Length|
|8||3.2636||0.1285||8.3656||0.0130||72 ft (~22 m)||144 ft (~44 m)||216 ft (~66 m)||288 ft (~88 m)||577 ft (~176 m)|
|10||2.5882||0.1019||5.2612||0.0082||50 ft (~15 m)||100 ft (~30 m)||150 ft (~46 m)||200 ft (~61 m)||400 ft (~122 m)|
|12||2.0525||0.0808||3.3088||0.0051||30 ft (~9.1 m)||60 ft (~18 m)||90 ft (~27 m)||120 ft (~36 m)||240 ft (~73 m)|
|14||1.6277||0.0641||2.0809||0.0032||20 ft (~6.1 m)||40 ft (~12 m)||60 ft (~18 m)||80 ft (~24 m)||160 ft (~49 m)|
|16||1.2908||0.0508||1.3087||0.0020||12 ft (~3.6 m)||24 ft (~7.3 m)||36 ft (~11 m)||48 ft (~15 m)||96 ft (~29 m)|
|18||1.0237||0.0403||0.8230||0.0013||8 ft (~2.4 m)||16 ft (~4.9 m)||24 ft (~7.3 m)||32 ft (~9.7 m)||64 ft (~19 m)|
|20||0.8118||0.0320||0.5176||0.0008||5 ft (~1.5 m)||10 ft (~3 m)||15 ft (~4.5 m)||20 ft (~6 m)||40 ft (~12 m)|
|22||0.6438||0.0253||0.3255||0.0005||3 ft (~0.9 m)||6 ft (~1.8 m)||9 ft (~2.7 m)||12 ft (~3.6 m)||24 ft (~7.3 m)|
|24||0.5106||0.0201||0.2047||0.0003||2 ft (~0.6 m)||4 ft (~1.2 m)||6 ft (~1.8 m)||8 ft (~2.4 m)||16 ft (~4.9 m)|
Copper Clad Aluminum (CCA) Speaker Wire Chart
Although the weight savings of using CCA instead of copper wire for car and home audio systems are very small, some users prefer CCA wires over copper wires.
The following chart displays the maximum recommended CCA speaker wire length depending on the speaker impedance:
|Speaker CCA Wire Max. Length
|8||3.2636||0.1285||8.3656||0.0130||53 ft (~16 m)||105 ft (~32 m)||158 ft (~48 m)||211 ft (~64 m)||421 ft (~128 m)|
|10||2.5882||0.1019||5.2612||0.0082||35 ft (~10 m)||70 ft (~21 m)||105 ft (~32 m)||140 ft (~42 m)||279 ft (~85 m)|
|12||2.0525||0.0808||3.3088||0.0051||23 ft (~7 m)||45 ft (~13 m)||68 ft (~20 m)||90 ft (~27 m)||181 ft (~55 m)|
|14||1.6277||0.0641||2.0809||0.0032||15 ft (~4.5 m)||30 ft (~9.1 m)||44 ft (~13 m)||59 ft (~18 m)||118 ft (~36 m)|
|16||1.2908||0.0508||1.3087||0.0020||9 ft (~2.7 m)||17 ft (~5.2 m)||26 ft (~7.8 m)||34 ft (~10 m)||69 ft (~21 m)|
|18||1.0237||0.0403||0.8230||0.0013||7 ft (~2.1 m)||13 ft (~4.1 m)||20 ft (~6.1 m)||27 ft (~8.2 m)||54 ft (~16 m)|
|20||0.8118||0.0320||0.5176||0.0008||4 ft (~1.2 m)||9 ft (~2.7 m)||13 ft (~3.9 m)||17 ft (~5.2 m)||34 ft (~10 m)|
|22||0.6438||0.0253||0.3255||0.0005||3 ft (~0.9 m)||5 ft (~1.5 m)||8 ft (~2.4 m)||11 ft (~3.3 m)||21 ft (~6.4 m)|
|24||0.5106||0.0201||0.2047||0.0003||1 ft (~0.3 m)||3ft (~0.9 m)||4 ft (~1.2 m)||6 ft (~1.8 m)||11 ft (~3.3 m)|
As one can see, for the same speaker resistance and wire length, CCA wires must be thicker than copper wires. But, if the weight of the cable is an issue, note that CCA wires feature lower resistance than copper wires for the same weight.
Also, CCA wires are (somewhat) cheaper, they produce excellent sound (just like good copper wires) and are very popular among audio enthusiasts.
Speaker Wire Frequently Asked Questions (FAQ)
Here are some of the most common Frequently Asked Questions (FAQ) about speaker wires and wiring in general:
Which is positive and negative on speaker wire?
Actually, there is no standard regarding the color of speaker wires - the most important thing is to be consistent.
- if one of the wires is black, it is a positive wire,
- if You have brown and blue wires, brown is positive and blue is negative/ground,
- if one of the wires is green/yellow, it is negative/ground wire, etc.
What gauge is best for speaker wire?
There is no "the best" speaker wire gauge - check the documentation of both your audio system and speakers (impedance) and find the best speaker wire gauge for your audio system. Or use wire gauge as listed in our charts according to the speaker impedance that You have.
What kind of speaker wire is best?
The best speaker wire is one with no resistance, no capacitance, and no inductance - and such wire doesn't exist.
Copper audio wires are excellent, but they cost more than CCA wires but are cheaper than pure silver (99.999% silver) wires that often come with additional shielding.
CCA wires are very popular audio wires - they are relatively cheap and they reproduce sound well.
Is speaker wire just regular wire? Can the regular copper wire be used as speaker wire?
Yes, regular copper wire can be used as a speaker wire - it will allow the user to listen to the audio on the speakers.
However, speaker wires are not expensive, so if You are building an audio system or just connecting speakers to the amplifier for general use, do yourself a favor and get a good speaker wire.
How many watts can 18 gauge wire handle?
Actual wire/audio system wattage depends on many variables, not just wire thickness - voltage, speaker impedance, etc.
For most low(er) power car and home audio systems (without subwoofers), 18 gauge wire is a good wire for 50W @4Ω or for 100W @8Ω.
However, 16 gauge wire is just a little bit thicker and if unsure, instead of 18 gauge wire, go for 16 gauge wire.
What is the difference between 14 gauge and 16 gauge speaker wire?
14 and 16-gauge wires differ in thickness and cross-section area - 14-gauge wire is thicker and thus is able to handle more Amps/Watts than 16-gauge wire.
Must an audio system with multiple speakers have speaker wires of the same length?
Generally, no, an audio system with multiple speakers doesn't have to feature speaker wires of the same length.
However, it is highly recommended that the wires are of the same or almost the same length - wires of different lengths can cause sound strength imbalances, but that would require a really large difference in length.
But, just in case, the wires should be of almost the same length.
Few Final Words
For home, car, and similar audio systems with wire lengths up to 50 feet (15m), go for good speaker copper/CCA wires and don't look any further. If the audio wires must be longer, consider premium speaker wires with lower inductance.
Note: general speaker copper wires can produce excellent sound up to 200-300 feet, but there are always people who insist on even better sound quality. And why not? After all, if somebody spends thousands of dollars/euros on vacuum tube amplifiers and high-end speakers, there is really no point in decreasing the performance of such audio systems by using cheap copper/CCA wires...
Having thicker wires can decrease the resistance and up to the point, decrease the signal loss, however, too thick speaker wires simply don't justify their installation in terms of signal improvement. And they cost more, of course.
And speaking about the costs