UNDERSTANDING WIRE SIZE AND
WIRE GAUGE FOR AUDIO CABLES
WIRE GAUGE FOR AUDIO CABLES
by Mark King for proworkshop.com
In the USA the wire inside audio cables is measured against a standard called "American Wire Gauge". A wire gauge is a handheld tool capable of measuring the diameter of a conductor.
The American Wire gauge (AWG) is the standard used in the USA for measuring the diameter of a solid-core electrical conductor.
In the USA we simply refer to wire size by a number and the word "gauge". A large speaker wire would be made from 12-gauge, a line-level balanced-line might be constructed of 22-gauge or even smaller 24-gauge conductors.
Solid core wire is the standard for building power wiring but for audio, stranded-wire is what is used most often because it is so much more flexible and durable in applications where the wire is subject to any physical movement.
Small diameter solid-core wire is very easy to break when bent at hard angles, stranded-wire is typically much more flexible.
AWG gauges are also used to describe stranded wire. In this case, it describes a wire which is equal in cross-sectional area to the total of all the cross-sectional areas of the individual strands; the gaps between strands are not counted. When made with circular strands, these gaps occupy about 10% of the wire area, thus requiring a wire about 5% thicker than equivalent solid wire.
|EXAMPLES OF SOLID CORE (top) AND STRANDED WIRE (bottom)|
Stranded wires are specified with three numbers, the overall AWG size, the number of strands, and the AWG size of a strand. The number of strands and the AWG of a strand are separated by a slash. For example, a 22 AWG 7/30 stranded wire is a 22 AWG wire made from seven strands of 30 AWG wire.
FUNNY INVERSE NUMBERING SCHEME
The most important thing to understand about AWG (American Wire Gauge) is that as the numbers get bigger the conductor diameter gets smaller!
Notice that a 14-gauge conductor is a whole lot smaller than a 2-gauge conductor.
32-gauge is really small while 12-gauge is considered large for audio applications.
ADVANTAGE OF LARGER CONDUCTORS
Wire has a characteristic called "resistance" which is measured in "ohms per foot". The electrical resistance of an electrical conductor is a measure of the difficulty to pass an electric current through that conductor. Less ohms per foot is better than greater ohms per foot.
For the best audio performance you want the least resistance per foot within reasonable cost.
RECOMMENDED WIRE SIZE BY APPLICATION
For speakers 10 gauge, 12 gauge, 14 gauge and 16 gauge are common wire sizes.
10 gauge has less ohms per foot than 16 gauge.
|Massive Stranded-wire Cables Used for High-Current applications, you don't need this for speaker cables LOL!|
For shorter wire runs of less than 50-feet, 24 gauge can work acceptably. For wire lengths greater than 50-feet a larger wire conductor size such as 22 gauge can deliver more reliable and better performance.
For musical instrument cables (aka guitar cords), 20 gauge is large and 24 gauge is on the small side for making these cables. Guitar cords are almost always constructed using stranded wire which keeps them flexible.
Some guitar cord companies produce cables using 20-gauge, the only disadvantage of this is higher cost and a heavier cable. Up to a certain point larger wire delivers superior performance. Larger than 20-gauge for musical instrument level cables provides diminishing returns to the user.
Some specialty cables use solid silver conductors but these are rare and considerably more expensive.
THE RIGHT LENGTH FOR CABLES
For amplifier-to-speaker connections you always want the largest wire (within reason) that you can accommodate.
Another factor is the length of the cables, longer cables = larger wire gauge for best performance. The best course of action is to keep the distance between the amplifier output and the input to the speaker as short as possible. This has given rise to the popularity of powered-speakers or systems which combine the amplifier and speaker into a single integrated enclosure.
The ability of an amplifier to precisely control the motion of a speaker cone can also be affected by the size of wire used. For the highest damping factor Crown amplifiers recommended 1-0 or even 4-0 size cable for their premium studio monitor amplifier installations. This was impractical for most because there are no audio connectors that can terminate this size of wire.
Guitar cords = shorter is best
- A high quality 10 foot guitar cord is best for electric guitar studio work
- Longer than 20 feet usually means high frequency rolloff with passive instruments
- 30 feet is about the maximum length for a guitar cord before significant sonic degradation occurs with passive instruments like Les Paul and Stratocaster guitars
- Keyboards, synthesizers and active instruments can work with up to 100 foot instrument cables without significant audio degradation
Microphone and Line-Level, Low-impedance cables = 24 gauge or larger, 22 gauge or larger for lengths over 50 feet
Speaker cables up to 50 feet
- 18 gauge may be used for low power applications of 100 watts or less with minimum loss
- 16 gauge may be used for low power applications of 400 watts or less with minimum loss
- 14 gauge will deliver better performance
- 12 gauge may deliver better performance but diminishing returns start to come into play
Speaker cables over 50 feet
- 12 gauge is recommended, for cable runs over 100 feet larger wire may be needed depending on how much amplifier power is being delivered
LIES, LIES AND MORE LIES
It is common for many cable companies to exaggerate the actual size of the wire they're using in the construction of the cables they produce. Imported cables from the far east are almost all guilty of this.
Don't be surprised if that bargain 12 gauge speaker cable you just bought online actually uses stranded conductors which are more like 16 gauge. It is up to you to know the difference and reject the inferior quality products or else your audio quality may suffer substantially.
I have opened up guitar cords and found 26 gauge center conductors, I usually throw these away since in my experience these offer the worst audio quality.
One reason for all the discrepancy between wire size is the way wire diameter is measured, in the USA we use the American Wire Gauge, other standards are used outside the USA. Poor language translation is often blamed for the discrepancy between the wire size advertised and what is actually delivered. Again, it is up to you to know what you need and recognize inferior products which may be marketed falsely.
The most obvious reason for overstating wire size is cost, copper is expensive and larger wire means more copper used to produce it. Bigger wire costs more to make so smaller wire is slipped in as a replacement to save cost. While technically this is false advertising and illegal there is nobody to watch over this and regulate it so it is up to you to recognize and accept or reject on a case by case basis.
Understanding the confusing inverse numbering scheme of wire gauge is one of the hardest things for beginning sound engineers to grasp fully.
For a more complete and in-depth look at American Wire Gauge here is a link to a detailed explanation on Wikipedia.
Good luck and good music to all!