There's no shortage of speaker wire brands, design and engineering philosophy. Solid core and stranded speaker wires comprise the two predominant cabling types, each with their own benefits and drawbacks. Solid core wires, also known as Litz wires, are not as common but have very specific electrical advantages. These properties cause many audio enthusiasts to choose solid wire over more common and typically less expensive stranded cabling alternatives.
The key to getting a speaker moving in response to the signal from an amplifier is to impede that signal as little as possible. In electrical terms, that means low resistance. Solid core speaker wire, like the thick AC power lines carrying high voltage throughout your house, offers very low resistance compared to stranded wire. Stranded wire has microscopic spaces between individual strands, resulting in slightly more power loss over the same gauge solid wire.
The copper in a solid-core speaker cable is linear, comprised of single heated and stretched sections of copper. Stranded wires rely on a precise process of tightly twisting individual strands to simulate the effects of a solid wire. All else being equal, solid core copper wires carry more electrical current farther than their stranded cousins. This means that you can use a "smaller" gauge solid wire and achieve the same sound performance as a thicker stranded equivalent. This may prove useful in multi-room audio systems, where multiple wires are pulled through studs and placed in tight spaces.
Different wires within a solid-core cable configuration each have their own magnetic fields, with higher frequencies such as cymbal crashes traveling to the outside of a speaker cable. This "skin effect" is mitigated by weaving individually-insulated wires in a helix pattern, keeping these fields evenly distributed. This helps decrease inductance, which is the tendency of speaker wires to resist changes in electrical current. In so doing, properly-built solid core speaker wires transfer power from an amplifier to a speaker more efficiently than comparable stranded wires.
Solid core wire is generally easier to manufacture than stranded alternatives. Solid core copper wires simply need to be softened and stretched, known as the annealing process. Barring manufacturer-specific features that increase the retail price, solid core wire is cheaper to manufacture. Stranded wires tend to have comparatively higher manufacturing costs, derived from the need for more insulation to cover the finished product and the processes required in carefully twisting the individual strands.
Solid Core Wire Drawbacks
For all the increase in performance typically realized over stranded alternatives, there are times where stranded cabling may prove the wiser choice. Solid core wires are stiffer than stranded wires, potentially making them harder to bundle and manipulate due to their lack of flexibility. Additionally, flexing solid metal strands eventually weakens and breaks the wire, like a paper clip repeatedly bent back and forth. For these reasons, stranded speaker wires are more commonly found in environments where the cables are constantly flexing and moving, such as car stereo applications. Solid core wires require a wire nut for splicing, since conventional crimp-style connectors may break the wire or have an uneven internal connection. This makes the splice potentially less cosmetically appealing if it must take place along a visible section of the cable, and may be more difficult since each inner conductor is usually individually-insulated.
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