Audioquest SLiP-DB 16/2 gray

A speaker cable that ends up inside a partition wall, above a suspended ceiling or in a trench at the bottom of the garden is not something you replace every other day. This one combines two 1.31 mm² long-grain copper conductors, semi-solid strand construction and a grey jacket approved for both in-wall installation and direct burial. Sold by the metre, it can be cut to the exact length of each connection between the amplifier and the speakers.

Long-grain copper in strands that stay in place

Viewed under a microscope, a copper conductor consists of adjacent crystals, or grains, and each boundary between two grains represents a small discontinuity along the signal path. AudioQuest’s LGC (Long-Grain Copper) has longer grains than the OFHC (oxygen-free high-conductivity) copper used in ordinary cables, meaning fewer boundaries per metre, along with fewer oxides and impurities in the metal.

The way this copper is assembled matters just as much as its purity. In a conventional stranded cable, dozens of fine strands twist around and change position along the cable, and each interacts electrically and magnetically with neighbours that are never the same from one point to the next. Semi-Solid Concentric construction aims to eliminate these changing interactions: the strands, fewer in number and packed around a centre, maintain a fixed position relative to one another along the entire length. The resulting conductor sits between flexible stranded wire and solid wire. It holds the shape you give it inside a partition wall or along a skirting board, but bends less readily around tight corners and requires careful stripping.

A tight twist to keep inductance in check

A speaker cable forms a loop: current flows from the amplifier through one conductor and returns through the other. The farther apart these two conductors are, the larger the loop area and the higher the cable’s inductance, which progressively attenuates the upper frequencies as the length increases. The two conductors in the SLiP-DB 16/2 are twisted in a spiral (Spiral Geometry), an arrangement that minimises this area. Over two or three metres behind a piece of furniture, the difference remains modest; over the ten- or fifteen-metre runs of an in-wall installation, geometry has a greater influence on the final balance.

The conductors are also direction-controlled (Direction-Controlled), a principle AudioQuest applies to all its cables to limit radio-frequency noise. With cable sold by the metre, this means installing every length in the same direction.

A grey jacket for partition walls and direct burial

The EasySLiP jacket is deliberately minimalist: a thin, smooth PVC covering that slides without snagging through a conduit, behind plasterboard or above a suspended ceiling. Its grey colour with red stripes makes it instantly distinguishable from electrical cables when several systems share the same partition wall.

It carries CL3 and FT4 approvals. The first, established under North American UL standards, classifies the cable among low-voltage signal cables permitted inside walls (up to 300 V); the second corresponds to a Canadian flame propagation test on a vertical bundle of cables. The DB (Direct Burial) suffix indicates that the jacket can withstand direct burial in the ground, without conduit, to feed outdoor speakers at the bottom of a garden or around a patio. Running the cable through TPC conduit remains good practice: it protects it from a spade strike and allows it to be replaced without reopening the trench.

How far to run a 1.31 mm² cable

Each conductor measures 1.31 mm², equivalent to 16 AWG in the American wire gauge system. In copper, a connection has approximately 0.026 ohm of resistance per metre, including both the outgoing and return paths. A common rule of thumb is to keep cable resistance below 5% of the speaker’s impedance, a threshold beyond which the level drops noticeably and the amplifier has less control over the woofer’s movement. For 8-ohm speakers, this allows a run of around 15 metres; for 4-ohm speakers, closer to 7 to 8 metres.

These distances cover most in-ceiling speakers, zones in a multiroom system, rear channels in a home cinema and outdoor speakers close to the house. Beyond that, or with low-impedance speakers far from the amplifier, the 2.08 mm² (14 AWG) cross-section in the same SLiP-DB family reduces resistance by a good third.

A mark every 30 cm for precise cutting

The jacket carries metric markings with sequential numbering every 30 cm, up to 150 m. Simply noting the number at the start and finish tells you the length installed without unrolling a tape measure, making it easier to prepare several runs to different rooms.

When ordering, simply add up each run, then allow 30 to 50 cm of spare cable at each end to work comfortably inside a recessed back box or behind an amplifier. The bare ends connect to screw or spring terminals, or can be fitted with banana plugs or spade connectors. With semi-solid strands, a correctly sized wire stripper prevents nicking the copper.

Technical Specifications

Composition

• Metal: 100% semi-rigid concentric copper with low gas content (LGC)
• Section: 2 × 1.31 mm²

Sheath

• Type: Gray PVC
• Certification: CL3, FT4

Marking

• Type: Metric
• Sequential numbering every 30 cm (1-150 m)

Packaging

• Sold by the meter