What Makes a Microphone Cable “Balanced”
A balanced audio connection sends the same signal on two conductors, with the second conductor carrying an inverted copy. The receiving device subtracts the two, which cancels noise picked up identically on both wires and doubles the signal. This is why professional microphone and line-level runs use balanced wiring with XLR connectors.
The cable itself supports this: a two-core construction with a shield. One core carries the positive (hot) signal, the other the negative (cold), and the shield — connected to pin 1 of the XLR — carries the ground and drains interference.
2-Core Shielded or 3-Conductor? Two Names for the Same Cable
Balanced microphone cable is sold under two different naming conventions, and both are correct:
- By core count — “2 core shielded”, counting the two insulated signal cores and treating the shield separately.
- By total conductor count — “3 conductor” (or “3 core”), counting the two signal cores plus the shield/drain as the third conductor. This is the convention used by major cable makers such as Belden, whose microphone cable range is listed under “Three Conductor”.
So a 2-core shielded microphone cable and a 3-conductor microphone cable describe the same construction. When ordering, quote both terms or state the construction explicitly to avoid ambiguity.
How Shielding Works
Shielding wraps the signal cores in a conductive layer that blocks or drains electromagnetic interference. Two common approaches are:
- Foil shielding: a thin aluminium layer wrapped around the cores. Good high-frequency coverage, lightweight, cost-effective.
- Copper braid shielding: a woven mesh of copper strands. Mechanically strong, handles flexing and repeated coiling well, and provides a solid ground path.
The LBS microphone cable range combines both: an AL-Foil Mylar layer plus a tinned-copper braid, in a double-shielded construction with over 95% coverage, to protect balanced microphone and line-level signals.
Speaker cable is the other case. A speaker line is high-level and low-impedance, so a twisted pair usually does the job without a shield; the reasoning, and the conditions where a shielded speaker construction is required, is in do speaker cables need shielding?
Conductor Size and Cable Capacitance
The conductor size (in mm²) affects how much signal loss occurs over distance. For standard microphone runs, LBS offers two sizes:
| Bulk cable model | Conductor | Conductor resistance | O.D. | Routing category |
|---|---|---|---|---|
| LBSMIC-1-2X0.3 | 2 × 0.3 mm² | ≤55 Ω/km | 6.0 – 6.5 mm | Standard routing |
| LBSMIC-1-2X0.5 | 2 × 0.5 mm² | ≤40 Ω/km | 6.8 – 7.2 mm | Long-distance routing |
Both sizes use PE insulation, a tinned-copper conductor and a core-to-core capacitance of ≤120 pF/m. Lower capacitance matters on long runs, which is why the larger 0.5 mm² size is specified where cable length is significant.
Bulk Cable or Finished XLR Cable?
The same two constructions are available in two forms:
- Bulk cable (LBSMIC-1 series) — bare cable on 100 m rolls or 305 m drums, for installers terminating their own XLR or TRS connectors.
- Finished patch cable (LBSMIC-2 series) — factory-assembled with 3-pin XLR male / female connectors, zinc-alloy housing and nickel-plated contacts, for rental stock and ready-to-use patching.
Jacket and Temperature Rating
Microphone cable for stage work needs a jacket that survives repeated coiling, foot traffic and road cases. The LBS microphone range uses a flexible EPVC jacket with an operating range of −20 °C to +70 °C. The characteristic impedance is 50–70 Ω for balanced audio, and the rated voltage is 30 V.
One more thing belongs in a project specification when this cable is not a single lead but one channel of a run: how many balanced channels travel together, and what each one is numbered. A balanced channel is one way of a multichannel snake, and the ways are counted with the returns and spares before a size is ordered — see how many ways a stage-to-mixer multicore needs.
What to Specify for Your Project
When ordering microphone cable for an OEM or installed project, confirm:
- Conductor size based on run length — 2 × 0.3 mm² for standard routing, 2 × 0.5 mm² for longer runs.
- Bulk or finished — bare cable for your own termination, or factory-fitted 3-pin XLR.
- Jacket colour and printing — brand name, model and specification can be printed on the jacket for OEM orders.
- Packaging — 100 m rolls, 305 m drums or custom lengths.
LBS supports OEM/ODM orders on the microphone cable range: custom jacket colours, brand/model printing, custom lengths and packaging. Contact LBS for OEM microphone cable for project details.
FAQ
Is a 2-core shielded cable the same as a 3-conductor cable?
Yes. The two names describe the same construction: two insulated signal cores plus a shield (with drain) that acts as the third conductor. Belden and other major manufacturers list this construction as “Three Conductor”.
What is the difference between LBSMIC-1 and LBSMIC-2?
LBSMIC-1 is bulk cable for installers to terminate themselves; LBSMIC-2 is the same construction supplied as a finished patch cable with 3-pin XLR male and female connectors fitted at the factory.
Which conductor size should I choose?
2 × 0.3 mm² (≤55 Ω/km, 6.0–6.5 mm O.D.) suits standard microphone routing and patching. 2 × 0.5 mm² (≤40 Ω/km, 6.8–7.2 mm O.D.) is intended for long-distance routing where lower resistance and capacitance matter.
What is the difference between foil and braid shielding?
Foil gives broad high-frequency coverage; copper braid adds mechanical strength and a solid ground path. The LBS microphone range combines both in a double-shielded construction.
Can LBS custom-print my brand on microphone cable?
Yes, LBS supports OEM/ODM orders: custom jacket colours, brand/model printing, custom lengths and packaging. Contact LBS for project details.
Related Products
- LBSMIC-1-2X0.5 — 2-Core Shielded Balanced Microphone Audio Cable (bulk)
- LBSMIC-1-2X0.3 — 2-Core Shielded Balanced Microphone Audio Cable (bulk)
- LBSMIC-2-2X0.5 — Finished XLR Microphone Patch Cable
- LBSMIC-2-2X0.3 — Finished XLR Microphone Patch Cable
- Audio Signal Cable range