Subwoofer cables explained: what you need, what's marketing
Good news for your wallet: the cable is the one part of a subwoofer system where spending more buys nothing audible. Here's which connection your setup needs, and the two specs that actually matter.
Which connection is yours?
- LFE / “Sub Out” (most common): one RCA cable from the receiver's subwoofer output to the sub's LFE input. Mono, simple, correct. This is what 90% of readers need.
- Line-level L/R: subs without an LFE input take left and right RCA. From a receiver sub-out, use a Y-splitter into both inputs if the manual recommends it; from a stereo preamp, run L and R.
- High-level / speaker-level: the sub taps your amplifier's speaker terminals (REL's speciality, using a supplied Neutrik cable). No RCA run needed; the sub inherits the amp's character. Used in stereo systems without a sub output.
- XLR (balanced): studio subs (like the JBL LSR310S) and some high-end models. Inherently hum-resistant — the right choice when the gear has it, irrelevant when it doesn't.
- Wireless kits: replace the signal cable entirely — covered in the wireless guide.
The two specs that matter
- Shielding. Subwoofer runs are long and live on the floor near power cables. A dual-shielded cable prevents the hum and buzz pickup that cheap unshielded wire invites. This is the one quality difference worth paying a few dollars for.
- Length — measured, not guessed. Route along walls, not diagonally across the room, and add a metre of slack. Line-level signals are happy at 10–15 m, so buy the length you need; don't coil five spare metres behind the sub (a tidy excess invites interference pickup for no benefit).
What's marketing
Directional arrows, oxygen-free copper grades, cryogenic treatment, braided sleeves beyond abrasion protection — none of it changes a 40 Hz line-level signal. The honest hierarchy: any shielded cable of the right length ≫ routing it away from power cables ≫ everything else combined. Put the savings toward an isolation platform — an accessory that audibly does something.
Setup after the cable
Once connected, the sound quality lives in three dials — crossover, gain, and phase. The three-dial setup guide takes fifteen minutes and matters roughly a hundred times more than the cable did.
Frequently asked questions
Do expensive subwoofer cables sound better?
No — a subwoofer cable carries a low-frequency line-level signal, the least demanding job in audio. What matters is adequate shielding (to prevent hum pickup on long runs) and the right length. A well-made $15–25 cable performs identically to a $200 one.
Can I use a normal RCA cable as a subwoofer cable?
Yes. 'Subwoofer cable' is a standard shielded RCA interconnect, usually thicker and longer. Any decent shielded RCA cable works; the dedicated ones are simply built for long floor runs with better shielding against hum.
Do I need a Y-splitter for my subwoofer?
Only if your subwoofer has separate L and R line inputs and no LFE input, or if its manual says a Y-adapter raises input level. With a receiver's dedicated subwoofer output into an LFE input, a single cable is correct — the receiver already sums the bass to mono.
What causes subwoofer hum and does the cable fix it?
A steady 50/60 Hz hum is usually a ground loop, not a bad cable — fix it by plugging the sub and receiver into the same outlet/strip, or with an isolation transformer on the cable. Buzz that changes when lights dim is interference pickup, where better shielding or rerouting away from power cables genuinely helps.