Celestion CS 135
A small black-ash subwoofer that Celestion built to give its little bookshelf speakers a bottom end — and a reminder that "subwoofer" in 1993 meant something modest.
Overview
The CS 135 is the bass box in what Celestion called the Trinity system, and the way the company packaged it tells you most of what you need to know. The system shipped as three compact pieces: a pair of Celestion 1 loudspeakers and a single CS 135 subwoofer, finished in simulated black-ash veneer and sold together for $399, according to Audio (July 1993, p.85). That price for a complete three-piece system is the whole story of the product — this was never a statement subwoofer. It was the affordable way to add low end to speakers that, on their own, had none to speak of.
The enclosure arrangement is the interesting part. The CS 135 uses a dual-chamber cabinet, sealed in front of the 8-inch driver and vented to the rear — a configuration that, per Audio's description of the Trinity system, lets a single 8-inch woofer behave as though it's working in a larger, more controlled volume than its box would otherwise allow. The front chamber is sealed against the driver; the rear chamber is ported.
Celestion's own advertising of the period framed the CS 135 as "an exceptional subwoofer designed to provide a deep yet subtle extended bass to the Celestion 1, 3, and 5 speakers," language that ran in Audio (July 1993, p.85) and HiFi-Stereo (March 1993, p.32), among others. Read that carefully: "deep yet subtle." That's manufacturer copy being honest about what the thing is. The CS 135 is not a home-theater earthquake generator. It's a support act — designed to fill in the bottom octave or so beneath small Celestion monitors without announcing itself as a separate box in the room.
The practical consequence, for anyone considering one today, is that the CS 135 is best understood as a system component rather than a standalone sub. It was voiced to integrate with the Celestion 1, 3, and 5 — the small two-ways of the range — and it does its best work when it's crossed in low and loudness-matched to speakers with limited bass extension of their own. Paired with a modern bookshelf that already reaches into the 50s, it will feel redundant. Paired with something like the Celestion 1 — a vented 4-inch woofer and 1-inch titanium-dome tweeter per Audio's (April 1994, p.74) description — it's the difference between a system that has a bottom and one that doesn't.
What Owners Actually Get
The honest caveats are worth stating plainly. The CS 135 was an affordable subwoofer in a period when affordable subwoofers were, by modern standards, small and gentle. It's a subtle extension, in Celestion's own framing, and that's the right expectation to bring to it.
The finish — simulated black-ash veneer — is period-typical and holds up reasonably if the cabinet hasn't been knocked around, but it's a vinyl wrap, not real wood, and it shows its age the way vinyl wraps do. Cosmetically clean examples are the ones to look for; cabinet damage on a $399 system sub is rarely worth repairing.
The system context matters for the market, too. That's fine if the goal is to add bass to a pair of small Celestions, but it means buyers are usually evaluating a single black box with no matching satellites — and that affects what people are willing to pay.
The Case For and Against
For: the dual-chamber design is a genuinely thoughtful piece of engineering for the price, the driver size and loading are well matched to the small Celestion speakers it was built to support, and the system price of $399 for three pieces was aggressive for what it delivered. It's the kind of product that made sense in a dealer's showroom and still makes sense in a small room today, provided the expectations are calibrated.
Against: it's an 8-inch subwoofer from an era when that meant modest output, the finish is simulated veneer, and it's a system component that's easy to overpay for in isolation.
The CS 135 is best appreciated for what it is: a small, honest, well-thought-out bass box that Celestion built to complete an affordable system, and that still does that job for anyone running a pair of small Celestion bookshelf speakers and wishing they went lower.
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