Peerless 831727
A ten-inch woofer that DIY builders bought twelve at a time — and that one builder drove to the displacement of a small-block V8.
Overview
The Peerless 831727 is a 10″ woofer — a CC line driver, in the catalog shorthand — that occupies an unusual place in the hobby: it's a component, not a finished product, and its reputation was built almost entirely by the people who stuffed it into boxes they built themselves. The published numbers are modest on paper. A rated impedance of 8 ohms, a catalog frequency range of 22–2,800 Hz, an Xmax of 9mm, and a power handling figure of 220 watts. It uses a shading ring to minimize inductance problems as frequency rises — a detail that matters more than it sounds, because inductance rise is what makes a woofer's upper range turn gritty and directionless, and the ring is part of why this driver can be crossed higher than a typical 10″.
That 22 Hz lower figure deserves a raised eyebrow. A 10″ driver in a closed box does not produce 22 Hz at any useful level, and the catalog range is exactly what the table header says it is — catalog-specified, not measured in a real enclosure. Treat it as the outer bound of what the driver will respond to, not a promise about what it will deliver in your cabinet. The honest number is the one that shows up in large-signal predictions: the 831727 modeled in a closed box lands with a system Qtc of 0.75 and a response anomaly of −5dB, and the predicted maximum SPL at 41 Hz comes in around 105 dB with roughly 80 watts of input. That's the real story of this driver — not a subwoofer, but a midbass unit with genuine linear excursion and the displacement to keep up with whatever sits above it.
The Xmax figure is the one collectors and builders keep coming back to. Nine millimeters of linear travel in a 10″ frame is generous, and it's the reason Tom Perazella, writing in Audio-Express (June 2004, p.19), chose the 831727 for a dipole midbass array after auditioning a range of other drivers. He needed volume displacement — a lot of it — to bridge the gap between a large subwoofer system below and planar magnetic drivers above, and he calculated that six of these per side would give him roughly 270 in³ of linear displacement, about three times what his single 12″ midbass had been providing. His line about it approaching the displacement region of a small-block V8 is the kind of thing a builder says when a driver has earned it.
The driver was widely available through Madisound and carried by Parts Express under catalog number 297-616, which is how most American builders encountered it. Perazella noted that Madisound had the twelve pieces he needed in stock when he ordered — a small aside that says something about how this driver was distributed. It wasn't exotic. It was stocked, orderable in quantity, and priced to be ordered in quantity. A costed bill of materials from that same build puts the 831727 at $54.35 each, twelve of them totaling $652.20 — the single largest line item in a project that ran to $1,556.18 all-in. For a driver that would anchor a serious dipole array, that's a working-man's price.
What it isn't is a plug-and-play replacement woofer. The 831727 wants a design that accounts for its Qts and its excursion, and the period literature is blunt about the tradeoffs. Closed-box designs using this driver land in the 0.7–1.0 Qtc range that most builders aim for, but the −5dB anomaly means the low end rolls off rather than slamming flat, and pushing for a lower F3 in a vented alignment gets difficult fast. The Audio-Express design coverage (October 2003, p.22) walks through the closed-box-versus-vented question directly, noting that matching box volume to the driver's equivalent compliance volume gives you a quasi-Butterworth third-order response with F3 and tuning frequency both above the free-air resonance — a polite way of saying the box will be smaller than you want and the bass will stop higher than you hoped. Builders who wanted 41 Hz at serious levels were told, in effect, to bring more drivers.
That's the calculus this woofer invites. One 831727 is a competent 10″ midbass with a shading ring, 9mm of travel, and a sensible 8-ohm load. Six of them are a wall of displacement. The driver's reputation rests on the second use case, and the fact that it was still turning up in yard-sale listings years later — four of them at $35 apiece in a 2003 classified, described as CC Line Peerless woofers covering 20Hz–500Hz — suggests they held up well enough that people kept passing them along rather than binning them.
For anyone hunting a pair today, the practical notes are these: the 8-ohm impedance and 220-watt rating make it easy to drive with ordinary solid-state amplification, and the shading ring means it can be crossed higher than a typical 10″ without the top end falling apart. The 9mm Xmax is the reason to buy it and the reason to give it a real box — a sealed enclosure of adequate volume, or a vented design that accepts the higher tuning that comes with it. Don't expect 22 Hz. Do expect a driver that was engineered to move air in quantity, sold at a price that made quantity possible, and documented well enough in the period press that a careful builder can still work out what to do with it.
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