Key Features
The “CSX” designation identifies this driver as incorporating a shorting ring in the magnetic circuit — a flux-distortion-reduction technique that lowers second-order harmonic distortion and reduces the modulation of voice coil inductance as the driver moves. This places the CSX-217H a step above the equivalent CSC (non-shorting ring) version in terms of low-distortion performance, and makes it particularly well suited to wide-range applications where the driver is expected to cover bass and lower-midrange frequencies in a single unit.
The cone itself is a multi-layer sandwich construction — a bonded composite structure offering higher internal damping and greater stiffness than a single-layer paper cone — combined with a high-compliance rubber roll surround. Rubber surrounds of this type are considerably more durable than polyurethane foam alternatives and are not subject to the surround deterioration that affects drivers from the same era with foam surrounds.
The motor assembly is substantial: a 102mm magnet with a measured flux density of 0.95 Tesla and a four-layer 33mm voice coil wound in a 6mm gap. The resulting force factor (Bl) of 10.4 N/A is high for an 8″ domestic woofer, contributing to good control, low Qts of 0.27, and an exceptionally low resonance frequency of 28.2Hz — a figure more typical of a dedicated subwoofer driver than a general-purpose 8″ unit. This combination makes the CSX-217H highly effective in vented (ported) enclosures, where it can produce genuinely extended bass from a reasonably compact cabinet.
Its published crossover range of 1,500–3,000Hz and smooth midrange response also make it viable in a two-way system, which is relatively unusual for a driver of this size and excursion capability. Recommended ported cabinet alignments range from 25 litres (port: 70mm diameter, 120mm length, tuned to approximately 50Hz) up to 60 litres (port: 70mm diameter, 65mm length, tuned to approximately 40Hz with extension to –3dB at approximately 40Hz). The mounting screws removed from the donor enclosure are included with this driver.
Technical Specifications
(Source: Official Peerless datasheet for Cat. No. 850136, confirmed via DST-AU spec sheet reproduction. All figures are manufacturer’s published values unless otherwise noted.)
- Type: 8″ bass woofer drive unit; multi-layer sandwich cone; rubber roll surround; inverted dust cap
- Catalogue number: 850136
- Nominal impedance: 8Ω
- DC resistance (Re): 5.9Ω
- Minimum impedance: 6.6Ω (at 188Hz)
- Voice coil inductance (Le): 2.6mH
- Resonance frequency (Fs): 28.2Hz (measured: 27.4Hz)
- Mechanical Q (Qms): 3.50
- Electrical Q (Qes): 0.29
- Total Q (Qts): 0.27
- Equivalent volume (Vas): 79.7 litres
- Effective cone diameter: 173mm
- Effective piston area (Sd): 235 cm²
- Force factor (Bl): 10.4 N/A
- Moving mass (Mms): 30.5g
- Sensitivity: 89.5dB (2.83V/1m, referenced at 188Hz)
- Power handling: 150W IEC (long-term)
- Voice coil diameter: 33mm; 4-layer winding
- Magnet diameter: 102mm; weight 0.68kg
- Flux density in gap: 0.95T
- Country of origin: Denmark (confirmed on unit label)
Summary
This is a single-unit listing. The Peerless CSX-217H is a well-specified, professionally engineered Danish-made driver that has accumulated a strong following in the DIY speaker building community since its introduction. Its combination of very low Fs, high force factor, shorting ring motor, and wide crossover range make it a genuinely versatile woofer capable of delivering performance well beyond its modest footprint. Mounting screws are included. Please feel free to get in touch with any questions prior to purchase.
