ESB Audio 8.028S — 8000 Series 1.1"/28 mm Squared Silk Dome Tweeter (pair)

ESB Audio 8.028S — 8000 Series 1.1"/28 mm Squared Silk Dome Tweeter (pair)

The 8.028S is the ESB 8000 Series tweeter with the cut-off faceplate — a 1.1"/28 mm driver rated 110 W continuous and 220 W peak at 4 ohms, 91 dB sensitivity, recommended amplifier range 40 to 150 W RMS. Sold as a pair.

The driver is identical to the round-faceplate 8.028. ESB's datasheet covers both models together and states the difference plainly: the faceplate is available as a round type (8.028) or a cut-off type (8.028S). Everything behind it is the same part.

The Faceplate Is Removable — and That Is the Point

The front faceplate is CNC-machined from 7000-series aluminium alloy, and it unscrews and can be replaced.

That is worth understanding before choosing between the two versions. The round 8.028 measures 64 mm across. The 8.028S is 64 × 58 mm — the same driver with one side taken flat, so it seats where a round flange would foul an edge, a trim line, or an adjacent panel.

Because the plate is a serviceable part rather than a moulded-in feature, a tweeter can be adapted to a mounting location rather than the location being cut to suit the tweeter. In a fabricated A-pillar or a tight OEM opening, that is a real advantage.

The Torcon Dome

The dome is ESB's Torcon soft dome — an exclusive polyphenylene sulfide (PPS) with high-performance fibres.

PPS is specified here for three properties: heat resistance, low weight, and self-damping. The last is the one that matters acoustically. A dome material with high internal losses absorbs its own resonances rather than storing and re-releasing them, which is what produces a response free of break-up peaks across the audible range. Heat resistance matters because a tweeter's power limit is thermal before it is anything else.

Note that ESB's datasheet header describes the driver as a silk dome while the construction notes specify Torcon PPS. The PPS specification is the detailed one.

Motor and Distortion Control

An N52 oversized neodymium magnet — among the strongest grades available — drives a 28 mm voice coil on an aluminium former. ESB specifies 28 mm as the compromise between the low mass of a 25 mm coil and the power handling of a 32 mm one, with the aluminium former conducting heat away from the winding.

The magnet's metal parts were shaped through FEM analysis to concentrate flux around the coil and hold it linear through the full excursion. The pole plate is ultra-low-carbon alloy steel machined by CNC, which ESB specifies for flatness — a plate that does not sit perfectly on the magnet loses flux across the gap.

A pure copper ring sits in the magnetic circuit to reduce harmonic distortion, and dB Cloth damping beneath the dome absorbs residual resonances, extending response at the bottom of the band.

The Vented Motor

Ventilation runs through a large opening in the bottom of the motor, behind a filter with calibrated holes.

That vent does something specific: it lowers the impedance peak at the driver's resonance, which makes the tweeter easier for a passive crossover to work with. A tall impedance peak near resonance is exactly what makes passive networks behave unpredictably close to the crossover point.

With a free air resonance of 540 Hz and a Qts of 0.413, this driver resonates well below where it will be crossed — which is part of why it can be used down to 1.2 kHz behind a steep filter.

System Application

ESB publishes the usable band against filter slope:

• 1.2 kHz – 25 kHz with 48 dB/oct high-pass
• 1.6 kHz – 25 kHz with 24 dB/oct high-pass
• 2 kHz – 25 kHz with 12 dB/oct high-pass

It is the tweeter in the 8.6K2S and 8.6K3S systems, and it works with the 8.6K2 CX passive crossover, which is designed for the 8.165 or 8.165 LE woofer paired with either the 8.028 or 8.028S.

Run actively from a DSP, the 1.2 kHz figure becomes available and takes load off the midrange or woofer beneath it.

Installation Considerations

Choose between 8.028 and 8.028S on mounting geometry alone. The performance is identical — select whichever faceplate seats correctly in the location, and do not treat one as the better driver.

The unit is 64 × 58 mm at the flange with roughly 13 mm of front projection. A light stainless steel grille protects the dome.

Aiming matters more than the mount. A tweeter fired straight across the cabin puts a strong early reflection into the listening position; one aimed toward the listener, or at a shallow angle to balance near and far sides, gives a more stable image. Test angles before finishing the pods.

Never run it without a high-pass filter, and set that filter to the slope table above. Low frequencies destroy tweeters, and they do it quickly.

Specifications

• Type: component tweeter
• Nominal diameter: 1.1" / 28 mm
• Dome: Torcon PPS soft dome with high-performance fibres
• Faceplate: cut-off type, CNC 7000 aluminium alloy, removable and replaceable
• Magnet: N52 oversized neodymium
• Nominal impedance: 4Ω (Re 3.4Ω)
• Power handling: 110W continuous · 220W peak
• Recommended amplifier power: 40–150W RMS
• Sensitivity: 91.0 dB @ 1W/1m · 94.0 dB @ 2.83V/1m
• Free air resonance (Fs): 540 Hz
• Qes 0.928 · Qms 0.744 · Qts 0.413
• Voice coil: 28 mm, aluminium former
• Design bandwidth: 1.2kHz–25kHz (48dB/oct) · 1.6kHz (24dB/oct) · 2kHz (12dB/oct)
• Faceplate dimensions: 64 × 58 mm
• Sold as: pair

HF Audio Perspective

This product exists so that a mounting problem does not become a driver decision, and that is a more thoughtful bit of product planning than it first appears.

Tweeter placement is one of the few installation choices that genuinely changes how a system images, and it is usually constrained by what the vehicle allows. When the only good location has an edge or a trim line where a 64 mm round flange would sit, the usual outcome is a compromise — a worse position, or a modified panel. A flat side on the faceplate removes that trade entirely.

Because the plate unscrews, this is also a driver that can be adapted later. A build that moves to a different vehicle, or a pillar that gets refabricated, does not need a new tweeter.

Everything that determines how it sounds — the Torcon dome, the N52 motor, the copper ring, the vented magnet — is identical to the round version. Choose on geometry, and spend the attention on where it points instead.