ESB Audio MB Coax 100 — Coaxial Speakers for Mercedes-Benz

ESB Audio MB Coax 100 — Coaxial Speakers for Mercedes-Benz

The MB Coax 100 is the coaxial member of ESB's 6000 Series Car Special range for Mercedes-Benz — a 4"/100 mm two-way driver with the tweeter on the woofer's axis, rated 60 W continuous and 120 W peak at 4 ohms, covering 75 Hz to 22 kHz at 89 dB sensitivity.

Direct fit to a factory coaxial location — factory mounting, factory connector, no adapters. Sold as a pair.

Coaxial or Component — the Car Decides, and the Numbers Are Close

This is not a lesser version of the MB Front 100. Put the two datasheets side by side and they are trading, not ranking:

• MB Coax 100: 89 dB @ 1W, 75 Hz – 22 kHz, 6.025 g moving mass, 0.470% reference efficiency
• MB Front 100: 88 dB @ 1W, 75 Hz – 25 kHz, 7.128 g moving mass, 0.356% reference efficiency

The coaxial is the more efficient of the two — a decibel louder for the same power, and meaningfully higher reference efficiency, because its moving assembly is lighter at 6.025 grams. The component set reaches three kilohertz higher, because it carries a dedicated silk dome tweeter that can be optimized independently of the woofer.

On a factory amplifier with limited output, that efficiency advantage is not a footnote. Which one to buy is decided by what the vehicle's location provides, not by which datasheet looks better.

What Coaxial Geometry Gives You

Mounting the tweeter on the woofer's axis has a genuine acoustic advantage, and it is the opposite of the one people expect.

Both drivers radiate from the same point, so their outputs arrive at the listener at the same time from the same place. There is no path-length difference to correct and no crossover region where the two drivers pull the image in different directions — which is exactly the problem a separately mounted tweeter creates when it ends up in a different panel from its woofer.

What you give up is the ability to aim the tweeter independently. In a location where you could not have aimed it anyway, that costs nothing.

It is the same reasoning that makes ESB's UMA units attractive higher up the range, applied at a different scale.

The Driver Itself

Moving mass is 6.025 grams across 52.81 cm² of cone area, driven by a motor developing 6.500 N/A. Free air resonance is 107.8 Hz and Qts is 0.354.

Those numbers describe a driver built to be quick and efficient rather than to move air — which is the correct priority for a 4-inch driver in a factory location that has a subwoofer working beneath it. With 1.43 litres of Vas and a tightly loaded factory cavity, this is a midrange and treble device by design.

Why Direct Fit Matters in a Small Opening

A 100 mm location has almost no spare depth, which makes the usual adapter approach worse here than in a door.

An adapter ring consumes depth the opening does not have and creates a joint that leaks unless it is sealed — letting the driver's rear output wrap to the front and cancel the modest low-frequency output a small cone produces. Proportionally, that loss hurts a 4-inch driver far more than a door woofer.

A spliced harness adds a connection that did not exist when the car was built.

Working on Factory Power

The factory amplifier's output does not change when the speakers do, which is why the 89 dB figure matters more than the 60 W rating these drivers will never see.

The factory equalization does not change either. It was written around the drivers being removed, and new speakers inherit that curve — the improvement is real because the new drivers have headroom the correction is not demanding, but the factory tonal signature stays underneath. A processor is what removes it, and that is a separate stage.

System Application

Mercedes-Benz factory coaxial locations — depending on the vehicle, that may be rear doors, a parcel shelf, or front positions.

Where the car's front location takes a separate woofer and tweeter, the MB Front 100 is the correct part. Where the vehicle has factory subwoofer positions, the MB Sub 200 covers those — and coaxials plus factory-position subwoofers is a coherent full-vehicle upgrade, with the crossover between them landing naturally around the coaxial's 75 Hz limit.

Confirming Fitment

"Mercedes-Benz" is not a fitment, and we would rather say so than take an order that has to be unwound.

The range covers many models, generations, and factory audio packages. Speaker size, position, count, and connector vary between all of them — a C-Class and an E-Class of the same year can be different installations, and a premium-system car is different again from a base car of the same model.

Before ordering, send us the model, generation, model year, and factory audio package, or simply the VIN. We will confirm the part before anything ships.

Installation Considerations

Disconnect the battery before removing trim. Mercedes panels carry wiring that may include airbag circuits.

Seal around the driver. In a coaxial this small, an unsealed opening costs a larger share of the total output than it would in a door woofer.

Do not high-pass below 75 Hz. The driver's response starts there and its 1.43 litres of Vas is not an invitation to go lower.

If the location is a parcel shelf or a shallow door pocket, confirm nothing has been changed by a previous installation before ordering — direct fit means the driver matches the factory specification, not whatever is in the car now.

Specifications

• Type: vehicle-specific 2-way coaxial speaker
• Series: ESB 6000 Series Car Special
• Vehicle: Mercedes-Benz — confirm model and factory audio package before ordering
• Nominal diameter: 4"/100 mm
• Nominal impedance: 4Ω (Re 3.79Ω)
• Power handling: 60W continuous · 120W peak
• Frequency response: 75 Hz – 22 kHz
• Sensitivity: 89.0 dB @ 1W/1m · 92.0 dB @ 2.83V/1m
• Reference efficiency: 0.470%
• Free air resonance (Fs): 107.8 Hz
• Qes 0.366 · Qms 10.680 · Qts 0.354
• Vas: 1.428 litres · Mms: 6.025 g · Cms: 0.362 mm/N
• BL: 6.500 N/A · Sd: 52.81 cm²
• Fitment: direct — factory mounting and connector, no adapters required
• Sold as: pair

HF Audio Perspective

Coaxials carry a reputation as the budget option, and in the aftermarket that reputation is often deserved. Here the datasheet says otherwise.

This driver is a decibel more sensitive than its component sibling and carries a third more reference efficiency, because ESB got a full gram of mass out of the moving assembly. On a factory Mercedes amplifier with modest output, efficiency is the specification that decides how the system behaves — and by that measure the coaxial is the stronger of the two.

What the component set has is three kilohertz of additional extension and a silk dome tweeter you can aim. Both are worth having when the car gives you somewhere to put a tweeter. When it does not, a component set does not become a component set — it becomes a coaxial with the tweeter stuck somewhere it does not belong, which is worse than a properly designed coaxial in every respect.

Buy this because it is what the location takes, and take the efficiency as a bonus rather than a consolation. Then confirm the fitment before you order — on the Mercedes range, that step is not a formality.