ESB Audio 5.6K3 CX — 5000 Series 3-Way Passive Crossover (pair)

ESB Audio 5.6K3 CX — 5000 Series 3-Way Passive Crossover (pair)

The 5.6K3 CX is the three-way passive network for the ESB 5.165 mid-woofer, 5.050 dome midrange, and 5.028 tweeter — or for the 5.165 paired with the 5.UMA, which carries the same midrange and tweeter on one flange. It divides at 900 Hz and 3.6 kHz and handles 300 W. Sold as a pair.

Two Crossover Points, Three Filter Types

The network uses a different filter order on each section, and the reasoning is visible in the driver data:

• Low-pass, 12 dB/oct Butterworth — rolls the 5.165 off above 900 Hz
• Band-pass, 6 dB/oct — passes the 5.050 between 900 Hz and 3.6 kHz
• High-pass, 12 dB/oct Butterworth — opens the 5.028 above 3.6 kHz

The gentler 6 dB/oct band-pass on the midrange is deliberate. A dome midrange sitting between two other drivers is overlapped at both ends, and a shallow filter lets it blend into its neighbours over a wider region rather than handing off abruptly. It works because the driver has genuine bandwidth on both sides of its assigned band — the 5.050 is rated 600 Hz to 5 kHz, comfortably wider than the 900 Hz to 3.6 kHz it is being asked to cover.

Every crossover point here sits inside what the drivers are rated for at the slopes used. The 900 Hz low crossover clears the 800 Hz floor the 5.050 requires with a shallow filter, and the 3.6 kHz high crossover is well above the 2 kHz limit of the 5.028 at 12 dB/oct.

Why Three Ways

Moving the midrange onto its own driver takes the vocal band off the door.

In a two-way, the 6.5-inch woofer covers everything from its high-pass up to 2.1 kHz — which means voices come from a driver mounted low in a door, working into a cavity the vehicle manufacturer did not design as an enclosure. In a three-way, that band moves to a dome that can be mounted at or near ear height, in a proper sealed volume, radiating evenly off-axis.

The stage rises, the vocal range gets easier to place, and the woofer is left to do the one thing a door-mounted 6.5-inch driver does well.

Component Choices

The capacitors use polypropylene or Mylar dielectrics. Film capacitors hold their value as they age where electrolytics drift — which matters more in a three-way than a two-way, because there are two crossover points and more components whose interaction defines the response.

Level Adjustment on Both Upper Sections

Two independent trims:

• Midrange: 0 / −2 dB
• Tweeter: 0 / −3 dB

This is the practical advantage of the three-way network. In a two-way the only balance available is between bass and treble; here the midrange can be set relative to both. A vocal range that sits forward in one vehicle and recessed in another can be corrected at the crossover, and the tweeter trimmed separately after that.

Set both in the vehicle, with the doors closed, from the listening position. They interact — pulling the midrange down changes how the tweeter reads.

System Application

A 5000 Series three-way running one amplifier channel per side. It works with either mid-high arrangement: separate 5.050 and 5.028, or the co-located 5.UMA.

Buying the drivers as the 5.6K3 or 5.6K3U and adding this network produces the same system as the 5.6K3X and 5.6K3UX, which include it.

An active three-way run from a DSP does not need it — the processor provides adjustable crossover points, steeper slopes, and time alignment between all three drivers. In a three-way that alignment is worth considerably more than it is in a two-way, because there are three arrival times to reconcile instead of two.

Installation Considerations

The network measures 136 × 99 × 35 mm — larger than the two-way, as it must be. Plan a location that keeps the level switches reachable once trim is refitted.

Terminals accept cable up to 4.5 mm (6 AWG).

Wiring is six conductors per side out of the network — woofer, midrange, tweeter. Check polarity on all three. In a three-way, a reversed midrange creates cancellation at two crossover points rather than one, and the resulting hole in the response is easy to mistake for a driver fault.

Keep the network away from amplifier heat and power cabling.

Specifications

• Type: 3-way passive crossover network
• Crossover frequencies: 900 Hz / 3.6 kHz
• Slopes: 12 dB/oct low-pass Butterworth · 6 dB/oct band-pass · 12 dB/oct high-pass Butterworth
• Mid-frequency level: 0 / −2 dB
• High-frequency level: 0 / −3 dB
• Capacitors: polypropylene or Mylar dielectric
• Low-frequency section: ESB 5.165
• Mid-frequency section: ESB 5.050
• High-frequency section: ESB 5.028
• Power handling: 300W
• Cable connector: up to 4.5 mm (6 AWG)
• Dimensions: 136 × 99 × 35 mm
• Sold as: pair

HF Audio Perspective

The interesting thing about this network is the 6 dB/oct band-pass on the midrange, because it tells you what ESB was after.

A steeper filter would have kept the midrange more strictly inside its band and made the design safer. The shallow one lets it overlap generously with the woofer below and the tweeter above, which asks more of the driver and, done well, produces a more continuous transition through the range where the ear is most sensitive to discontinuity. It only works because the 5.050 has real bandwidth to spare on both sides — which it does, rated from 600 Hz to 5 kHz for a job spanning 900 Hz to 3.6 kHz.

Where we would be honest is on the comparison with active. A three-way has three drivers at three different distances from the listener, and no passive network can correct that; a DSP can. If the system will eventually run active, the drivers are the lasting purchase and this network is the interim step.

If it will stay passive, this is a properly designed network with the crossover points chosen against the datasheets, film capacitors that will hold their values, and independent level trim on both upper drivers. Use those trims. They are the only adjustment the system has.