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Product: XM126-3 Crossover with PS127 power supply
Manufacturer: Marchand Electronics
Price: As tested $US4200
$2700 (2-way) $+500 (balanced option)
$3500 (3-way) $+700 (balanced option)
$4500 (4-way) $+900 (balanced option)
there are also options for 24 position attenuators instead of 12 position.
These are big heavy things that are substantially packed and therefore expect high insured shipping charges (these were $400 two years ago). YMMV depending on current shipping and exchange rates
Author: Mark Wheeler - TNT UK
Reviewed: Spring 2023 to Spring 2024

Getting Active and Getting Warm

Marchand Electronics are based in Rochester NY, a town brimming with technological skills and home of RIT. There must be something in the air or the water in Rochester because Marchand have one of the most interesting and specialised ranges of audio electronics. Spoiler alert: few audio products have given as much joy of ownership as this crossover because it is a massive risk buying very expensive audio equipment unseen and unheard. Your Old Scribe is more than satisfied with this purchase. If I hadn't built my own power amps to match the drivers, I would probably buy Marchand's own.

I first spotted the ads for Marchand electronic crossovers in the now defunct Speaker Builder magazine when your Old Scribe wrote for them over 25 years ago. Marchand make a range of active and passive line level crossovers and other audio and test gear. The crossover range includes models with variable Q filters for fine tuning and system development. The model I wanted to try is fully balanced and all triode. While not being a subscriber to any amplification religious zealotry, your Old Scribe generally finds simple triode circuits to be more predictable in performance and universal in application. Fewer gain stages and more headroom, big voltages and small currents, all seem to be a sensible starting point at line level.

When children play hide and seek they talk about “Getting warm” as the seeker gets close to the prize. The Marchand XM126-3 Crossover gets the Old Scribe Euterpe system closer to the prize and being all valve (tube) is physically warm too. The resident 3-way Euterpe Loudspeaker system has been unchanged for a long time. Long enough to be confident of the chosen crossover frequencies and slopes, so a commitment can be made.

“What Commitment is that?” demand cynical Plebs, stage left

The Marchand XM126-3 requires a new set of filter modules installing if crossover frequencies and slopes are to be altered. Their standard configuration is 4^th order Linkwitz-Riley, which happens to be the final choice of the Euterpe system after some experiments and faffing about. Fourth order crossovers ensure that the drivers are in phase with each other at the crossover frequency. Steeper filters do have twice the phase shift per octave of second order filters. This is additional to the inherent phase shift within each driver (dominated by its inductance) and any multi-way moving coil loudspeaker is a compromise of physical shape and electrical characteristics. Your Old Scribe is increasingly of the opinion that the L-R filter should be the default choice unless designing for particular vertical lobing.

Description and function

In multi-way loudspeaker systems (whether moving coil drivers, electrostatic, isodynamic, ribbon or whatever) a crossover is needed. The crossover limits the frequency range of the amplified signal delivered to the terminals of each driver. The bandwidth (the permitted frequencies from low to high) sent to each drive unit is defined by what that driver is designed to handle in that baffle, box or horn. Most commercial domestic loudspeakers do this dividing inside the box, using big components (capable of handling the rated power input) between the input terminal block and the drivers. For a variety of reasons this is a fairly daft legacy practice in the 21^st century when inexpensive amplification is more cost-effective than massive inductors and capacitors, hence your Old Scribe's rant here against the passive crossover. The alternative is to divide the frequencies at line level stage and match power amplifiers to each driver's needs.

Your Old Scribe first built a loudspeaker expressly for active configuration in the late 80s, using Decca London Ribbon and Focal 10N501 drive units. That all solid state Naim based system revealed the full advantages of active configuration. An exact match (voltage at driver terminals) premium passive crossover equivalent measured identically but was obviously audibly compromised in comparison. As voice coil temperature fluctuates under power, so does its impedance and thus frequency response and phase accuracy.

Setting Up

Obviously this is one of the second most complicated task you'll ever encounter in audio. The most challenging task in audio is finding the best compromise of loudspeaker placement. Crossover alignment has to come second to that, even when frequencies and slopes have already been established. With a bass-mid crossover point of 240Hz issues like baffle step, floor reinforcement and wall reinforcement are the preserve of that channel. Early reflection is the preserve of mid and top drivers. This actually enables a little flexibility in placement. Having already established flat response and optimum placement with the Behringer, set up began with a calibrated microphone and REW software.

Once the best compromise was reached for flattest response in as many listening seats as possible, some subjective treaks were applied. The Marchand XM126-3 Crossover is illustrated sitting directly on top of the PS127 power supply on the Marchand website. It does perform better when a suitable light shelf is inserted between them. In this instance the now obsolete ERAudio SpaceHarmoniser worked perfectly. Connections are all using balanced to balanced leads or balanced to single-ended adapters for HF and midrange amplification as below.

Sound Quality

In Part 2 we'll hear what it all sounds like.

Copyright © 2024 Mark Wheeler - mark@tnt-audio.com - www.tnt-audio.com

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