Shan E540

3-way floorstanding loudspeaker 2x7"+5"+1"

Original state

These loudspeakers arrived to me and after short listening it was obvious there is something wrong. Lean shy bass, somehow disconnected from the rest, shouty midrange and trebles which also seemed somehow disconnected, .... it is not what I would expect from dual Classic Scan Speak 18W woofers and Focal drivers. This short experience determined the upgrade. The goal was clear...to breath more life into this pair of very nice loudspeakers.

I was very curious to see what was inside, but first I made the measurements in the original state. After woofer removal, it was obvious loudspeakers were not in the state from factory.

Measurements were quite surprising, and they actually looked very good. FR measurement with reversed midrange showed that there was not crossover with full 6dB summation at crossover frequencies (Butterworth?). Nevertheless this was nice demonstration that good measurement is not the warranty of good sound.

Findings:

- Whole enclosure was heavilly stuffed with damping material, even more than I would you for closed cabinet.

- all crossover PCBs looked to be original, but were in terrible state, warped, oxidated, added components etc.

- everything, really everything, was covered with sticky bitumen pads. Each driver, each coil,.... Someone spent a lot of time to do that. And thank to that, it took me a lot of time to get tweeters from enclosured and clean drivers.

- terminals terribly oxidated and soldering was poor, I pulled wires from 3 of them, just easily by hand.

It became clear this will be full upgrade.

Following measurements were done with mic distance 1m, ref axis between mid and tweeter. Time window applied to impulse response ~4ms, no smoothing applied.

Horizontal FRs 0-90deg

Axial FR with correct midrange polarity in red, reversed mid in green.

Power response in blue, axial FR in gray, Directivity index in red (for ref angle 0°)

New measurements and crossover modelling

Crossover modelling was quite easy. There were troubles with impedance falling below 3Ohms, and Focal midrange had just enough sensitivity to keep up with dual Scan Speak woofers. The first version was more flat. And the sound? Not good, still quite lean bass, somehow disconnected, and certain harshness. So back to modelling and typical itteration of listening and crossover changes started. The result is bellow.