<\/p>\n
As in real life, loudspeaker building can take a sharp turn and the Excellence Two \u2013 Mini Monitor is no exception.<\/p>\n
When I listened and tested the loudspeaker with my DEQX in an active setup it sounded fantastic. It worked best when I used a 48dB\/octave linear-phase cross-over with a cross-over point between 1750-2000Hz.<\/p>\n
With that in mind I started to design and build a first prototype of the cross-over with steep cross-over slopes (4th-order LR, acoustical) and with a cross-over point around 2-2.1kHz.<\/p>\n
Everything was looking good, both frequency and distortion measurements, but something was missing\u2026. Yes, the loudspeaker sounded good, but the magic was gone!<\/p>\n
I used a “Sledgehammer” Steel Laminate Inductor for the mid-woofer section of the cross-over in order to keep the inductors \u201cDCR\u201d as low as possible. I quickly swapped this inductor to a 12 AWG copper-foil inductor instead (expensive).<\/p>\n
The effect surprised me. Now the loudspeaker sounded much better. Some muddiness disappeared and the mid-range clarity was much better, but still no magic! I expected more of these drivers after listened to them in the active setup.<\/p>\n
First of all, even though these “Sledgehammer” Steel Laminate Inductors have a good reputation they will never be used as a cross-over part in one of my designs. Perhaps they would work in the woofer section of a 3-way cross-over, but I would never use them in any mid-woofer or mid-range section of a 2 or 3-way system. They have poor sonic performance in my opinion and when using a high resolution driver as the SEAS Excel, they just don\u2019t work in this design.<\/p>\n
What to do? Scrap the project\u2026\u2026. Of course not! Back to the drawing table and build the v2.0 cross-over.<\/p>\n
Ok, a steep passive cross-over for the W12CY001 mid-woofer killed the midrange resolution and even though the cap shunt over the inductor technically worked in reducing the 10kHz cone break-up, it didn\u2019t sound good enough.<\/p>\n
This time I simplified the cross-over even further. I used a single inductor together with a LC notch to reduce the cone-break-up at 10kHz. Now the acoustical cross-over slope is a 2nd order LR topology. The mid-woofer section has the same number of cross-over components, but the components connected in series with the signal path are reduced to one. That\u2019s a good thing sonically.<\/p>\n
The tweeter section only needed a minor change to fit the new design. It was as simple as removing one cap and the new cross-over only needs 8 components to achieve the desired cross-over point at 2100Hz.<\/p>\n
The v2.0 cross-over consist of a single inductor (L1) and with the above mentioned LC (C1, L2) notch-filter for the mid-woofer section. The tweeter uses a single cap + inductor (C2, L3) and has a response shaping circuit ( C3, R2) in order to reduce the tweeters rising top-end. The single resistor (R1) is used to attenuate the tweeter level to an appropriate level and personal taste.<\/p>\n
The cross-over is an asymmetrical filter design with a mid-woofer acoustical 2nd order topology and a tweeter 3rd order topology. The asymmetrical filter design together with the relative acoustical off-set between the mid-woofer and the tweeter makes a perfect acoustical 2nd\u00a0 LR cross-over filter with a 180deg phase shift at the cross-over point, which means that the tweeter must be connected in reverse polarity.<\/p>\n
<\/p>\n Left picture:<\/strong> Cross-over v1.0<\/p>\n Right picture:<\/strong> Cross-over v2.0<\/p>\n <\/p>\n <\/p>\n Left picture:<\/strong> System — 85dB @ 1m<\/p>\n Right picture:<\/strong> System — 90dB @ 1m<\/p>\n A tiny bit higher distortion numbers compared to the v1.0 cross-over, but it’s still very low.<\/p>\n <\/p>\n![\"\"](\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/12\/Cross-over-v1.0.jpg\" "\\"Cross-over")
<\/a>![\"\"](\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/12\/Cross-over-v2.0.jpg\" "\\"Cross-over")
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