<\/p>\n
The cross-over components is mounted on a double sided circuit board attached on the backside of the 5-way binding post.<\/p>\n <\/p>\n The cross-over is rather minimalistic with few components.<\/p>\n The tweeter cross-over filter section consists of one resistor (R1<\/strong>) together with an\u00a0electrical second-order (C1 + L1<\/strong>) high-pass filter that shapes the cross-over slope to a LR4 roll-off with a targeted 3.3kHz cross-over point.<\/p>\n The mid-woofer cross-over filter section have an electrical first-order (C2<\/strong>) high-pass section and an\u00a0electrical first-order low-pass section, which consists of a coil (L2<\/strong>) paired with an impedance equalization circuit (R2+C3<\/strong>) that shapes the cross-over slope to a LR4 roll-off with a targeted 3.3kHz cross-over point.<\/p>\n The sub-woofer cross-over filter consist of an electrical second-order (L3+C4<\/strong>) low-pass section together with a resistor (R3<\/strong>) in parallel with the sub-woofer. The sub-woofer is connected with reverse polarity.<\/p>\n <\/p>\n (click on picture to zoom)<\/p>\n The cross-over components consist of ceramic resistors, electrolytic caps, steel laminate coils (L1+L3<\/strong>) and an air-core coil (L2<\/strong>). They are of simple, but fair quality and are in fine condition. The caps (C1+C3<\/strong>) have a +\/- 5% tolerance, while the caps (C2+C4<\/strong>) have a +\/- 10% tolerance.<\/p>\n They all seem to be within acceptable tolerances even though more expensive components would probably have better compliance with the specification.<\/p>\n I can\u2019t see any other reasons but space and cost saving reasons why the (L1<\/strong>) uses a steel laminate coil rather than an air-core coil. It wouldn’t fit on the circuit board if it used an air-core coil.<\/p>\n <\/p>\n The cross-over simulations below are made using the raw in box driver measurements and simulates the on-axis frequency response at a 3m listening distance.<\/p>\n The sub-woofer frequency response are made of the summed near field response of the sub-woofer and port. The shown sub-woofer frequency responses don\u2019t include the influence of the room.<\/p>\n (click on picture to zoom)<\/p>\n Top:<\/strong> Simulated on-axis response @ 3m, 11cm above mid-woofer (Sub-woofer nearfield below 275Hz)<\/p>\n Middle left:<\/strong> On-axis response @ 3m, mid-woofer height.<\/p>\n Middle right:<\/strong> On-axis response @ 3m, 11cm above mid-woofer.<\/p>\n Lower left:<\/strong> On-axis response @ 3m, mid-woofer height, tweeter reverse polarity.<\/p>\n Lower right:<\/strong> On-axis response @ 3m, 11cm above mid-woofer, tweeter reverse polarity.<\/p>\n The optimal listening height is about 10-12cm above the mid-woofer center. The reverse polarity simulation shows a deep reverse null indicating a good phase tracking between the tweeter and mid-woofer. The cross-over point between the tweeter and the mid-woofer seems to be spot on the specified 3.3kHz.<\/p>\n Sub-woofer nearfield frequency response:<\/strong><\/span><\/p>\n <\/p>\n (click on picture to zoom)<\/p>\n Top:<\/strong> Summed sub-woofer + port nearfield response. Red<\/strong> without x-over and Blue<\/strong> with x-over.<\/p>\n Lower left:<\/strong> Summed sub-woofer + port nearfield response. Red<\/strong> without R3<\/strong>.<\/p>\n Lower right:<\/strong> Sub-woofer impedance. Red<\/strong> without R3<\/strong>.<\/p>\n As can be seen on the above frequency responses the cross-over adds about 3dB centered at 75Hz. If R3<\/strong> is omitted, additional 2dB is added, but the minimum impedance is also lowered.<\/p>\n![\"\"](\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2016\/08\/2.5i_Pic13.jpg\")
<\/a>![\"\"](\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2016\/08\/2.5i_Pic14.jpg\")
<\/a><\/p>\nThe cross-over schema:<\/span><\/h3>\n
<\/a><\/p>\nThe cross-over components:<\/span><\/h3>\n
<\/a><\/p>\nCross-over simulation:<\/strong> <\/span><\/h3>\n
<\/a>
\n<\/a><\/a>
\n<\/a><\/a><\/p>\n<\/a>
\n<\/a><\/a><\/p>\n