Pro 2-Way 24dB/oct Horn Crossover (pt2)
From concept to finished product. This is what my pride and joy looks like. The XO24Pro is a 2-way, 24dB/oct Linkwitz-Riley crossover with interchangeable filter networks. No de-soldering is necessary to change the filters. Simply unplug the daughter board and replace it with the crossover of your choice.
The Crossover Module
The module is simplicity personified. All the resistors and capacitors are of the same values. Four of these cards will cover the most common frequencies used to cross horns to woofer. You can have them from 1.5kHz to 3kHz in 500Hz intervals. The module shown is with a crossover frequency of 1.6kHz. I use this cross point because I will be testing the XO24Pro with the Osprey-12.
XO24Pro with Osprey-12
Fig 1 – 12CX with Low Pass and Selenium D220ti with High Pass
As I mentioned earlier, the XO24Pro is meant for horn speakers. In such speakers, the woofer leads the horn so the delay is in the Low Pass section.
The Blue and Red plots in Fig 1 are with the 1.6kHz crossover module shown above. No passive components are used in the Osprey-12 for these measurements. What is apparent is the steep roll-off in the Selenium D220ti. This is where it beats the passive version.
Fig 2 – Osprey-12 Null
It only took me a few minutes to time-aligned the Selenium D220ti with the 12CX. I am able to align the two drivers better as all it took was a twist of the delay pot whereas in the passive Osprey-12, it is not so simple. Actually, it’s quite time consuming.
Fig 3 – Active Time-Aligned Osprey-12
The final frequency response of the Osprey-12 is in Fig 3. This is with the D220ti wired in reversed phase since the null was with it in-phase. Notice the slight downward slope as the frequency extends to 20kHz. That’s the natural response of the Selenium D220ti. I can make it flat by activating the CDEQ network which resides in the High Pass section of the XO24Pro but for this initial test, it’s not necessary.
Auditioning the XO24Pro
I’ve been listening to the Osprey-12 with the XO24Pro for a few weeks and I’m totally happy with the sound. The XO24Pro is transparent. In other words, I can’t hear the crossover. No veil. And no loss in dynamics. The music flows effortlessly out of the Osprey-12.
February 4, 2022Projects