Lycan3R WP12024 Horn

A couple of months after I blogged about the 3D printed prototype of the WP12024 horn, Trieu sent a pair of these beautifully finished cast aluminum production versions. Included in the package was a set of parts for a horn stand patterned after the Western Electric original I've only seen in Stereo Sound Tube Kingdom.

The cast aluminum WP12024 horns replaced the 3D printed PLA prototypes on top of my Altec Coronado cabinets loaded with Altec 406-8Y 10" woofers. 

Initially, the horns were fitted with Altec 802 drivers + 20275 diaphragms, but I couldn't get a satisfying sonic blend between the horns and the bass bins with a simple 1uf - 2uf PIO cap + L-Pad. There was too much energy and presence in the upper midrange, which was exacerbated by the higher efficiency 802 motor.

Although I can hear certain sonic aspects improved vis a vis the 3D printed PLA prototype, the cast aluminum version was very different such that it wasn't going to be as simple as when I compared the aluminum Altec 32A vs. plastic Altec 32C. In this particular horn design, the material used had a more significant impact on the sound!

Altec 406-8Y + WP12024 + 806/GPA 34852 
+
JEL N1600C XO

Consequently, I replaced the Altec 802s with a pair of 806 drivers with GPA 34852 diaphragms in conjunction with my N1600C crossover. Only then did I realize that the 2-3 dB difference in efficiency between the 806 and 802 wasn't as apparent with the 3D printed prototype. The sound was better but not quite good enough because IME, the 10" 406-8Y, 406Z and even the 12" 414A/Z, low frequency drivers lose snap when rolled off by a crossover.

Meanwhile, Tish and I had to pack for a long overdue visit to the Philippines.

Fresh new ideas were brought forth by our delightful vacation. While nursing jet lag, I listened only to the WP12024 horn/806 driver combination at a couple of different crossover points with and without top end EQ. Aided by my iPhone RTA app + more listening tests with the Coronado bass bins, I eventually arrived at the above crossover. 

Altec 406-8Y + WP12024 + 806/GPA 34852
12dB XO @ ~ 4.5 kHz, no HF EQ

I dispensed with the high frequency boosting EQ, shifted the crossover point over an octave higher, and employed a 12dB/octave filter while letting the 406-8Ys roll off mechanically. 

With this set up I got closer to the ideal blend and tonal balance in my mind's ear. The sandcast WP12024 sounds more vivid in the midrange with greater top end extension and shimmer compared to the 3D printed PLA version.

Since the Western Electric KS12024 horn was originally paired with the phenolic diaphragmed WE713B driver, I mounted my pair of Altec 808 drivers with Symbiotik diaphragms on the WP12024 horns. Not quite a direct modern equivalent but close. Despite not making any adjustments to the crossover network, this combination sounded very lucid especially with vocals!

It was an opportune moment to continue my experiments in the main listening area. This way, I could sit farther away from the speakers and use wider bandwidth amplifiers + a whole new set of ancillary components to widen my perspective.

I pulled out my favorite Altec 414Z woofers in repurposed Madrid cabinets and replaced the 806 drivers with GPA 34852s with 802 drivers with 20275 diaphragms. The crossover is hinged @ about 2500 Hz.

Altec 414Z + WP12024 + 802/20275

Comparing this set up to my Altec 753C is a moot point because it's based on the Western Electric 753C, which was designed as a studio monitor, whereas the lineage traced by the WP12024 horn was in the Westrex L8 speaker system and intended for a small(ish) theater or auditorium.

The WP12024 horns + 802/20275s + larger 414Zs in Madrid bass bins reminded me of my GIP Labs Monitor 1 experience in Manila - mid to front row presentation, vibrant and scintillating!

In the above video, the Altec 802/20275s were replaced by 808 drivers with Symbiotik diaphragms and instead of L-Pads, I installed Intact Audio speaker autoformer attenuators. 

To be continued...😉 

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