Sunday, December 17, 2023

3D printed WP12024 horn from Lycan R&R

In late September, I received a message from Trieu of Lycan R&R, asking if I'd be interested in evaluating his 3D-printed prototype pair of multi-cell horns.

Before proceeding further, this blog entry contains a lot of hyperlinked texts to either previous entries or other sites pertinent to the article (e.g. "Lycan R&R" above). Mousing over and clicking those texts will open the link on another page. Thanks!

Design notes from Trieu: "These horns are slightly wider. The original KS12024 has a rather narrow 50° horizontal dispersion. When updated to the 1" driver opening, the wider initial diameter of the of the 1" driver would not allow for the throat geometries to work correctly. I felt the slim vertical profile of the original KS12024 is important sonically.

The best way to maintain it is to increase the horizontal width via a wider angle. So I increased the horizontal dispersion to 62.5° allowing for the proper expansion and geometries of the throat piece. BTW, I used carbon fiber infused PLA filaments."

Westrex L9 = 2 x WE754A woofers + 2 x KS12024 horn
+ 2 x WE713B drivers

For the record, I never heard an original Western Electric KS12024 horn nor its companion phenolic diaphragmed WE713B compression driver. However, for a complete technical and historical background of this horn and driver combination, Joe Roberts discussed them in the context of the late 40s Westrex L8 and L9 cinema speaker systems from the collection of Silbatone Acoustics + more on HiFi Haven.

Westrex L8 = WE754A + KS12024 horn + WE713B driver
from the Silbatone Acoustics Collection

He also shared his thoughts on the WE KS12024 vs. Azzolina KS12024 + others. Please note that in his HFH post #125, J-Rob was actually referring to the KS12024 while inadvertently typing "KS12025."😉 Incidentally, the KS12025 was the only straight horn contemporaneous with the bent 32A, KS12024 and KS12027.

Altec 414Zs in Coronado cabinets + Azzolina KS12024 horns + 802 drivers

I eventually became the long-term beneficiary of the Azzolina KS12024 loaners. I've been enjoying them with Altec 806+GPA34852 or 802+20275 compression driver/diaphragm combos sited on top of either Altec Coronado or Madrid bass bins loaded with 406-8Ys and 414As, respectively. These are my alternate speakers to the Altec 755As or 755Cs in Silbatone cabinets on the other side of the man cave where I do most of my goofing and testing.😊

Given J-Rob's proximity, he can knock on my door any time to retrieve the Azzolina horns.😉 So Trieu's sample test offer was hard to resist. Upon receiving the WP12024s, I mounted them in place of the Azzolinas. In the meantime, I played mostly background tunes from my FM tuner and Raspberry Pi streamer + nosTDA1541tube DAC because I was busy entertaining my brother who was visiting.

After he flew back to Manila, I started listening intently. I went through my LP and CD collection and experimented with various combinations of flea-powered triode amps from my stash - SE 71A, 46, 45, Radiotron 2A3 or CCC 2A3 paired with either the RCA 5691 phono + nickel plate choke loaded 76 preamp or my recent DIY 6SJ7/6SL7/6SN7 passive RIAA EQ phono preamp + Intact Audio nickel AVC.

I used a couple of crossovers to hear how the horn behaves at different crossover points from around 1200 Hz and up. IME, given the size of this horn, I would not venture lower than that especially with gentler crossover slopes, which I prefer sonically.

Altec Coronado/406-8Y + WP12024/806A

Since the WE/Altec 32 horn isn't ideal for top of a bass bin mounting due to its asymmetrical vertical dispersion, the Emilar EH500 and EH800 were fine alternatives for a top mount situation. Unfortunately, not too many Emilar horns were manufactured, thus, prices have also gone through the roof. Besides, I prefer the Azzolina KS12024's tone in spite of the narrower horizontal dispersion.

To cut to the chase, I couldn't detect any tonal difference between the WP12024s and Azzolina KS12024s. It’s as if I never changed horns, which is a great achievement in and of itself. Regular blog readers know that I personally prefer a mid to back hall perspective, which is how my Altec 2-way project evolved to the Altec 753C with a 32C horn. However, for a front row/near-field presentation, the Azzolina was at the top of my list. Now the WP12024 has taken its place!

Please click here to read my Azzolina KS12024 horn review, because everything I love about it is preserved in Trieu’s reconfigured version. The most significant improvement is in the wider horizontal dispersion + a bit more shimmer in the extreme top end!

If Trieu decides to manufacture the WP12024 and all the sonic attributes of this 3D printed sample is transferred to the sand cast production version, it's a clear winner in my book!👍

J-Rob's WP12027

As an aside, before handing them over to John Piro who was commissioned to construct a pair of his WE757A clone cabinets, I also got a chance to listen to J-Rob's pair of WP12027s. These are Lycan R&R's sand cast horns inspired by the WE KS12027 and recomputed for Altec 1" compression drivers.

Click here for my thoughts regarding the KS12027. I also talked about it in the context of John Piro's WE757A remake. To my ears, Lycan's WP12027 horns are a must for those fortunate few who own WE728Bs (so far I haven't been, that lucky 😔), but can't find and/or can’t afford a pair of original KS12027s + WE713Cs.

For more info about these horns, visit Trieu's Lycan R&R forum on HiFi Haven or go to the Lycan 3R group on Facebook.