Asathor - a JBL 4367 Clone


Hi Guys!

I have always been fascinated by the large monitor speakers from JBL. Unfortunately, these are not cheap, so I wanted to build something like the 4367 myself. JBL (1)/JBL Synthesis 4367 White Paper.pdf

15 "plus compression driver / horn was given. So I started looking for suitable drivers.
My friend Nico Germanos from Quint-Audio, Germany gave me the tip to test the new Tymphany DFM drivers and sent me a pair.
Since I don't have many horns to test, I immediately sent the drivers to my DAU buddy Christian. A few days later he sent me the measurements on the Monacor MRH-200 and I was amazed. Nico was right, the Tymphany DFM-2535s run great.


Since the MRH-200 is quite expensive, I decided on the almost identical Celestion H1 9040-P, which costs only a third.

Now I had to find a suitable candidate for the bass. Since the DFM is quite cheap despite its great measurements, I wanted to stay in a similar price range in the bass as well. Together with my friends from the DAU we discussed many possible woofers, but most of the cheap ones needed too much volume for bass reflex. In the end it was the LaVoce WSF152.50, which was kindly made available to me by the German distributor Steinigke Showtechnik.
This woofer runs very well in a closed box, which is brought to a lower cut-off frequency by a high-pass cap. Not super deep, but it will work well when the speakers placed close to the walls.


Both drivers are very well made for this price range. Since the Tymphany and the horn are smaller compared to the drivers in the JBL 4367, the crossover frequency is higher than in the original. I ended up at around 1500Hz.


The box also works very well at 15, 30 and 45 degrees horizontally off-axis (2db offset).


The crossover is an 18db high pass and a 12dB low pass plus serial notch.


The cost in Europe is less than 500 Euro for a complete pair. Certainly not much for a loudspeaker that has a surprisingly good sound and can also manage very high levels without problems.

If you want to see more designs from our small diy-group, please visit our german homepage:
Presenting DIY-HiFi Projects - The Idea behind It! - Der-Akustische-Untergrund

:cheers: :wave:
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Well, your images didn't post. Please try again & no external links.
You have to go advanced to link to images on your PC or external images.
There are few 15"+horn builds on here. I've respected the format since my band director suggested we go listen to the Altec Lansing Voice of the Theater speakers at a cinema in 1966. Those were never even for sale within 200 miles of Houston, much less affordable.
Everybody on diyaudio seems obsessed with getting 100 to 20000 hz with a 5" and a 3" driver in a gorgeous enclosure. Which drivers are so much alike I don't see the point. Strumma strumma guitar & voice. I'm a piano player, and like to listen to full frequency recordings when I'm eating or reading and not playing. I've found dual 10" plus 3 mallory piezo tweeter speaker, Peavey 1210 okay. I've found 2" horn + 15" woofer really good in the SP2-XT . +-3 db 54-17 khz. The burglar was so happy with them he carried them off.
So I'm looking to build some similar speakers ugly enough they have no resale value. 2" RX22 horns are cheap on US internet markets, I bought 2 for $130. But woofers you have to buy new. I'm looking at Eminence delta-pro15A that don't have metal frame losses or dips below 3 khz. And I don't know what was in the SP2 crossover, only that is was 12 db/octave @ 1200 hz. 1200 hz would get rid of beaming or edge diffraction of higher frequencies on a 15" driver. Everybody else is using 1" horns and 2000 or 3000 hz crossover. I don't need 14000-17000 hz, I can't hear it.
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Images are still not loading for me, sorry to say.

I'm intrigued with the 15" + horn format myself. I have a set of DIY Sound Group Fusion 12 Tempests and they sound quite good, especially for home theater use. I'm also intrgiued by the likes of the Klipschorn, La Scala and Belle loudspeakers and would love to put together a design with a lot of live music presence.

Subscribed. :)
Ok, I'll try it again. Strange that I can see it all. :angel:

Tymphany DFM2535 with Celestion Horn:
Bass simu:
Measurement on axis:
Measurement off axis (0, 15, 30 and 45 degrees, 2db offset):

Hope, it will work :cheers:


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Very nice overall and off axis response. I walk around while listening, so off axis it important to me.
Looks like bass is only 5 db down @ 40 hz. That is better than SP2-XT or even Peavey 118 18" woofer. Is that because your bass cabinet is so big? Looks sealed?
Thanks for showing crossover. RM22 horn calculates to 51 uH series 4.7 ohm.
For 1200 hz 12 db crossover I came up with 1 ohm (tungsten power limiter) series 22 uf with .22 mH parallel the horn.
Eminence DeltaPro15a speced @ 5.7 ohm series .83 mH. I put 5 mh series & 2.2 uf parallel. First model using browser sim. Puts .67 v on each driver @ 1200 hz with 2.83 v drive.
Your crossover looks cheaper. 5 mh & .22 mh are $$.
I can't use any windows simulator unless I make a huge donation to the defense of a foreign country. One that buying eminence driver avoids.
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Off axis respons is not only important when you are outside the sweet spot. At the listening position, significantly more sound energy comes to the ear via reflections than directly from the loudspeaker. That is why this is also very important on axis.
In my experience you get a very good illusion of the sound when there is a good response off axis.
Yes, at 40Hz this is about -5dB. It's a closed cabinet with around 90 liters (around 2.16 square feet) and a big cap to push low frequencies a little.
Here you can see the difference between closed box (red) and closed box with high pass (black; in Germany it's called GHP). Both with same volume.


Crossover is pretty easy. Only the baffle step correction requires larger components. But cheap coils and simple caps are sufficient here.

I forgot the impedance measurement above:


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Looks great except for the 3.6 ohm minimum @ 120 hz. If I'm going to play organ music @ 70 w with my house amp, 2 pairs 2n5630 2n6030 output transistors, I'd have to leave the parallel caps out.
If speed of sound is 880 ft/sec, then divide by 54 hz, 16.3 ft, half wave is 8.1 ft. Wondering if I could curl up a plastic 3" drain pipe that long in a box as tall as yours to make a port to boost lowest octave. My speaker is 1.5-2' from a hard plaster wall, so the port on the back for bass only should not be too annoying.
Unfortunately eminence Deltapro15a doesn't work for vented box. Have to use kappapro15.
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A handsome speaker.

I wonder if the bunching up/diffraction between 2-3k is inherent to the horn or the CD/horn combination? I use the same Peerless driver and I agree it is great.

Thank you!
The horn plays a little wider than the bass between 1.5 and 2.5 kHz. Especially at small angles. Here is a measurement with a Sica driver. The same behavior can also be seen there, so it's up to the horn:


Thanks! Yes, the Celestion H1 9040-P/Monacor MRH-200 are oldies, but goldies. For the price, the Celestion is a real bargain.

thank you too

Many people think of the typical PA party speakers when they see them. But the Asathor plays more like a good hi-fi speaker. I actually wanted to make a version with a higher quality woofer, but the LaVoce plays excellently in the midrange and goes very deep in the bass if necessary.
The driver horn combination does everything right in my ears.
Whether Eric Clapton or Billie Eilish, when you close your eyes it seems like the artist is standing in front of you. The speakers themselves disappear completely.
And that works even at very high sound levels.

I listen to a lot of rock and metal, which unfortunately is often poorly produced. It can get a little too much at high sound pressure levels. That's why I made a small modification for myself and connected the tweeter with a smaller capacitor (4.7 instead of 6.8). As a result, there is a small dip at 2kHz, which makes this music much more pleasant.


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Fabulous project Rese66!

Well Done!

Also, thankyou very much for all the meaningful curves and data. :)


PS; maybe you could have a moderator revisit // reword the title to something a bit more searchable.
- Was the word "Asathor" supposed to be "Another" or is it maybe some obscure reference to Odin's son? :confused:
Thank you EarlK!

"Asathor" is another name for the thunder god Thor. Since he belongs to the family Æsir, he is also called Asa-Thor or Asathor in some scriptures.

There is a song by the Swedish death metal band "Amon Amarth" which is also called Asathor. I heard this song in a club many years ago and it never got out of my head until I discovered it by accident about three years ago. So I thought it would be a good idea to name the speaker like this song. It was also the first song that ran over the finished Asathor.
Amon Amarth - Asator - YouTube

You're right, I should come up with a better title for this thread.