2-way horn system based on the mk3b2

Just iterating over crossover versions. Current crossover in the system
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Here is a non-optimized passive crossover version (I know it is a lot of parts :D)
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It will be interesting to listen for the dynamic performance of this speaker. IME too much equalization to the order of +/- 1dB robs music of its dynamics and risk sounding too sterile and boring. YMMV.

Soulmate chief engineer calls this static or catalogue performance vs dynamic performance and gives it a name - curse of Fourier. I concur.
 
@Hari Iyer: IME, equalization is fine as long as a driver/speaker can take it. Dynamic compression doesn't much raise its head.
Often, good pro audio drivers respond well to EQ, whereas many drivers marketed as 'hifi' don't. Such things need to be decided on a case-by-case basis. So yes, It needs to be decided and seen/heard how this particular system responds to EQ.
 
Just tiny bit of component cut down while not compromising much on the power response, PIR and early reflections curve, while also trying to flatten out the impedance of the system above 100Hz.

The CD+horn response is rowdy here. It just eats up crossover components :D
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Some questions,
As woofer impedance rise rapidly after 300Hz using a Zobel network will prevent crossover frequency from shifting.
Why DCR of inductor is increased with a series resistance? This will affect transient response imo.
Similarly adding a resistor in series to capacitor four LP filter will affect transient response. You can consider modifying crossover frequency slightly for getting the target FR.

My 2 paise.
 
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Some questions,
As woofer impedance rise rapidly after 300Hz using a Zobel network will prevent crossover frequency from shifting.
Why DCR of inductor is increased with a series resistance? This will affect transient response imo.
Similarly adding a resistor in series to capacitor four LP filter will affect transient response. You can consider modifying crossover frequency slightly for getting the target FR.

My 2 paise.
Questions or opinion? The latter is not taboo on this forum. We don't mind flexing if the person knows their scheissè
 
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The Hells Bells

We (mostly @Vineethkumar01) have worked serious magic on our horns, the Hells Bells. After tinkering with several active crossover points, EQ tweaks, and speaker positioning/placements, we've finally found the sweet spot!
The Hells Bells are a little picky about where they live. We had to wheel them around, push, pull, and twist them until they decided to make friends with the room. Thank goodness for those wheels, seriously! Now they're sitting pretty at a 20-degree toe-in and with 8 feet between them.

Ever heard a horn that sounds like a hi-fi speaker? The Hells Bells combines the clean directivity and dynamics of a horn with the smoothness of hi-fi. This bass horn undoubtedly stands out as one of the most refined and effortless bass experiences I've ever encountered. It fills the air with a warm glow that invites Leonard Cohen to dig deeper, and plenty of slam power on reserve for low-digging electronic music.
The marriage of the mk3b2 and the 15PR400 bass horn is indeed a match made in heaven. The cohesion of the tone is seamless.

The common inhibition that horns sound, well, honky/shouty is due to bad design, first, and selection of CD, next. It's a complex science (let's be honest, whatever I do not understand is complex science) to get the horn geometry right, and we are grateful that there are still a few wizards willing to share their work with the DIY community.

This project, having roots in early June, was a plunge into unknown waters. Vineeth backed by his strong technical prowess, and I, backed by my strong imbecility, decided it was worth considering and poured all our heart and soul into it.
Even before Vineeth started reading me my rights on the perils of an untested design, I said YES!
It was only the next morning did I realise that it was the Old Monk that spoketh on my behalf. One foot already off the boat, we thought, might as well dive in and swim the depths.

To obtain a first-hand understanding of the horn's performance, we printed a 3D prototype. The process wasn't as smooth as we hoped, thanks to some software compatibility issues, but Vineeth helped iron out these kinks to make the 3D files usable.
The horn was an ordeal to fabricate and glue the various sections to align seamlessly, but accomplished; partly thanks to my ingenious fabricator, who turned out to be a master of jugaad!

We were also keen on 180-degree measurements for the radial fin horn, not only for our benefit but also for the sake of posterity, as such a horn had never been thoroughly measured before. Polar measurements give us a visual indicator of dispersion/radiation behaviour to help us understand the characteristics of a speaker.
I lugged the horn back home from the workshop and plonked it on a 15" subwoofer (that was also a collaborative effort with Vineeth) to get a "feel" of the horn.
Subjectively, I quite liked what I heard, and Vineeth liked the look of the polars, the MK3B2 showed promise!

Then came the CD adapter saga. Turns out the CD we chose had a bit too wide an exit angle for our horn. We needed one with an exit angle of 10 degrees or less. This meant that the CD extension in the upper region would be limited. Vineeth redesigned the adaptor and a ring insert to narrow the exit angle, and to push the upper extension of the CD further, which we tested here in Post #46, and Post #47. This success pushed the boundaries of what a biradial horn was previously thought capable of. delighted and gleeful we were.

We still weren't sure how the final system would sound, and if the final result would be to our liking. We discussed a few options, including a system with ATH STA260 waveguide. But, any untested change we make would still be an unknown. As we had already tested and familiarised with the mk3b2, we thought it held enough merit and was worth pursuing.

Three months of sweaty foreheads, smelly armpits, dusty shirts, bruised and sticky fingers, and we are finally home. Priceless, rewarding experience!
There is indeed magic in a properly designed 2-way 15" horn-based system, something to be experienced first-hand, not read. Also, probably the only Hi-End horn system in the world strung to Finolex and Spotify ;)

@Vineethkumar01 has been a rock, always reasoning and articulating every step of the way to ensure maximum success. I cannot thank him enough! It's gut-wrenching that he isn't here to experience his creation. Some of you from Bangalore along with Vineeth should hop into a car and drive down 🚗💨. Seafood, toddy and AC/DC sound good?

P.S. When my playlist automatically resumed after connecting, AC/DC's "Hells Bells" thundered down these speakers. This was the very first track I heard, and man, it sounded enormous! I mean, it was fate to name them that, right? 🎸🔔😄
 
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@Vineethkumar01 has been a rock, always reasoning and articulating every step of the way to ensure maximum success. I cannot thank him enough! It's gut-wrenching that he isn't here to experience his creation. Some of you from Bangalore along with Vineeth should hop into a car and drive down 🚗💨. Seafood, toddy and AC/DC sound good?

P.S. When my playlist automatically resumed after connecting, AC/DC's "Hells Bells" thundered down these speakers. This was the very first track I heard, and man, it sounded enormous! I mean, it was fate to name them that, right? 🎸🔔😄
Your journey has been fabulous and the speakers look great. I'm going to take up on that offer some day and be the fly on the wall. Will you be removing the wheels later? I ask because folks talk so much about spikes, no spikes, coin beneath the spikes and suspension systems costing more than many speakers, I was wondering if putting wheels is akin to blasphemy :p. But my guess is that it doesn't matter because the weight of the speakers by itself gives them a rock solid foundation.
 
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@aeroash: Really happy to hear that you like the speakers. :)
Hopefully, I will get a chance to visit your place and hear the speakers in person :)
I really admire the passion & the hard work you have put into this project.
Nobody I know (in India) has done proper polar measurements for a speaker (especially this big) to the extent you have done in this project.
I just hope this project inspires many more DIY people to take up similar projects and push the boundaries of DIYing forwards :)
 
@Hari Iyer: Thanks for the suggestions. Right now the passive crossover design is in a stage of crossover component cut down iteration.
In earlier passive crossover versions, my approach was to get the transfer functions correct & the overall set of frequency response curves correct and not worry about which component goes where. It was mostly just a transfer function replication exercise.
Now is the stage where we have started focussing on component optimization, penny-pinching and trying to see if we can do all this without much damage to the system frequency response curves.
Here is the latest version of the crossover (which is still undergoing iterations).
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Reverse null test
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With some PEQ along with the passive crossover
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By the way, the DC resistance of inductors seen in the above pics are populated by default in VituixCad. I have not altered it yet..
 
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Your journey has been fabulous and the speakers look great. I'm going to take up on that offer some day and be the fly on the wall. Will you be removing the wheels later? I ask because folks talk so much about spikes, no spikes, coin beneath the spikes and suspension systems costing more than many speakers, I was wondering if putting wheels is akin to blasphemy :p. But my guess is that it doesn't matter because the weight of the speakers by itself gives them a rock solid foundation.
Thanks, @mbhangui You are more than welcome :) There is also the Tarkus to experience, which I believe is a phenomenal 3-way.

I have never been a fan of the spikes, in fact, I used rubber feet on the Tarkus. This is also partly because the enclosures have solid bracing to keep the vibrations to a minimum. The soft rubber feet absorb the rest.

This bass horn is made with 25mm walls, and the baffle itself is 50mm. Added to this the fins of the horn attached to the baffle also further reinforce to make an extremely stiff face for the driver. The driver barely moves when pushed to ear-splitting volumes, and the cab itself barely has any vibration when the bass drops. The wheels are more of a boon/convenience and I find no reason to remove them. The popular understanding is that the bass is reinforced when the cab is nicely planted on the floor. In my case, I have to dial down the bass.

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In my H-frame I am using 3 nbrs ,12mm SS hexnut below my box as feet for a strong coupling.
 
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