Wednesday, November 29, 2017

New Three Way Horn System In The Works

I've been collecting parts for this for many years. This may be the slowest project I've ever done. My friend JC designed the basshorn, provided the math for the builder of the tractrix mid and tweeter. I need to build top hats for these and my least favorite part the passive crossover. Fortunately my friend Chris is helping me with this or I'd have to go active. 

Here we have the bass horn. It is large and can accomodate 12" 15" or 18" drivers. For this application we are using 12" drivers. These will play up to around 350hz.
I am a toddler when it comes to putting systems together but the main point in DIY is to learn so if it doesn't work try and try again.
I need more stuffing. 

 Fortunately these drivers can pick up around 350hz. These are JB 2482 drivers and are so very heavy.
 They will be mounted to these pure tractrix horns. They do look better in person not sure what the flash did here.

 Most of these horns are on loan to me but will be fun to try out for a while. Round tractrix with B&C DE250. They start breaking up past where I can hear lol....
This will be going together soon and then tweaked until it sounds right. That will likely take a while. This will be my second system on the other end of the house lol. Now to find technology to stream audio in sync to both systems... Anyone have any suggestions?

Check out the DIY tractrix horns at Fastlane Audio.


  1. If you can find one, the Audio Alchemy DST may allow you to extend an SP/DIF signal from one room to the other. Running the cable would be the hard part...


  2. Hi Iain, Depends on what you want to send, Analogue, Digital or streaming services?
    I ended up having to use Sonos which whilst not ideal is handy and taps into all my streaming services especially BandCamp as they allow purchase of the vinyl AND uncompressed DL and streaming.

    If analogue then Id run shielded XLR cable and use some kind of balanced system either active or passive so that you keep noise to an absolute minimum.

    Digital would be hardest as youd either then have to only listen to digital signals or use an A>D and D<A pair which as Im sure youd know/guess is a whole nother ballgame!!

    Good luck and let us know what you end up with...


    1. I even considered low power FM lol..... Thanks for the input.

    2. Hi Ian- Great project! I love the FM idea. Here is a beautiful transmitter:
      Totally love the sound of good FM. To me it is transformational. Like great tubes.
      The 2482 has a strong rise around 800Hz or so. In a horn like yours, I’ve ended up
      with a shockingly small cap. Losing some low end, but pure first order, one cap, that’s it.
      Very best to you, Mats

    3. Thanks for the transmitter link. Very nice. I do like the idea of broadcasting thin the hood 8-) and to my back yard.

      We are going to do a simple first order starting and will see how it measures might just need something around 800 but we will see. I'll look for it now. Thanks for the feedback.

  3. Those JDL drivers are soooo heavy. Installed a pair on a "Y" manifold for a single long throw. Hauled the assembly up scaffolding and hung from a very high ceiling in an aircraft hangar. My helper/friend and I both worked for the fellow who thought this up. My friend said afterward that it was awfully heavy but probably for the best considering the extra output. I explained to him that the assembly only added three decibels to the acoustic output. He was furious. Anxious to hear your reports from testing.

    1. I would not have wanted to be that high up with such a rig....

      I'm testing crossovers for the next month or so. I hate crossovers lol....

  4. Hey Iain, good to see you making use of those bass bins. Have you considered swapping the bins so that their mouths are on the side walls, and rotating them for a smooth transition out of the horn mouths? This will give you a bit more LF extension and eliminate a mid-bass frequency notch due to 1/2 wave bounce (otherwise called the "Allison effect"). Putting something fuzzy on the side wall exits next to the bass bins will also control "midrange broadening" in the horizontal axis. A couple of 2'x2' squares will work wonders, as well as something on the floor to help damp floor bounce.

    As far as getting the passives set up, have you considered using an active to dial in the EQ and delays, then transferring the active EQ settings to a passive network using something like XSim in order to eliminate the cut-and-try approach to flattening the frequency response? JMTC.

    Chris A

  5. Actually yes I was going to swap the bins 8-)

    Fortunately we have enough parts to wing the passives. The horns are pretty much telling us what to do except for tweeter which gets rolled off early. We are doing thngs simple old school Klipsch style. Once dialed in I'll get some quality parts. If I ever decide to multi amp I'll do a line level passive. Not expecting perfection to start but rather just a start..

    Hope all is well.

  6. Nice.

    This can will fit 12 and 15 woofers. Not 18.

    I would keep the cabinets as you have them just sneak them a little more in the corner by toeing in. In that size room, the throw of those cabinets will be better with the exit/mouth on the back wall....not the side wall.

    The 12" woofers Klipsch K31 I used went out to 400Hz. The B&C 15PS100 barely got out to 400Hz. The B&C 15BG100 didn't do well pass 300Hz but they would literally pound your face. It was kinda scary really as it would give you a gut feeling that you couldn't tolerate that long. Those drivers definitely do better as subs.

    1. I remembered orientation of horn mouth wrong. This is good as it means I don't have to swap them lol.

      I guess I pulled 18 out of my ass. LOL... Would be scared of that if they did fit.

      I'll stick with K31. How low did the B&C go? I love B&C drivers.

      I got the stands for the 2482s built and everything attached to the horns. Hopefully a listen test this weekend. Then we will build some K style tophats.

      This is gonna be cool.

      Thanks again for all the help JC.

  7. Careful with that Ashly (don't let it fall). Those are hard to find in good condition on the used market.

    I use the 2 way and the 4 way units all the time for quick setups.