Building a 27hz single fold horn for a two way horn system.


About two years ago I bought a set of three way Klipsch MCM 1900's. The sound was really remarkable but I wanted the pipe organ to go as low in my shop as they did in real life and the MWM bins while superb did not go low enough. I started tinkering with the idea of building something that would have the same single fold horn construction as the MWM but go much lower.

  During this time frame of developing the idea I was posting on the Klipsch forum and one of the members offered me a set of K-402 horn lenses. I had some 1132 drivers around from some KPT-456's I had and they were the ones Klipsch used for their two way cinema systems. I tried those out on my MWM bass bins and was astounded at the fidelity and decided to go ahead and build a set of speakers using them.
  The traditional MWM bin was either roughly 17" tall for single bins and double that for double bins. The mouth of the horn was 67.5" and tapered to 32" with 44" depth. I wanted to do this with Baltic Birch and since the sheets cam in 60" x60" sheets this was where the design ended up.  The final size was a 60" wide mouth with a 60" depth and tapered to 32" on the back side but the heigth was to be 19.5" so as to use up the most lumber and also dig a bit deeper.
  I don't know how to post the pictures of what was done here and all I see is something where you can link a URL to so that is what I will do. This link will take you to the build thread I have on another forum and page 13 is where I finally start the build.    https://community.klipsch.com/index.php?/topic/177013-super-mwm/page/13/
  This is a bi-amped system using a Xilica xp3060 for time alignment and other settings. I was forced into electronic crossovers and timing and PEQ's because this thing is massive. there is an 88" travel difference between the 402 horn and the woofer cone in the bass bin. The bass bin itself has 106" of travel and the 402 horn has 18" so that is where the 88" comes from and it ends up needing a 6.35ms delay on the horn.

  In any case the sound is astounding once you get everything dialed in for the first time I am next to the big pipes on the organ. There is a physical side to these horns too as you feel them as well as hear them and they don't fool around doing it.
mahlman
Teh new Audioquest speaker wires are the most neutral I've ever heard.  I've heard many of the very expensive wires out there
Very impressive. How did you place them in your room? Do you have pictures of the system? I'm sure they are very efficient and do not require much current. 12 guage twisted pair cord will do just fine. If you are using mono amps keep them as close to the drivers as you can to keep the wires short. 
It is also great that you recognize the delay. It was always one of the problems the K Horn suffered with. The woofer was 4 feet behind the rest of the loudspeaker. Digital cross overs have made full range horns a much more attractive proposition if you have the room for them. Where are you crossing? Have you impulse tested them at all? It would be interesting to see if there was any spurious resonance in the bass horns. If you can find it you can fix it! If I play a 20 Hz test tone through my system the whole house comes alive:) Fortunately the woofers do not but I made these elaborate front grills for them which I finally tossed because there was no way I could keep them quiet. 10 hours of work down the drain. Live and learn.