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
Wondering what type of speaker wires might be recommended for these?
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. 
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Amazing project. You could post pictures by starting an audiogon "system" under your profile. People don't comment much in there, but I still like looking what people have setup... Would be great in your case.
"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."
   Built them in my shop where they remain as they are to big for my house. I run this off of a Dell workstation for source feeding into a Xilica xp3060 then into two Crown xli800's and it is bi-amped for one channel each driver. The crossover point is 500hz. The delay ended up being 6.35ms based on the 88" difference between the woofer and horn driver. Sometime later this week I have someone to walk me through using REW and a UMike to get the right PEQ's to feed into the xilica. Up until, now it has been quesses and fiddling until it sounded good.
" Amazing project. You could post pictures by starting an audiogon "system" under your profile. People don't comment much in there, but I still like looking what people have setup... Would be great in your case. "


  How do I do this? I see the pull down but don't see system anywhere under profile.
" WOW being able to go to the link and SEE the parts, with the drawings. Thank you. it should be wonderful! "
  Thanks and I would have posted the build here except I can't post pictures on this forum as far as I can tell. I have a set of plans available over there on the Klipsch forum for anyone who wishes to have a try at building a set. Better have some helpers or a forklift though as they are big and heavy.
  I can assure you these things produce prodigious super high fidelity output. It is funny to watch people when they hear them for the first time.
  I have yet to use more than around 70 watts per channel as it just gets to loud and starts sailing past 100db quickly. I think one day soon I will roll them to the big rollup door at the end of my shop and point them out and let them rip. I bet they will be audible a quarter mile away. It is just to much in an enclosed space to even think of using the 200 watts per channel. 
OK I figured out how to post systems and it is up.