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folded horns

Discussion in 'Amps and Cabs [BG]' started by Mikeels, Jul 1, 2001.


  1. Mikeels

    Mikeels

    Apr 20, 2000
    So.CA.
    Has anyone tried using a folded horn for the bottom end.
    I would like to build a 15" folded horn cab if someone knows where I could get plans!
     
  2. mchildree

    mchildree Supporting Member

    Sep 4, 2000
    AL/GA
    There's a pretty widely-circulated set of plans that EV (ElectroVoice) distributed for a 15" folded-horn enclosure. I have them, they look fairly easy to build if you have the correct woodworking tools like a table saw, mitre saw, etc.

    I've seen players use these for bass bottoms...lately, Ashdown is making them. I just saw Entwistle's rig for sale at BassNW, and it had one. I can say from experience, though, that unless you are playing LOUD and on a BIG stage, it may not be the best choice. That design is a super-long throw and your lows may develop way out into the crowd instead of where you want. I have a pair that I use with my PA rig, but end up opting for my front-loaded 18" more often than not.
     
  3. JohnP

    JohnP

    Jun 9, 2001
    Chicago
    Endorsing Artist: Rick Turner Guitars, DTAR, Seymour Duncan,
    Mike-
    those 145 lb ashdown 1x15 cabs are the old ev design?
    when you built one, did it weigh this much? it doesn't look that large to me from the pics. is this their old Eliminator cab?
    jp
     
  4. mchildree

    mchildree Supporting Member

    Sep 4, 2000
    AL/GA
    I never built the cabs from the plans...but I do know someone who did and they're pretty big. The plans are they old Eliminator design. You're right, the Ashdown cabs look quite a bit smaller.

    As far as weight goes...I don't think the EVs would weigh quite 145lbs, but they're not far from it. The plans call for 3/4" marine-grade plywood all around. Throw in a 400-watt EV Proline 15" or a nice JBL driver and I imagine you'd be in the same neighborhood.
     
  5. mchildree

    mchildree Supporting Member

    Sep 4, 2000
    AL/GA
    Where Ya been, JP? Haven't seen you around in a while (or have I just missed it?).
     
  6. A folded horn has to have a column length of 27 feet and a 12 square foot mouth to properly reproduce low E, and more than 36 feet for a low B. Shorter lengths are a compromise and push the lowest reproducible note higher up the scale.

    You can't stuff Dolly Parton into a "B". :D

    Building the horn flare is difficult to accurately reproduce in a straight horn, and an order of magnitude more difficult in a folded configuration. If you screw up the flare, the horn is mostly useless.
     
  7. MikeyD

    MikeyD

    Sep 9, 2000
    If the Acoustic 301 or Fender 18" folded horn designs couldn't produce low E convincingly, no one in his/her right mind would have ever bought one (they are too big to haul around otherwise). I have played on the latter, and you could almost kill people playing low E through it. Rickbass1, can I get a witness? Rick had a rig with 3 of them, as I recall.
    - Mike
     
  8. Chasarms

    Chasarms Casual Observer

    May 24, 2001
    Bettendorf, IA USA
    The guitar player in my band has an acoustic 301 cabinet. It sounds decent from about 30 feet or more away. If you are any closer than that, you can't hardly hear it.
     
  9. I used a folded 15 and 18 back in the late 70's and early 80's. You know back when I had looooong hair and bigger was better. Now they are in my practice room with junk sitting on them. They are definately LOUD (and heavy) but you need to be 50 feet away from them to really hear what they will do. If you do build one make sure you install solid cut in handles on it. My 15 has bolt on handles and I had to put drum sticks in them to keep them from vibrating. Even the vibrating handles were loud on that cabinet.
     
  10. MikeyD

    MikeyD

    Sep 9, 2000
    :D LOL! Dave Barry should pick up on this: "JB and the Vibrating Handles" would be a good name for a rock band!

    Anyway, another thought about folded horns - the old '70s movie, "Earthquake" used Cerwin-Vega (I think) folded horn cabinets, and the idea was to put enough really low bass into the theater that you'd think the ground was shaking. That they could do pretty well. These were cabinets that were on the order of 2'x2'x4', as I recall. If you go to C-V's web site (http://www.cerwinvega.com/products/professional/sl36b.html), you'll see a newer variation on the theme.
    - Mike
     
  11. Bgavin, please don't forget that the floor and walls in a room contribute to the mouth area positively. Even an elevated stage could be considered a widening "pathway". They're not ideal horn demensions, but I'm sure a folded horn at the beginning of a "room horn" can produce down to low E, with the right placement of the cab.

    I think a folded horn is pretty useless as a stage monitor, because of the throw issue. Especially the midbass, the part you need most to hear yourself, is thrown out 10-20 feet away from the cab. It goes right past you.
     
  12. JohnP

    JohnP

    Jun 9, 2001
    Chicago
    Endorsing Artist: Rick Turner Guitars, DTAR, Seymour Duncan,
    mike,

    i used 2 cv cabs in 78- but they were not earthquakes..something else..a folded horn with a 15. very low-mid thuddy sounding (or was that me? both!) I wish I could find one of those now..though back then I didn't carry or set up my gear.

    I used 2 Galien Krug cabs after that..4 12's in a folded horn, with a box in the middle with 2x10- 2 of those were really nice. liked them better than the svt's. again though, never had to move them..they were in flite cases too!

    creeeeeek,
    jp
     
  13. I've done 30 years' research on horns, and I don't forget that half-space and quarter-space radiation contribute to reinforcement. The Klipschorn is closely coupled with the walls of the environment, allowing it a mouth much smaller and a shorter air column than normally required for low frequencies because it uses the room as the extensions. However, the horn mentioned above is not a Klipschorn, but a free standing unit.

    Horn radiation is a function of mouth diameter and air column length, and there is no such thing as a free lunch. The bare minimum air column required before a wave can partially couple is a half wavelength. Doing the math, this is nearly 14 feet for a low E. Using 1/3 wavelength as the minimum mouth diameter, one still has to have 63 square feet minimum. A horn with these minimum specs would be a poor performer at low E, and these specs are a lot bigger than the horn in discussion.

    Joris, I am on the sidelines because IMO this is a faith and testimonials discussion. Yes there is a loudness or long-throw benefit in the upper registers, and the horn in question probably reproduces low E "convincingly". But this is very different from "accurately."
     
  14. Bob Gollihur

    Bob Gollihur GollihurMusic.com

    Mar 22, 2000
    New Joisey Shore
    Big Cheese Emeritus: Gollihur Music
    I built a pair of folded horn cabinets loaded with JBL 18" drivers in the mid-70's and played them stacked, with the ports in the middle (top one "upside down"). It made a meek little "meep-meep" sort of sound on stage, but 20 feet away it was like somebody was throwing bricks at your chest. I biamped them with a Fender 2x12 cabinet - wrote an article on it that was published in a 1980 or '81 Guitar Player magazine issue. They were brutal to carry (3/4" ply all around) but sure filled out the rock trio I played with back then.

    However, with today's cabinet designs and more sophisticated drivers, the only place I'd use something like that would be anchoring the bottom octave or two of the PA.
     
  15. That was you. Sorry, I forgot. You must have mentioned it.
    Agreed.

    And when it comes to horns, I should probably... well... say nothing.
     
  16. Mikeels

    Mikeels

    Apr 20, 2000
    So.CA.
    Really, what got me thinking about em was a classic rock cover band that plays at the racetrack just about every Sat. You can hear this deep clean bass all over the track and they are using "three" of the Cerwin Vega folded 18s. Youv'e no doubt seen my posts about the acme cab not being loud enough. I just thought if I used one of these I would be plenty loud but still tight. We started playing this room that is really huge....at least 40' dp x 80' wide. They have a sound guy who either doesn't like the bass....or can't mix, and I get lost in the mess. Now that I know about the sound going past the player though, this would not be a good option for me.
     
  17. MikeyD

    MikeyD

    Sep 9, 2000
    I've also heard some great-sounding systems based on folded horn subs. As others have pointed out, the development of the sound from them doesn't really happen well on stage. Check out my thread on throw of loudspeakers (http://www.talkbass.com/forum/showthread.php?threadid=9774). For larger or outdoor venues, maybe having a front-loaded cabinet with 10's and perhaps a 15 would be great for near-field (on-stage) sound and then a folded horn for projection to the audience (if the PA can't reinforce the bass adequately) would be ideal.
    - Mike
     
  18. pedro

    pedro

    Apr 5, 2000
    Madison, WI.
    >>Rick had a rig with 3 of them, as I recall.

    Ditto. I have the 301 w/ Acoustic 370 head.
     
  19. Mikeels

    Mikeels

    Apr 20, 2000
    So.CA.
    Awesome work MikeyD!
    I was at a Reggae fest. A couple of weeks ago. They had the front loaded twin 18 JBLs for subs.....a stack of four per side. They didn't sound half as good as the CVs at the track....could of been the engineer though as I know the speakers are good.
    is a bandpass about the same as a folded horn?
     
  20. perhaps bgavin and do not ream me out because I am no expert... The horn does not need to reproduce low E, just throw it.... the speaker produces it in the first place and like a sweet sweet port the horn throws that big low E out to the audience... any comments? I feel this is perhaps the case, and I do have some physics background...

    later bass-folk

    Drake