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Cabinets with folded horns

Discussion in 'Amps and Cabs [BG]' started by LeftyLB70P, Aug 4, 2005.

  1. LeftyLB70P


    May 4, 2005
    Athens, Ga.
    I have begun using Acoustic amplifiers in the last few months and as I am trying to learn more about amps & cabinets from the 70's I see that Acoustics in particular really used 18" cabinets w/folded horns.

    I do not see that much when looking at bass cabinets that are popular today. Can someone please shed some light on this for me? I am wondering:
    Am I just not noticing folded horn cabinets b/c I wasn't looking for them (NOTE: I know that it is easy to find them when specifically looking, I am more curious as to why I don't see AMPEG, ACCUGROOVE, SWR, etc,etc folded horn cabinets, etc) or
    Has technology been developed that made that particular design a moot point?

    Thanks for any info.

    Oh, wait;
    as long as we are on the subject: Can anyone speak on the difference in tone/freq. response/ whatever between various popular size cabinets. I.E. 2x15" vs 1 18" vs 2x12" vs 4x10" and such.
  2. protoz


    Nov 30, 2000
    Sunn's and Acoustic gear was very unique for their time. The only company I see that has folded cabs anymore is Schroeder which I hear are amazing cabs but you pay a premium price.

    The folded design added to the volume of the cab and gave it more rumble. I think in the Acoustic cabs they have a cab with 2 15's facing each othervertically and the air is pushed out between the gap between them and they are tone monsters!
  3. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    Folded horns are huge. At least they are if they have reasonable horn flare rates, and "mouth" sizes.

    Folded horns (unless back-loaded) are also way deficient in highs, because highs just don't make it down the horn around all the internal corners. The usual way around that is to load the rear of the cone with the horn, and let the front side direct radiate. That gets into some physics oddities, though, and the cabinet is still huge, although it can be done.

    There are various ways to try to get around the "huge" factor, but each one has its own set of drawbacks. Mostly they relate to the low end being weaker, because the flare rate of the horn (how fast it expands) is related to the low frequency response. Short horns have a higher "cutoff" frequency, below which there is a fast rolloff. Around the cutoff frequency there can be fairly wild "bumps" in the response if the horn is short, even with the right flare rate.

    Horns are really tied to the frequency range as far as size and shape. In the limiting case, as you shorten the horn to nothing, you end up with the basic sealed cabinet.........

    So basically, nobody much wants to haul them, despite the fact that 50W would purely tear up a big room if using an efficient horn speaker.
  4. 4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge
    Basically the 360 made up for the deficiencies of the cab via the voice of the amp. A classic for sure but not really a very good sounding amp. Yes, they had balls, very large ones at that. Put one next to an SVT of the same vintage and you wouldn't look at it twice. Still, they got huge volume and very long throw for the money and wattage at the time.

    There were a number of companies on the east coast in the early 70's that specialized in folded horn pa cabs. You needed to tri amp using something in the mid bass through upper mids before crossing into your horn. These were mostly based around EV 15's and they were pretty decent sounding cabinets. Electro Voice did one as well with their Sentry IV cab which is certainly a PA classic for all time. Right there with the JBL 4560 and Altec A7.

    The folded horn designs went the way of the dodo though. Front firing drivers just sound so much better. The JBL scoop design kind of ruled in the late 70's through the mid 80's, along with EAW's bent horn design. I actually ran two single 15" scoops on stage as my bass rig for a while. Of course lugging around a pair of 4 foot tall, 2 foot square cabinets for single 15's get's old quickly... still, they were very efficient and had booty to spare!

    To my knowledge, Schroeder is making something other than a folded horn cab. That side firing arrangement is not really a horn. Probably the closest thing out there would be Bill FitzMaurice's tuba design but that design is light years beyond the W bin. (and Bill would probably be p/o'd that I'd even bring his cab up in a comparison to a W bin...sort of a F350 vs the Ford Ranger kind of comparison ...)

    Acoustic did make some cool stuff though. The 370, 470 and 450 heads among them. Some of their front firing cab's rocked as well. The 450 head into their 2x15 front firing or the 1x18 front firing was a hot setup for the club band set there for a while. There really aren't that many vintage bass amps I'd even think about in this day and age. There are even fewer solid state ones. A 450 in decent shape I'd have to seriously consider ...
  5. Fealach

    Fealach Guest

    Apr 23, 2003
    Gone to a better place
    You could always pair up your folded horn with another cab, say a 210 or something. I used to have a cool folded horn, but it was just way too much boom than I needed for the tiny spaces I played in. It was a cool cab though, and unique among folded horns, because.... it also had a front firing 12!

    Cerwin Vega B36MF. Awesome cab if you like old school earthquaking, and play in stadiums. The 12 actually gave something audible (I had changed mine to a Carvin bass 12) and the 18" folded horn could be sensed by elephants for 26 miles.
  6. Doug Parent

    Doug Parent Gold Supporting Member

    May 31, 2004
    San Diego, Ca.
    Dealer Nordstrand Pickups.
    Folded horns never made the comeback that bell bottoms did for a good reason. Only problem is I smoked so much weed in the 70's when I HAD a folded horn, that I forgot what that reason is. :p
  7. I ran across a pair of JBL 1x15 scoops for sale recently. Price was $100 each including the JBL, but the drivers were wrong so I passed on the deal. The scoops are indeed huge. I could not have gotten one into my Toyota mini-pickup unless I removed the shell.

    As large as they are, a single one does not have sufficient mouth area for full horn loading down low. Like the LAB subs and every other horn, sufficient horns are required to get this mouth area. The Tuba design is indeed miles ahead of the scoops on several points. F350 vs Edsel is the comparison that comes to mind. The Edsel was ho-hum in its day, but less than useless today. The F350 is a workhorse, but a big one.

    I will be able to squeeze two Tuba 30 into my Toyota without removing the shell. My plan is to build 4 total, and slim them to 28" wide so they will fit two-wide into a standard 5x8 cargo hauler.

    The commercial manufacturers do not make these due to the amount of labor required. After markup is applied, they would be too pricey. Bass horns are alive and well in the DIY market, and not beyond the skills of a patient duffer wood wooker with a few tools.
  8. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Not at all. The DR series are W horns. The DR250 has it's heritage in the 301 or Ampeg V4. The Tuba is a spiral horn, though, so there's no resemblance there.

    The Schroeders are horns, but they aren't folded. They're too short to horn load the driver output below 200 Hz, so they aren't basshorns, but the acoustic air mass load on the driver even with such a short path does improve the bass response of the driver, though operating in direct radiator mode.

    The CV folded horn, and the half dozen variants of it from other sources, is a thirty-plus year old design. It was better than contemporary direct radiator boxes, but today the path length is too short to justify the size of the cabinet. Modern designs get a lot longer horn, and therefore a lot lower response, from the same size package, if not even smaller.

    There are plenty of modern design folded horns out there, but because they do have high labor costs you don't see them offered for the most part at less than $2500. They also tend to be a lot larger and have far higher output than anyone really needs for backline use. Folded horns intended for the backline exist, but only as DIY, where labor cost is a moot point.
  9. BassGreaser


    Aug 22, 2002
    Austin, TX
    I'm having an Omni 12 made for me which I think is more like the Schroeders design, but is only going to cost me $350. :D