I know that many of the people here think that I'm wierd. Oh well....

I just started a new project because I was extremely bored at work and was playing around with the wo32 design.  I came up with something kind of interesting.  I don't know how well it will work, but after looking longingly at the SO IMP for what seems like a millenia I suddenly came up with an idea.

I want to try building a dual folded SO like WO32.  The idea is to isloate the horn from the driver in an extreme manner.  The horn is slightly lengthened, but the angle of the expansion is so wide that it shouldn't start working like an actual horn.  The drive is mounted in a speaker baffle that is paralell to the outside of the box.  The beginning of the horn is the same except that it comes to point.  The sealed chamber is increased in size to accomodate a 15" driver.  last but not least, the depth of the enclosure is changed to accept a 15" driver.

Oh, and some of the walls in the enclosure are doubled up to increase the stiffness.  I will be using MDF for the first few enclosures till I prefect it and then BB will be used.

Basically it works like this.  The driver is mounted in a speaker baffle that is separate from the opening into the horn and runs the entire length from the first bend in the horn to the outisde wall of the enclosure.  The horn wall stays the same in every way except for a tiny ammount of added length to bring the beginning of the horn to a point.  

The driver fires across a wedge shaped space, that is open on the large end to the room, and into the horn through a hole the exact diameter of the driver in the side of the horn. The hole in the wall of the horn is beveled at a 50 degree angle so that the vent las no length like a port would have.  

There is no guarantee that this will produce desirable results, it is just something that I have to try to build because I came up with the idea.  There is no engineering involved other than the volume of the sealed chamber, and the angle of the baffles.

This is going to be an unusual build even for me.

Finally!! got it done!! Tested it, tweaked it, can't turn it up though cause it is <<<LOUD>>> at low volumes!  I think it acts more like three horns!  I'm using two 10" mismatched subs at the moment.  One came from the KLH sub woofer I always use and the other is a 4 ohm memphis audio that was taken out of a car to be replaced by 2 12s.

I am running a mere 25W at 16 Ohms and no xover.  I don't really like it, but this box is definately producing something audible at 22 Hz.  ???  It doesn't come close to sounding bad though.  The crucial thing seems to be getting the right hole size in the wall of the horns.  my home made "iris" didn't cut it and kept flying apart even at low volume.  

A crumpled piece of paper in  the end of the wedge gets sucked inside  and eventually comes out the horn. (how intersting is that??????)  I wish I could show you guys a video!

I finally decided that using a slot instead of a round hole not only made much easier to adjust the opening, but over all sounds better. it seems to work more like the slots the pipes of a pipe organ.  Also, the sharper the angle at the opening, the wider the frequency range.  

This is a decent subsonic sub but has nothing like a flat responce below 30 Hz.  There is a short spike around 21-28 Hz that isn't very large, but is definately somewhere around 6 db. on the high side.  I can't hear it but I can definately feel it.

I am working on a matched pair of Polk Audio 10's, but I still have a LOT to pay off before I get them.  (I decided that I definately LIKE polk audio!);D

Could this be the best box I've ever built??

Well, I was thinking about giving the plans to Steve because his design is still there and I don't want to be giving away his plans.

That said I think that this is box is going to need a LOT more tweak time than I have time off of work at the moment. Perhaps after the holidays are done I can settle down to some serious tweaking.  

This isn't really a Graham Holliman in the sense that it doesn't have any of the real origional components.  What it does have is some serious deep bass if you can find media with that kind of bass concent. (approx 26 - 60Hz? It all depends on the size of the input hole in the horn.)  

I turned it up a little while ago and wasn't pleased.  Not only does the hole need to be the correct size it also needs to be in the correct place.  I think I'm going to move it FAR away from the driver and into the peak of the wedge. and then I think I may end up building a whole other box and changing a few more things that will make this thing howl out the bass.  

I think I like the idea of having high  Q. quality S. sound P. pressure L. level QSPL anyone interested?  

AHH HAA!!! I got it. I will make the wedge closed off on the big end and have a "triangular" opening in the small end of the wedge.  with a "triangular" opening into the horn the horn will better resonate at different and more freuqencies which will help to flatten out the responce!  Aint I genius? now for a way to cut a 20 degree bevel into the point of that triangle.... ???  could get a little complicated... ??? maybe a half moon would be better?  Maybe I should just leave it alone and leave the "horn organ" intact.

Closing off the wedge will definately add SPL but I'm not so sure about QSPL.  Only one way to find out...::)

Quote:


what did your version sound like?  Mine is in pieces and I ran into an idea while tinkering.  My problem is that I have to pick and choose the ideas that I want to try because I think of way too many at one time to even put them on paper. (the whole chain reaction thing)

I played it for the installer guy at Fry's electronics and he looked like he was suddenly angry about something.  The anger could have something to do with the fact that he insisted that we install some polk DB 10's and run about 300 Watts per channel.  I told him that it was WAY overkill and he wanted to argue about it so I took a 9 volt battery out of my pocket and stuck the hook up wires to the terminals of one driver.  (((THUD!)))  I sorely wish you could have seen this guy's face!!! not only was the thud loud, but you could feel it like a shock wave.

That ended most skepticism that I only needed power from the head unit.  I have never seen anyone want to argue so badly in my entire life.  I could feel it like a heat wave rolling off him.

I think that the thing that made him the most angry was the fact that at 11:00AM we had a crowd gathered at the car audio area.  Appearently the thing could be heard all the way in the manager's office because it wasn't long before he showed up too.

Every time the installer guy selected another speaker, one of the associated pushed the button for my sub.  boom boom boom (((THUD!)) boom boom boom booom (THUD!)) ((THUDD))  

My box definately goes "thud" I don't know how to describe it any other way because it doesn't sound like any other sub.  It is sort of a dryer sound than the usual sub.  It sounds a little but like the bass has been unconstricted the way that an ob sounds but with some slight harshness added to the deepest tones.  It sounds like the recording doesn't have all the bass included in the deeper tones.

Maybe you have experienced the same thing Gex?  Did it sound like the bass rolled off a slight bit too high even though you could hear deep tones? It isn't there when I play the tone sweep so I think it's the recordings.  On the cd's.

The store manager made us unconnect everything and put everything back the way it was because nobody in the store was doing any work. what a killjoy!

basically Gex it is the same idea as the SO, but the driver doesn't fire into the listening space.  You can see two 3/4 inch verticle slots on either side of the horn mouth (which is wider than the origional) when it is lying on it's side coffee table style.   These slots are widened an inch on either side at the mouth and resemble little horns.  I also use a diffuser that I constructed out of cardboard and fiberglass that lengthens the distance that the sound wave travels inside the center of the horn.

It is probably the most difficult build I have EVER done.  And it shames me that I feel compelled to take it apart time and time again to fuddle with it.  It already kicks some bandpass butt!

I've gotten away with 1/16th inch misscut and bigger before by using felt weatherstripping and a long piece of angle iron.

Method #1.  using dense felt weather stripping approximately 1/8th inch in thickness and cut to the same width as the MDF. cut ONE strip the same length as the gap.  Glue the waether stripping inplace with quality epoxy.  Weight the felt in place with a board and some books or a board and clamps. wait until cured. remove board and weight/clamps. ready the adjoining piece of material by marking screw holes. Drill holes for screws in the angle iron. Cover the exposed area of the felt with epoxy.  Work quickly! Secure the adjoining material with screws driven through the angle iron.  (Note don't drill holes in the MDF without using the angle iron for a template. And screw through BOTH sides of the angle iron starting on the side that will compress the felt into place)

Method #2. using a power pane, face shield, quality respirator, and goggles cut the rest of the panels down 16th inch.

also my design has a longer horn than the origional WO32.  The length from the horn mouth to the base of the triangle is longer... I'll have to look at the drawing when I find it. (I had a girl over and had to put many things "away" before she got here.) This may account for the higher efficiency.

The installer guy has taken a genuine liking to my design and wants me to build designs for Fry's for about $18.oo an hour.  I could see money signs in his eyes.  I told him "Hell" and let him take it as a no.  As long as he takes a non commital grunt as no I know I can get more pay.  Right??

He understands that he can't have the design or anything like it because it isn't even really mine, but decware's.  All I've done is modd an existing design that I don't even have the plans for.  If I did buy the plans then I would probably see all the wrong things I have done.

In my opinion the design still has way too many flaws.  I keep loading it up into my cousin's truck and taking it to Fry's because the manager is more than happy to help me test the deisgn and modifications I have done.  

This time I had to wait until the store closed to play with it, but the modifications have proven to relieve the harshness.  I removed all but three diffuser plates and no more thuding.  Instead It is deeper by a little bit and has lost some efficiency.  It still blows away the polk audio bandpass by a lot right off the head unit.  to me it sounds really SWEET, but many of the people don't like it anymore and said that it sounded better before i changed it.  

Next week I plan to install polk db 10's in the same style enclosure will the full diffuser panels and see what the two compare like.  Maybe I will start designing subs for fry's, but it seems like an uncertain future because I don't want my designs mass produced.  Maybe I will make a contract where the designs are sold as DIY plans in store.  

If I do it I will start with a fully adjustable tapered port fourth order I designed a while back and redesign it using the tools available at the install shop.

I have finally come close to a beta testing version.  I have tweaked and played around and come up with a 12 inch version that is less rumbly ane more punchy than the first one I did.

The driver is in a different position and the horn is nearly six inches longer than the origional rather than four inches.  I thought that using a 12 inch driver would be overkill at first, but then I remembered that the size of the driver doesn't make it louder.

The nice thing is that the thud aspect is totally gone with the 12 inch version!  It's softer and more musical!! I reduced the gap between the sound hole and the driver by more than 3/4 inch as well. The gap is definately only to eliminate the need for a cross over. and not to make the thing louder.  

Running with two polk audio db 12's it has plenty of sensitivity and is VERY loud with 75 watts.  hopefully I will be able to scan in the plans for you guys soon.

the measurements come to a mere 32 x 27 & 3/4 x 15 inches high.  I would reccomend it for medium to large rooms and open layout homes. (this thing has a tendency to make large standing waves sorry:()

Anyone got a scanner? I have everything completely mapped on paper, but I don't like to try and include measurements and draw everything to scale on graph paper instead.  Don't worry, it's easier that way.  Just make a ruler for yourself by marking a folded piece of paper with one mark for every line on the print out  and lable the marks 0 to 32.  Then you don't have to count lines or anything.

Note: I will only include the parts of the design that make up the midifications and nothing else.  To keep from posting copywrited information.

I just need a scanner.  Maybe the one at walgreens will work?? probably charge me money! oh well.