More bass horns in progress

[wg_ski]

Missed the design goals by three inches - the fold just wouldn't fit in 36x36. But 4 should still fit in the bed of an F150 (pointing up). All pieces are cut out, ready to start up the air nailer. I had one mocked up the other day - these should be way easier to assemble than the labs were. Simulation is 1/2 pi (four on the floor). Driver is Kappa P15LF2.

Progress got delayed a couple weeks because I ended up doing the prom this year. These will be just about the right size for next years.

[Wolf]

Re: More bass horns in progress

Have you entertained the new LAB15, Warren? Just wondering.
Wolf

[wg_ski]

Re: More bass horns in progress

Not for this application. I designed around the KP15 because I had them. The LAB15 looks like it was developed specifically for tapped horns - which may be coming next. The project I 'stole' the Kappas from was a large 4 way full range that is being redesigned to a 3 way with a tapped horn sub. I was going to use DVC15's, but the LAB15's handle more power.....

[Paul O]

Re: More bass horns in progress

Interesting design.. I'm looking forward to your thughts on how they compare to the labs. It's hard to believe you need more bass horns so maybe you're goal is something a little more portable?

[Guest]

Re: More bass horns in progress

Looks very good so far. I'm curious about the half-panel that is in front of the driver and parallel to the baffle; the beginning of the horn path, so to speak. Does the driver have some kind of a splitter or loading device in front of it? One that is on a different axis and obscured by the baffle?

I've seen similar designs that start the horn flare right in front of the driver baffle -- in the case of your image the half-panel would touch the baffle at an angle on the left hand side. Does that make sense? I've read suggestions that this approach maintains the proper horn taper from the outset but also might possibly load the driver diaphragm assymetrically.

I'm sure you know you will need a lot more duct tape to hold those guys together when you're finished.

Nice project!

Regards,

SC

[david_b]

Re: More bass horns in progress

wg_ski,

Nice job squeezing a lot of horn into a very small space!

when you design a speaker like this, how do you determine the volume for the chamber behind the speaker? Do you use the standard approach for sealed box like you would get out of WinISD? Or does the sizing of the rear chamber depend on the parameters of the horn on the front size?

Thanks,
David

[wg_ski]

Re: More bass horns in progress

I've seen similar designs that start the horn flare right in front of the driver baffle -- in the case of your image the half-panel would touch the baffle at an angle on the left hand side. Does that make sense? I've read suggestions that this approach maintains the proper horn taper from the outset but also might possibly load the driver diaphragm assymetrically.

This design, like everything else, wasn't going to let me have everything. I fought with the fold for two months off and on, and of course, you run out of room. I finally settled on this, which doesn't obstruct the diaphragm too much, and was as symmetrical as I could get it. The panel on the left side of the baffle is positioned to center the opening, which is about 12" wide (when it's nailed together, not duct taped). I've seen a lot worse implementations.

[wg_ski]

Re: More bass horns in progress

wg_ski,

Nice job squeezing a lot of horn into a very small space!

Thanks. It does help if you've built a few of them. My first solo horn effort (80 Hz mid-bass bins) had some wasted space.

when you design a speaker like this, how do you determine the volume for the chamber behind the speaker? Do you use the standard approach for sealed box like you would get out of WinISD? Or does the sizing of the rear chamber depend on the parameters of the horn on the front size?

Thanks,
David

Use Hornresp to do horn models. Modern versions will do virtually any enclosure, even the stuff you use winISD for. The rear chamber does affect the overall compliance, just like a regular box. And I'm sure you could correlate with winISD results with enough math in between, but that's way too much trouble to go to when the proper modeling tool is available. In the end, the front and rear volumes are just parameters that you tune - there are optimums for a given driver and ranges that will give acceptble results.

[wg_ski]

Re: More bass horns in progress

Interesting design.. I'm looking forward to your thughts on how they compare to the labs. It's hard to believe you need more bass horns so maybe you're goal is something a little more portable?

I found myself going back to DJing school dances again. The 2x18's work, but they distort too heavily long before the 2450 clips. The labs do fantastic - but moving 3 of them by myself for a 2-3 hour gig is a little much. I don't mind that much work if it's going to be set up outside all day/weekend.

[wg_ski]

Re: More bass horns in progress

See - real hardware, not vaporware. These actually got done almost a month ago, but I had some trouble recovering the pics.

Drivers (KP15LF2's) and lids have since been installed and yes, they make bass. They have the same low distortion bass I've come to expect from horns - they should totally replace the 2x18's. With output somewhere between two and three labhorns, and are a one-man load in/out. No measurements yet, but they sure sound like they're flat to 40. No paint or casters yet, but that's coming. They'll probably still be raw plywood boxes for the first few gigs.

[jhollander]

Re: More bass horns in progress

Very cool, nice picts. I've always wanted to build one but now it sounds like with some software I might be able to design one too...

Thanks for the inspiration.

[AMC]

Re: More bass horns in progress

Very nice. Couple of questions...

Did you cut the bottom corner off for casters, or are you going to put them on the back?

Just for giggles, could you share you HornResp inputs?

Is that all 3/4 inch?

What were the final exterior dimensions?

I am impressed in the way you built them, Building all the baffles as a free standing unit would be tough. When I build mine, I build the internals on to one of the sides, just to keep it aligned up right. Is there some trick to keeping it all square and true?

Good job.

[wg_ski]

Re: More bass horns in progress

The casters I intend to use are these:

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=262-278

Notch the back corner and install. There's a handle on the back so they will tilt and roll. I have these on some of my other boxes - including the labhorns which take all of my weight and some momentum to tilt before rolling. These will be easier. The boxes are all 3/4 inch, exterior is 36x39x22.5. With two if them "end up", the quad will fit in an F150 short bed (exactly 78" inside).

The other design goal was actually ease of assembly. The fold was layed out on a piece of 1/4" ply, and the cut sheet made from the resulting measurements. The four sets of innards were put together using the layout as a guide and that kept things lined up. I let the innards dry compeltely before putting the shells around them. I still have the layout panel for when I go to build more. There was a wee bit of belt sanding required to level everything off for a good seal before installing the second side panel.

Hornresp files and the flare rate spreadsheet are on the other computer. But what I do recall off hand is a cosh with 97" path and 38 Hz or thereabouts cutoff, designed for a 4 pack or greater. No one can have (eat?) just one.

Thanks for the interest.

[wg_ski]

Re: More bass horns in progress

The inputs....

I got the spreadsheet from somewhere back in '02 or '03. Probably from the LAB, but I'm not sure now.