Orcus fullrange loudspeakers

[neebster]

Hello,
After much time spent poking around the diyaudio.com website, I decided to build a set of fullrange loudspeakers. For the build, I used Tang Band W4-1052SDF drivers.

Now, I had intended for these speakers to be modeled after a ported enclosure. Once I had it built, the gurus at diyaudio informed me I had inadvertantly built a mass-loaded transmission line. Whoops. After stuffing the speakers with some polyfill, I pretty much tamed the quarter wave resonances. Then, the final bit was to use my computer's 21 band pulseaudio EQ to flatten the response further. Success! I have a high fidelity speaker system!

For the base plates, I used some hardwood-veneer plywood, with speaker spikes. The speaker "tubes" are schedule 40 PVC (4 inch). Flat endcaps are attached to the base plates with wood screws. A few inches from the base is the port. Above this is a neutrik speakon connector. Then the top section is fairly densly packed with polyfill, and the top is terminated with the drivers, screwed directly into the edge of the PVC. Gasketing tape is used. It's powered by a Lepai LP-2020A+ amp.

All parts except the PVC and plywood come from parts express!

Dimensions: 4 inch schedule 40 PVC endcaps, 4 inch schedule 40 PVC pipes, exactly 30 inches long. The ports are 1 inch schedule 40 PVC, exactly 1.7 inches long.

It's a pretty simple and replicable build. Someone with no woodworking skills could build this in an afternoon. I hope others try it out!

[mikejennens]

What did you use to arrive at the tube and port size? I have some 2 inch Tang Band drivers I'd like to try in something like this. You have a very nice looking build. Are you not missing some of the highs with the driver pointing up?
Thanks,
Mike

[neebster]

I used some of the freely available ported enclosure calculators available by googling, and cross-checked results.

I obviously should have used Martin J King's MLTL spreadsheets but was not yet aware of them when I built the speakers. However, the stuffing with polyfill and EQing seemed to fix the albeit-slight mis-modeling.

As for loss of highs, this is true. I have the EQ set to correct for this. Also, my particular listening room happens to have ceilings that sort of horn load the room, which helps. The positive side effects, however, are wonderful room ambience and wide soundstage.

In the future I will get a mini-DSP and some forward-facing helper tweeters, ala Linkwitz's Pluto 2.

If you were going to do a different driver, for modeling it, I must recommend MJK's worksheets (I think they're about $20)

[thekorvers]

One solution for the missing highs would be to mount a triangular inverted hard cone above the driver.

Another more unusual, but also more difficult solution, would be to build and mount a "conque" above the driver. This is an older design, dating from I believe + 1960, invented in France. It is basically an elliptical reflector which produces an unbelievable spatial sound field.

http://passion-elipson.com/html/ft/ft144.htm

http://passion-elipson.com/html/ft/ft81.htm

These can be mounted lower than shown (floor standing).

For those of you who speak french:

http://www.passion-elipson.com/

[AR3A]

I will be building a set of these

[neebster]

AR3A, glad someone is interested. Post back if you build a pair. I'd love to hear other audiophile's listening impressions.