DrWho Posted May 16, 2011 Share Posted May 16, 2011 Done gone built a new speaker for the gym at church.... The design is using a pure tractrix area expansion on a bifurcated bass horn to help spread out the HF polars and provide more directivity down low. The frequency response plots are gated anechoic with no smoothing. The third plot is showing the raw frequency response on-axis, and then every 12.5 degrees and ending at 50 degrees. The 4th plot is showing the same data, but normalized to the on-axis response (which is what it should look like after EQ). At 50 degrees we end up with just as much highs as we do lows! (ignoring the 300-500Hz dip) As far as sound quality, I think they sound amazing, and they're not even done yet. We had it cranked up to 125dB and the system was just cruising along at ~50W RMS. The peak power handling is ~800W. We used the speaker last night for sound reinforcement during a dinner in the gym, and we didn't need to run any EQ on the vocals or anything....and the person was talking just below the speaker. The polar control on this guy is very well behaved. The LF is using two B&C NDL76 12" drivers. The tweeter is the HF horn from the QSC HPR152i with a BMS 4550. It worked out real well that we were able to mount the tweeter coaxially with the midbass. There's still a lot of work yet to be done. The LF corner isn't meeting the design prediction, and several of the pieces haven't been glued all the way yet. We also need to adjust the rear volume to get the right reactance annulling...my new WT3 woofer tester just showed up today [] Major thanks to Mike Hurd and Kurt Knautz for all their help in the build. I've been working on this for ~3 years now, so it's very satisfying to see it finally come together. 1 Quote Link to comment Share on other sites More sharing options...
Boxx Posted May 16, 2011 Share Posted May 16, 2011 Thanks for posting... Excellent photo's and craftsmanship.... Quote Link to comment Share on other sites More sharing options...
Guest " " Posted May 16, 2011 Share Posted May 16, 2011 Awesome ..,,, Quote Link to comment Share on other sites More sharing options...
Guest David H Posted May 16, 2011 Share Posted May 16, 2011 That is amazing, a standing ovation is in order. Nice work. Dave. Quote Link to comment Share on other sites More sharing options...
Coytee Posted May 16, 2011 Share Posted May 16, 2011 Very cool! It looks a bit like one of those slicers that you might push things through to make for example, jullianne fries... except this is more like for Jullianne Elephants... Not that I've ever seen Elephant fries... Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted May 17, 2011 Share Posted May 17, 2011 I saw that over at the avsforum and wondered if you'd post it here. Great job, very impressive!! Quote Link to comment Share on other sites More sharing options...
mark1101 Posted May 17, 2011 Share Posted May 17, 2011 You better delete the pics and that design before that thing becomes a church-a-torras. Quote Link to comment Share on other sites More sharing options...
crd97086 Posted May 17, 2011 Share Posted May 17, 2011 That is very cool! Quote Link to comment Share on other sites More sharing options...
CAKE Posted May 17, 2011 Share Posted May 17, 2011 WOW ! PROPS to you! How do you get the crane in the room to move it? Quote Link to comment Share on other sites More sharing options...
jorjen Posted May 17, 2011 Share Posted May 17, 2011 Way to go Mike! Nice work. Quote Link to comment Share on other sites More sharing options...
DrWho Posted May 17, 2011 Author Share Posted May 17, 2011 Each half only weighs 210 lbs....Hurd and Kurt had no problems carrying them up an extension ladder. I carried the tweeter [H] Quote Link to comment Share on other sites More sharing options...
DrWho Posted May 17, 2011 Author Share Posted May 17, 2011 Very cool! It looks a bit like one of those slicers that you might push things through to make for example, jullianne fries... except this is more like for Jullianne Elephants... Not that I've ever seen Elephant fries... If you've got an elephant, I'd be willing to try it out... Quote Link to comment Share on other sites More sharing options...
greg928gts Posted May 17, 2011 Share Posted May 17, 2011 I like it! Nice work. Is there a method you used to determine the offset of the horn mouths (driver off center, angle of the mouth)? I don't know if I'd call that a bifurcated horn. Each horn has it's own driver/throat/mouth with no split. Seems more like a two speaker array. What will the finish be? Will the inside of the horn be coated with something? Joints sealed? Greg Quote Link to comment Share on other sites More sharing options...
DrWho Posted May 17, 2011 Author Share Posted May 17, 2011 I wrote about 200 lines of Scilab (matlab) code to derive the shape based on desired polar response while maintaining a tractrix area expansion. The horn only works when both halves are present - splitting it into two made it way easier to build and then allowed tweaking of the splay angle. We're going to sand / fill the speaker so that we can paint it the same color as the walls/ceiling in the gym. The corners will get a nice roundover and we still need to add the handles. The screw holes inside the horn will get sanded and filled, and the horn will get painted too. We were gonna spray it, but since it'll be so high in the air, we're probably just going to roll the paint on instead. Quote Link to comment Share on other sites More sharing options...
JJkizak Posted May 18, 2011 Share Posted May 18, 2011 I remember that PWK said the front openning for a 15" horn would be somewhere around 66 ft. Wondering if the two 12" would knock that down to 33 ft. JJK Quote Link to comment Share on other sites More sharing options...
TheEvan Posted May 18, 2011 Share Posted May 18, 2011 My jaw is on the floor! That will certainly get the Spirit moving in the house of God. Eh. Quote Link to comment Share on other sites More sharing options...
DrWho Posted May 31, 2011 Author Share Posted May 31, 2011 I remember that PWK said the front openning for a 15" horn would be somewhere around 66 ft. Wondering if the two 12" would knock that down to 33 ft. Was that 66sq ft? It seems to me so far that the horn can get shorter by going to a larger radiating area in the throat, but then I think you sacrifice HF polars in the process (unless you go to some sort of phase plug / combiner approach). I don't think you can get by with a smaller mouth though... Quote Link to comment Share on other sites More sharing options...
Moderators dtel Posted May 31, 2011 Moderators Share Posted May 31, 2011 You better delete the pics and that design before that thing becomes a church-a-torras. They will probably be for sale here and not by DrWho with a different name for it, and as if they designed it or even have a clue......or like normal just take credit for it in all there brilliance. [8-)] Very cool looking DrWho. [Y] Quote Link to comment Share on other sites More sharing options...
mark1101 Posted May 31, 2011 Share Posted May 31, 2011 The claim will probably be that it has been improved...........and that it isn't being advertised on Klipsch's website. Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted June 1, 2011 Share Posted June 1, 2011 DrWho, Awesome work and gift for your church. Would love to hear the sound in the building. Quote Link to comment Share on other sites More sharing options...
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