A 12 inch horn loaded MTM top: 12NDL76 and N314T-8

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I finally got around to plotting up the polar data I took back in September. The horizontal looks very good at +-30 degrees and tilts down gradually and smoothly. There is slight waistbanding at 1500 Hz, but blends well to the directivity of the mid horn. Horizontal data were taken at 15, 30 and 45 degrees each direction and averaged.

The vertical is definitely more of a mess off axis, but it is within 3 dB to +- 20 degrees, so it should be very good for outdoor events where everyone is at roughly the same elevation. Vertical data were taken at 10, 20, 30, 40, and 45 degrees in each direction and averaged.

msibilia, would you mind sharing your drawings?

I hope to get to making some drawings soon. But I move kind of slowly on my projects lately.

Marc
 

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I finally got around to plotting up the polar data I took back in September. The horizontal looks very good at +-30 degrees and tilts down gradually and smoothly. There is slight waistbanding at 1500 Hz, but blends well to the directivity of the mid horn. Horizontal data were taken at 15, 30 and 45 degrees each direction and averaged.

The vertical is definitely more of a mess off axis, but it is within 3 dB to +- 20 degrees, so it should be very good for outdoor events where everyone is at roughly the same elevation. Vertical data were taken at 10, 20, 30, 40, and 45 degrees in each direction and averaged.



I hope to get to making some drawings soon. But I move kind of slowly on my projects lately.

Marc

Great project Marc ! Saw you on Peter's Soundforum DIY thread....
I especially like the way it's all engineered to fit in your van, and that it's a one man groundstack..
 
PA in the wild

I apologize to you swapnilsound that I haven't gotten around to making detailed drawings yet.

But I did get the system out in the field today. I ran it off a Honda EU2000i, and the no sound power draw was 240 watts on my Kill A Watt and the highest I saw today was 340 watts. I measured 80 dBA slow and 101 dBC peak at 100 feet with a crudely calibrated cellphone SPL app. The NU4-6000's were lighting the -24dB light intermittently, but never lit the -12dB light. I am still waiting for a time and place to really let it loose.

A couple pictures and a link to a smartphone video.

It sounded really good to me. It didn't sound quite as boomy as the video.
 

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