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A 12 inch horn loaded MTM top: 12NDL76 and N314T-8
A 12 inch horn loaded MTM top: 12NDL76 and N314T-8
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Old 24th March 2017, 06:13 PM   #11
msibilia is offline msibilia  United States
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Originally Posted by chris661 View Post
I have the same horns. Rather nice, not much EQ needed to get something good.
I'd recommend being able to tilt them down if possible, though - 40 degrees vertical is fairly narrow.

Chris
Did you do anything to seal the 1.4" adapter into the horn? I took a little foam weatherstripping, put it in the gap, attached the adapter, then trimmed the excess in the throat. It seemed like a fairly loose fit without something, and I was worried about performance reduction due to leakage. Did the horn come with an adapter gasket? Mine was in opened manufacturers box.

Marc
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Old 24th March 2017, 06:46 PM   #12
chris661 is offline chris661  United Kingdom
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My horns were second-hand, with just the 1.4" adapters. The previous owner had used hot-melt glue on the outside to make sure things are sealed. No idea if it's helped, but it can't hurt.

Chris
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Old 25th March 2017, 10:25 PM   #13
msibilia is offline msibilia  United States
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I got outside today and did some testing. It started to sprinkle when I was set up for 10 minutes. I managed to get in about an hour of testing and tuning before I chickened out and packed up. I got the highs and mids EQed and well integrated, and the bass EQed but not integrated to my satisfaction yet. I was unable to get any polars yet.

I stacked two subs, with two more empty sub cabs on top, then the top. The horn was 98 inches off the ground. I am using a miniDSP 2x4 IIR for crossover and EQ.

First plot shows the each driver without crossover (the compression driver I used a Butterworth 48dB/oct at 500 Hz for protection). The second shows after equalization.

I took pink noise SPL measurements at ground level at 5 meters along with RMS voltage measurements of each section with its EQ and crossover and calculated average sensitivity in band for 2.83 Vrms at 92 dB for a single sub, 107 dB for the mid, and 111 dB for the compression driver and horn. Fully powered that should be 140 dB for eight subs at 1000 W each, 136 dB for two mid cabinets at 400 W each, and 134 dB for two high horns at 100 W each. Looks like I need more sub (which I won't be able to move), or my tops will just be loafing along (it probably sounds better that way).

I only got to listen to a little music and not too loud, but I liked what I heard.
Attached Images
File Type: png Sub mid horn no EQ.png (134.9 KB, 527 views)
File Type: png Sub mid horn w EQ.png (106.9 KB, 518 views)
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Old 26th March 2017, 01:44 AM   #14
swapnilsound is offline swapnilsound
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Share complete plans for it I still can't understand the pannel of front and back side.

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Old 26th March 2017, 02:43 PM   #15
msibilia is offline msibilia  United States
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Originally Posted by swapnilsound View Post
Share complete plans for it I still can't understand the pannel of front and back side.

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Please go back and re-read post 7. I said that eventually I will make up a drawing. This speaker is still in development. If you need something in a hurry, there are a myriad of designs posted around the internet that have been fully designed, tested and built multiple times. If you are savvy enough, you can use this design as is with what I have already posted. As for myself, I will probably be happy with these for my purposes, but they are, as yet, unproven.

Marc
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Old 28th March 2017, 11:29 AM   #16
msibilia is offline msibilia  United States
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I took the first crude polar measurements this morning. Just rotated the speaker on top of the subs in my cluttered basement. The transition at the 1000 Hz crossover looks good to me. The directivity is nice and smooth. The anomalies at 8kHz are LR asymmetric, so it's probably the room.

Marc
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File Type: png Horizontal polar.png (121.5 KB, 495 views)
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Old 28th March 2017, 06:36 PM   #17
chris661 is offline chris661  United Kingdom
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Not bad!
Looks like the crossover region around 120Hz could use a little work, but even that's only a 5dB dip.
Good results there.

Chris
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Old 30th March 2017, 01:59 AM   #18
msibilia is offline msibilia  United States
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I got the lower crossover sorted. It is sounding really good. Now I need to a little bit of bracing in the horn to clean up a couple of small resonances and then get the rest of the drivers and build the real cabinets. I need to get outside again to get some clean measurements, but it won't be this weekend: tax filing time

Marc
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File Type: png Sub mid horn EQ S.png (70.7 KB, 469 views)
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Old 30th March 2017, 03:32 PM   #19
Thijs666 is offline Thijs666  Netherlands
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Looks promising, Marc! Flat to 40 (with subs)?
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Old 31st March 2017, 01:09 AM   #20
msibilia is offline msibilia  United States
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Yes. Definitely with subs. Top is only good down to 130 Hz. My last tops crossed at 250 Hz, so I am much better off than before, but the new top won't cross as low as some people would like. I did find it kind of hard to get a ported top to mesh nicely with the subs when using the top's full bandwidth down to port tuning. It's not impossible, but it took 10.0 ms of delay of the horn mid and 12.24 ms delay of the high horn.

The subs should be good down to mid 30's but it's not worth playing with in my basement because I have serious room modes to deal with.

Marc
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