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Horn vs reflex

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DMorison View Drop Down
Young Croc
Young Croc


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Post Options Post Options   Thanks (0) Thanks(0)   Quote DMorison Quote  Post ReplyReply Direct Link To This Post Posted: 22 September 2017 at 1:19pm
Originally posted by king david king david wrote:


i have 4ohm version of b&c 18pzb100, run by an ffa 6004, so ideally its 1500w/box but with a limiter they never see any clip, mostly just flashing the -3db light...
the crossover slopes are 24db LR and eq is -1/2db at 150hz.
since a 15"reflex box is around half es18, yes, i'd go for singles.
basically this is the system, its sounds good, es18 sound good, maybe i'll keep them, with the 15" option if i have to set up all by myself

OK, couldn't find TS parameters for the 4Ω version so had to make some assumptions.
It looks like at full power from that amp with 4 ES18's coupled you have a theoretical 141dB max around 80-90Hz (assuming no power compression), and -5dB from that at about 55Hz. (Modelled in full space as the bass bins (Hogs?) + decking put the bottom of the box about 1.1m above ground level.)

Based on that, and assuming you'd like the possibility of using the kicks as general purpose bass bins for smaller events, I think you would need 8 15's to keep up.

That's based on modern drivers like B&C 15NW76/15NDL88, 18Sound 15NLW9300 or similar with vent tunings around 55Hz and boxes around 60-80l net internal volume - which will be a LOT smaller and lighter than your ES18's, and driven off your existing amp (2, 8Ω 15's per channel). They'd be small enough that you could make all 8 fit across the same width as your scoops easily enough to make the stack look coherent.

You could drop to 6 drivers, if you were willing to give up about 2dB of max output.
You could salvage some of that loss by tuning higher, but that tends to result in a more peaky response in the half octave or so around the tuning frequency, which may not sound as good and may make integrating the box with the rest of your system harder.

Pic shows ES18's on top, 15NDL88's below.

HTH,
David.





Edited by DMorison - 22 September 2017 at 1:20pm
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king david View Drop Down
Young Croc
Young Croc


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Post Options Post Options   Thanks (0) Thanks(0)   Quote king david Quote  Post ReplyReply Direct Link To This Post Posted: 22 September 2017 at 3:20pm
Thats Great
So lets say 8 x 15" b&c neo midbass drivers (so not The tbx ps pzb or nw100 ) in a box similar To An x15 without The compression drivers should do It. ..
http://www.warriorcharge.noblogs.org
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DMorison View Drop Down
Young Croc
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DMorison Quote  Post ReplyReply Direct Link To This Post Posted: 23 September 2017 at 1:42pm
Originally posted by king david king david wrote:

Thats Great
So lets say 8 x 15" b&c neo midbass drivers (so not The tbx ps pzb or nw100 ) in a box similar To An x15 without The compression drivers should do It. ..

I only looked at Neo as your goal was easy transport/stacking, it's possible some of the ferrites will be just as good as the ones I mentioned, I just haven't checked.

The ones that are specifically aimed at sub use (NW100, presumably TBX too etc) usually want bigger boxes and lower tunings, which means they'll be less of an advantage for size & weight, and will be a little less efficient in the upper bass region you're wanting to operate in, and will run out of excursion earlier, so I wouldn't recommend them.

You do however want something with high Xmax (or Xvar if we're talking B&C); all of the ones I suggested have at least 8mm.

You could use a trapezoid shape like the X15 if you want, the boxes will be quite shallow (front to back) if you make them cuboid and that might make it awkward to stack your tops, so a trap is not a bad idea.

Regards,
David.
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king david View Drop Down
Young Croc
Young Croc


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Post Options Post Options   Thanks (0) Thanks(0)   Quote king david Quote  Post ReplyReply Direct Link To This Post Posted: 03 October 2017 at 10:02pm
Today we made a quick test, ES18(w/b&c 18pzb100 4ohm)  vs 2 x sub15 (w/b&c 15pzb100 8ohm), i will post graphic results later.
since i dont need a full band test, and the weather was turning to rain (we did it outdoors), we went to test the boxes on the frequency i would mostly use them, upper bass limited to 80-150hz.
they were really close in SPL, if i remember correctly the ES18 was slightly better at 80hz and the 2 x 15 were a bit louder around 150hz, but all was like 1db...they dont sound the same but also they arent that different, maybe because they are doing just a narrow range of frequencies. I didnt stay too far from the boxes and up close, 5/10 meters away the reflexes were sounding a little nicer
Since the 2 x 15 would handle twice the power, they can outperform the ES18, but i think i would need minimum 6 of them with a lot of amp power to equal my 4 ES18 how i run them now.  
thanks speakerplan member leru sound for doing all measurementsClap


Edited by king david - 03 October 2017 at 11:26pm
http://www.warriorcharge.noblogs.org
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