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12 inch hybrid horn

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pfly View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote pfly Quote  Post ReplyReply Direct Link To This Post Topic: 12 inch hybrid horn
    Posted: 10 January 2010 at 1:17am
This is something I've been designing for some while now and I am now currently building the first prototype, the horn flare is pretty much ready, just need to build access panel and all the small stuff. If it turns out to be anywhere near promising, I'll build a second one because I have two drivers already.

Some of you may remember my slightly odd plan of same sized mid and bass sections that could be stacked pretty neatly. I think the most important thing in that idea is the outer size, outer dimensions of 86*86*43cm. That size has been my starting point and a limit and I've been drawing and simulating many different configurations, 6th order BP, push/pull reflex, Wicked one -style BPH, 
full length 40hz horn... There are some advantages in that size, I think that it is pretty convenient size to haul around by myself or specially by two people, like Rog said with Arcline X, really high performance bass stack can be assembled by two people in matter of minutes. 40cm inner panel width also gives the advantage of using 122cm wide ply sheet efficiently. Two of these form perfect cube when stacked and van packing should be a breeze too.

From commercial designs Arcline X is almost of the same size and gives 103-105dB/1w/1m around 40-200hz while having total displacement/size of 306,8 liters, its power handling is something else, though. Outline has design called "Lab15" that has exactly the same dimensions that I have used, it uses 15" driver and seems to be some kind of tapped horn. 101dB quoted "max" sensitivity, 1000W cont. power handling and -3dB @ 42hz. They seem to be making great deal of hype from that "new" idea of having symmetrical dimensions. 86*86*43cm comes out 318 liters, so Outline cab and my design are marginally bigger than Arcline X.

The closest thing that comes into my mind would be the Punisher. It is DIY, cheap and with dimensions of 70*81,5*50 comes out 285 liters small. I do not know how it really performs but having heard good reviews from many people. My design should be able to go approximately as low as Punisher but should be also able to reproduce more defined and punchy midbass. Also my hybrid horn is somewhat easier to construct.

The sims show some ripple with 2pi single cab, but they smooth out pretty nicely when multiple cabs are used. I'm pretty certain that if all works out nicely and those peaks are also there with the real thing, they could be smoothed out with an EQ and the thing would be usable in singles too.
Driver used here is humble PD.12SB30 and one cab takes around 3-4 square meters of 15mm ply so it should be pretty cheap thing to build. No mitre angles of over 45 degrees so it should be pretty DIY friendly. I simmed many drivers from Beyma, 18sound and BMS but only one showing tiny (1dB more sensitivity) improvement over the PD was the heaviest and the most expensive 18sound model, not worth of money I think.

Here we go:

2,83v single 2pi:


2,83v double 2pi


2,83v four cabs 2pi


2,83v eight cabs 2pi



Edited by pfly - 10 January 2010 at 2:29am
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pfly View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote pfly Quote  Post ReplyReply Direct Link To This Post Posted: 10 January 2010 at 1:19am





Edited by pfly - 10 January 2010 at 1:24am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote pfly Quote  Post ReplyReply Direct Link To This Post Posted: 10 January 2010 at 1:23am
I'm going to build the handles in both side walls, so one handle is going to be in the access panel, and another in the port, also I have all the bracing and that stuff ready, these pics don't show that stuff.

The handle box in the shelf port worries me a bit but I would be measuring and fine tuning the port length anyway.

Has anyone got any tips, or does someone notice some immediate flaws in this design? I hope next week I have at least one prototype working.


Edited by pfly - 10 January 2010 at 1:24am
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Centauri View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Centauri Quote  Post ReplyReply Direct Link To This Post Posted: 10 January 2010 at 5:32am
Looks good.  Is the 7mm Xmax of the PD a limiting factor here?

I'm currently doing something similar, but going for more compact (900h x 520w x 596d, INCLUDING a sealed box for internal power amp) and slightly lower extension to 40Hz single box, but do have to look at 9 to 10mm Xmax 12" drivers.  Ended up with a ported bandpass horn design.  Should be starting the build this week, hopefully test next weekend.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Centauri Quote  Post ReplyReply Direct Link To This Post Posted: 10 January 2010 at 5:43am
By the way, how did you sim the multiple cabinets?
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pfly View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote pfly Quote  Post ReplyReply Direct Link To This Post Posted: 10 January 2010 at 1:40pm
Like I said, I started designing this thing with PD and after I got it somehow together, I tried it with 6-7 different 12" drivers. Most of them seemed to not work in this thing, peaky and ugly response. Couple drivers did give something of a useful response but the only one that did better was 18sound 12NLW9300, but it costs 3-4 times the price of the PD. It gave about 1dB more sensitivity between 50-90hz, it would have 1mm more one way xmax and would have double the power rating.

Xmax @ 400 watts goes over 7mm around 37-44hz depending on how many cabs are used, also it is somewhere around 7,5mm around 55-60hz but I don't think that's too big problem

Now someone correct me if I have got this wrong:
When I sim one section horn in horn response, it has the option of using multiple cabs when looking at the frequency response, this option is unavailable when using multiple segments and / or ported back chamber. However, when simulating the single section horn and checking how it would work in multiples, the response graph shows similar behaviour as if I just changed half-space to quarter space and so on. I take it has something to do with the horn math horn resp is based on? So I've been exploiting this "option". I sim all my bass cabs in 2pi because I am not gonna fly them. Midbass cabs I usually sim in 4pi.

with bass cabs I work like this:

2pi = 1 cab on the floor
1pi = 2 cabs on the floor
0,5 pi = 4 cabs on the floor

The stack of eight I simulated by making a new project where I doubled the cross section areas, volumes and number of drivers, kind of making a double cab, then simulating it in 0,5pi
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rich_gale Quote  Post ReplyReply Direct Link To This Post Posted: 11 January 2010 at 12:26am
like it:)  have you made one yet?  would be interested to hear how smooth it sounds up to higher than 200hz.  maybe 250/300hz??   
REFLEX ALL THE WAY.... (however, im playing with horns again...) That ok Mister Valiant? :)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote login4 Quote  Post ReplyReply Direct Link To This Post Posted: 11 January 2010 at 2:29am
looks good, although all the ported horns i have sim'd have needed large Xmax
CELTIC SUBSONIC SOUND SYSTEMS
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Centauri Quote  Post ReplyReply Direct Link To This Post Posted: 11 January 2010 at 3:25am
Originally posted by pfly pfly wrote:

The stack of eight I simulated by making a new project where I doubled the cross section areas, volumes and number of drivers, kind of making a double cab, then simulating it in 0,5pi

Yeah, I was wondering how you did that.  Changing the pi loading setting is a good way to simulate multiple cabinets if the multi option is not available.

Originally posted by login4 login4 wrote:

looks good, although all the ported horns i have sim'd have needed large Xmax

Depends on how small you are trying to get the box, and how low you want to get - The smaller and lower, the greater the excursion required and the lower the efficiency.  Everything's a compromise - just have to pick the best compromises for the application.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote pfly Quote  Post ReplyReply Direct Link To This Post Posted: 11 January 2010 at 5:08pm
I do not think 7mm is "small" Xmax. Most more expensive 12" sub drivers today have Xmax somewhere between 8-11mm xmax. With rated power of 400 watts, Xmax exceeds in 55-60hz by about 0,5mm. That is if the simulation correlates with the real world. Also I suspect that with power compression taking the last 2dB out from the power, there will also be less excursion.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mykey Quote  Post ReplyReply Direct Link To This Post Posted: 11 January 2010 at 5:16pm
7mm is fine, it would seem some of the 'ICE' people are working their way over to PA, and don't realize how much air can be shifted from +- 8/9mm

  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote james folkes Quote  Post ReplyReply Direct Link To This Post Posted: 11 January 2010 at 5:36pm
looking very good, and as you say it is a nice easy build. i was expecting to hear mykey suggest putting a bend in the port so the port cannot "see" the back of the driver, that might yet be something that's worth doing (like in teunos' ported 15" horn).

james.
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