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2x15" Bifurcated Horn
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ceharden View Drop Down
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Joined: 05 June 2005
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Points: 8348 		Post Options Post Options   Thanks (0) Thanks(0)   Quote ceharden Quote  Post ReplyReply Direct Link To This Post Topic: 2x15" Bifurcated Horn
    Posted: 05 August 2006 at 4:00pm
 Ok, I've taken one step forwards on the bass horn designs in that I've bought one driver (well, waiting for it to arrive actually), a PD 15SB40.  If it does what PD claims, it's designed exactly for cabs like this.  High BL, low Qts and it's lightweight .  Neo magnet also allows you to reverse mount the driver nicely.  Now I could go for something conventional-ish like this:
 
But I think it looks nicer and more compact like this:
 
 
Now the ideal driver I've found is the 18Sound 15ND930.  For which the response for two of these babies together would be:
 
 
Rather nice eh?  The PD driver has a little more ripple and slightly less efficiency/low extension.  Probably not that much difference in practice and the PD is cheaper and more available.
 
Before you pull me up on technicalities of the flare, the simulation and the drawing don't exactly agree at the moment but it should be possible with tweaking of panels.
 
James, I'm sure you'll have thoughts on bifurcation.  Plan is to try a single and if the driver mounting etc works then I'll try a double bifurcated.
 
Might have to wait until after all of the festivals tho, working three in four weeks starting next week.....


Edited by ceharden - 05 August 2006 at 4:03pm
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james folkes View Drop Down
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Points: 3061 		Post Options Post Options   Thanks (0) Thanks(0)   Quote james folkes Quote  Post ReplyReply Direct Link To This Post Posted: 05 August 2006 at 9:16pm
Originally posted by ceharden ceharden wrote:

James, I'm sure you'll have thoughts on bifurcation.

it's funny you should mention the b word... i've got plenty of pictures of the ways the meeting throats have been tackled on a variety of 215 and 218 horns of this nature, pm me your email and i'll send you some scans.

that looks grand though, neos are a nice choice for weight considerations. go trapezoidal if you're feeling really adventurous and you can chop out your paralell walls for a reduced honk. i tried (and still am trying) to make that layout tune for 100~400 from two 12"s (still plodding on with the mid top project, prototyping for someone with sn-bs), but the motor makes it really difficult to tune the front chamber volume in the desired way.

james.
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Mircea Bartic View Drop Down
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Points: 2116 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Mircea Bartic Quote  Post ReplyReply Direct Link To This Post Posted: 06 August 2006 at 3:28am
James, there are new developments on the mid top battlefield with a prototype due to be started in about 3 weeks
general manager & head designer at nexus-acoustics research
http://www.forum.poweraudio.ro - Romania's biggest ProAudio forum.

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ceharden View Drop Down
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Points: 8348 		Post Options Post Options   Thanks (0) Thanks(0)   Quote ceharden Quote  Post ReplyReply Direct Link To This Post Posted: 06 August 2006 at 5:13am
Cheers James, will PM with email.  I did consider trapezoidal, but I want to be able to lie them down on their side as well as stand on-end so I probably won't for the time being.  Worth considering tho.  Starting to wish I'd ordered two 15" drivers so I can go straight to prototyping the twin.  Don't think there's any point messing around with singles.

I looked at that twin 12" arrangement, I reckon if anything it'll be the 90deg+ fold just after the throat which will limit the top end.  Interestingly it's the only type of cab I think my 12NDL76's are really suited for.  Might be easier to work with due to the more compact magnet compared with the P-Audios.

Look forward to seeing some movement on the mid-top project.  I'm afraid I'm going for something a little more conventional now.....
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gingerbiscuit69 View Drop Down
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Points: 2540 		Post Options Post Options   Thanks (0) Thanks(0)   Quote gingerbiscuit69 Quote  Post ReplyReply Direct Link To This Post Posted: 07 August 2006 at 3:42pm
for all the silly people like me here .. wtf is 'bifurcation'!?!?
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Mark James View Drop Down
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Points: 4338 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Mark James Quote  Post ReplyReply Direct Link To This Post Posted: 07 August 2006 at 4:16pm
hang on @james
did you say a mid bass horn to use sn12b drivers thatl play nice  100<250hz or a little heigher?
let me know if plans surface!
any idea on the frontal measure meents [ie foot print and height]
cheers
markk
bpm project part two in pregress !!!
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james folkes View Drop Down
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@ gingerbiscuit:

bi·fur·ca·tion (b?'f?r-k?'sh?n)
n.
A division into two branches; a forking.

@markk: you will be welcome to the plans etc when formalised. i'm doing a prototype now though because there is a good chance it will be pony. frontal is roughly 500 wide, 800 high, possibly slightly taller.

james.
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Mark James View Drop Down
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Joined: 15 January 2006
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Points: 4338 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Mark James Quote  Post ReplyReply Direct Link To This Post Posted: 08 August 2006 at 9:44am
nice!!! exactly what i might be after.......
and then i can get silly with the mids.
btw that bifurcated design looks like it could make a rather atractive looking box.
also the plot looks nice as well,
bpm project part two in pregress !!!
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kevinmcdonough View Drop Down
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Points: 2006 		Post Options Post Options   Thanks (0) Thanks(0)   Quote kevinmcdonough Quote  Post ReplyReply Direct Link To This Post Posted: 09 February 2012 at 3:48pm
hey

lol digging up a 5+ year old thread is always fun!

As ive mentioned in a couple of threads this is exactly the kind of thing i'm thinking of doing with 18" drivers, either ported or possibly tapped horns. James if you still have those 15" and 18" throat pics i'd love to see them.

k


Edited by kevinmcdonough - 09 February 2012 at 3:49pm
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