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12"+8"+1" Mid/High Plan

Printed From: Speakerplans.com
Category: Plans
Forum Name: New Projects Forum
Forum Description: Forum for new speakerplans projects, in memory of Tony Wilkes, 1953 - 2014
URL: https://forum.speakerplans.com/forum_posts.asp?TID=13902
Printed Date: 17 May 2022 at 12:57pm
Software Version: Web Wiz Forums 12.05 - http://www.webwizforums.com


Topic: 12"+8"+1" Mid/High Plan
Posted By: bmf2
Subject: 12"+8"+1" Mid/High Plan
Date Posted: 16 January 2008 at 3:29am
Been working some more on a previous mid/high idea and thought I'd get some opinions.
 
B&C 12PE32                 12"
Eminence Alph 8MRA     8"
Selenium D210TI           1" (crossed at 3.5K)
90 X 40 Rotatable Comp Horn
 
Plan on making a removable filler panel for the 8" to reduce the coverage angle when arrayed. Just plug in the panels and rotate the horn. Dispersion of the lower freq is somewhat of a compromise but shouldn't be as noticable in that range.
 
Heres the box
 


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You say it's too loud-I say your hearing is too good



Replies:
Posted By: Mark James
Date Posted: 16 January 2008 at 3:34am
one question.... why not use the 8pe21?????

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me so horny me love you long throw
horn loaded for her pleasure


Posted By: mylesound
Date Posted: 16 January 2008 at 3:35am
lol i was thinking about something like that.
but to make it simple i was going to use the 8" section from the Xtro
and do a simple reflex 15" with a 1" on top
wasnt sure if that was a good idea so it kinda died in my mind.
i think you have something going. almost like a compact solution to the Xtro.
how low do you think it will go?


Posted By: djstefanos
Date Posted: 16 January 2008 at 3:40am
how about making a skeleton. sort of like the JBL HLA touring series. Looking at that its a heck of a heavy cabinet and waste of space.


Posted By: Mark James
Date Posted: 16 January 2008 at 3:45am
nice idea though yeah, whats the crossover point between 12 and 8?
youve got to 3.5k with an 8mr????
fair play!!!
nice idea!


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me so horny me love you long throw
horn loaded for her pleasure


Posted By: bmf2
Date Posted: 16 January 2008 at 3:47am

The main reason for the alpha over the b&c is price. I can buy these alphas for $30! The 8pe21 will cost me right at $100. The second reason is the closed back simplifies construction.

I'm not sure how low it will play. The lower section is the same as a mt122. I need to get to 150hz so I'm not real confident of this part. I thought Super's 1 X 12" might fit this better. Maybe he could PM me the specs?Wink


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You say it's too loud-I say your hearing is too good


Posted By: bmf2
Date Posted: 16 January 2008 at 3:54am
djstefanos,
 
The mid/high cabinets we are using now  have two horns, an 8", and a 15" so I don't think the guys will make any complants about the weight.
 
 


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You say it's too loud-I say your hearing is too good


Posted By: mylesound
Date Posted: 16 January 2008 at 3:57am
if weight is not a problem why not just go for the xtro?
lol


Posted By: Mark James
Date Posted: 16 January 2008 at 4:24am
good point!!!
the mt122 12" should be fine down to 120hz


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me so horny me love you long throw
horn loaded for her pleasure


Posted By: bmf2
Date Posted: 16 January 2008 at 4:25am

Mark,

According to B&C the 12 will play all the way up to 2K smoothly. I have no intention of running it anywhere near that high. I will probably use some trial and error with an rta to find the best crossover point. The 8" starts to fall off right about where I want to cross it. It does have a dip at about 2K.



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You say it's too loud-I say your hearing is too good


Posted By: bmf2
Date Posted: 16 January 2008 at 4:26am
If the mt122 design is good down to 120hz I'll stick with this design as it will be simple to build.

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You say it's too loud-I say your hearing is too good


Posted By: Mark James
Date Posted: 16 January 2008 at 4:29am
mt121 isnt that easy but hey, how low can you get the 8" down to and still play up to 3khz???
might like to see the 8" plans lol.....


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me so horny me love you long throw
horn loaded for her pleasure


Posted By: bmf2
Date Posted: 16 January 2008 at 4:36am
Just a sidenote:
 
While playing last Sat. I lost one of my mid/highs 3 songs into a set. The band took a break as soon as possible and I started backtracing. I ended up all the way back to the cabinet itself. I pulled the jack plate off to find the very complicated crossover/zobel had vibrated loose and ripped the wires off of everything as it fell to the bottom of the cabinet. Sweat is building because we had just took our other cabinets out of the trailer a couple days earlier. I went to emergency repair method one. Solder the 15" back to one input jack and the top horn back to the other. Plugged in the mid line and high line and cringed the rest of the night. Censored
But I did manage to get the band back up in ten minutes.


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You say it's too loud-I say your hearing is too good


Posted By: Jake_Fielder
Date Posted: 16 January 2008 at 8:59am

Im really interested in how this design goes, I thought it was more conventional to go for a 6" driver with a 12" and 1", any reason for going with an 8"??

Im getting dejavu, Have you started a thread with tis design in already, and tony told you to line up the drivers.....? or am i completely insane?!
 
EDIT: Haha here it is ( http://www.speakerplans.com/forum/forum_posts.asp?TID=13202&PN=2 - BAM! ) how come you dropped this design?


Posted By: pooju
Date Posted: 16 January 2008 at 12:58pm
How have you designed the 8 flare on the Bmf2 is it a scaled mt? have you gone for the 45x45 flare - if thats what it is - to match the first section of the the 8? -keep us updated!
unlucky on the rattling xover!


Posted By: bmf2
Date Posted: 16 January 2008 at 1:07pm

I picked the 8" because of the 101 spl. The Eminence LA6-CBMR 6-1/2" I was thinking of using is only 97. I would need two of them to keep up and they aren't available in a 4 ohm which would cause me problems in wiring the cab up (two 4 ohm series for 8 ohm).

The 8" flare is designed to have two patterns. The first being a wide pattern and when the inserts are installed being a 40 degree. Both where compromised a little to make it work.

Yes Jake this is a variation of the old design. I found a source for the High flare I wanted to use and got exact dims. for it so I could get a little further in the box design.


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You say it's too loud-I say your hearing is too good


Posted By: Jake_Fielder
Date Posted: 16 January 2008 at 2:05pm
Well it seems like a good idea, im especially interested as im goin to be building some midtops soon. as pooju says: keep us updated
 
Cheers


Posted By: tb_mike
Date Posted: 18 January 2008 at 1:36am
Originally posted by bmf2 bmf2 wrote:

I picked the 8" because of the 101 spl. The Eminence LA6-CBMR 6-1/2" I was thinking of using is only 97. I would need two of them to keep up and they aren't available in a 4 ohm which would cause me problems in wiring the cab up (two 4 ohm series for 8 ohm).

The 8" flare is designed to have two patterns. The first being a wide pattern and when the inserts are installed being a 40 degree. Both where compromised a little to make it work.

Yes Jake this is a variation of the old design. I found a source for the High flare I wanted to use and got exact dims. for it so I could get a little further in the box design.

You realise that those sensitivity measurements were made on a standard enclosure or baffle, so on a horn it doesnt count.

Also youl notice that the 6" will have almost half the cone area of the 8"- thus giving the +3dB.

Remember that the highest frequencies are effected by teh first part of the horn.
So from what I can see from your diagram,the dispersion will be more narrower in the upper region of the midhorn,where it will cross over to the HF horn.



Posted By: ArthurG
Date Posted: 18 January 2008 at 3:27pm
first tb_mike is right and 2nd I don't want to be too rude but this Eminence 8" sounds like crap above 2k... the extension of response frequency is because of mechanical resonance. in other words, it produces more distortion than anything else... that's why it's so cheap...


Posted By: Maffy Dmg
Date Posted: 08 January 2022 at 4:51pm
Good evening my name is Alex, I would like more technical specifications on this project because I would be interested in building it thanks.


Posted By: djeddie
Date Posted: 17 January 2022 at 8:37pm
Maybe out of luck there Alex, the last time the OP was on this site was 13 years ago!

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Chas n Dave : it's like Drum and Bass but with beards.             E=mc² ±3dB


Posted By: Maffy Dmg
Date Posted: 19 January 2022 at 3:36pm
What a bundle, thank you



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