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A midrange horn project - opinions and proposals |
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_djk_
Old Croc
Joined: 23 November 2004 Location: United States Status: Offline Points: 5992 |
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Posted: 03 September 2008 at 6:40am |
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"is the horn 'extended' by the foam, or does it line the horn? And is it open or closed cell? I can't tell, sorry. "
The foam is 30-PPI open cell and there is a solid wall of the horn behind it.
"No, djk designs his horns.
And...those mids are massive " About 48" wide. They had a space frame (like the newer JBL HLA rigs), so they weren't heavy, just big.
The first pair of those I built started out with dual 15" drivers, this was OK as I was 4-way with phenolic compression drivers. Later, I changed them to 12s so they could go high enough to go 3-way with metal compression drivers. Edited by _djk_ - 03 September 2008 at 6:49am |
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djk
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technofreak
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Joined: 24 August 2008 Location: Estonia Status: Offline Points: 74 |
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Posted: 03 September 2008 at 8:53am |
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OK, seems like my ideas would work, right? So, after I get my salary, I´ll start building ASAP and post some pics here too.
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tb_mike
Old Croc
Joined: 01 October 2004 Location: New Zealand Status: Offline Points: 2744 |
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Posted: 03 September 2008 at 8:58pm |
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technofreak - it looks as if youve read the good papers and the best thing to do now is to build :-D! Did you see JBL CMCD(?) technote regarding direct radiator vs 6" cone mid.
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doober
Young Croc
Joined: 03 January 2006 Location: Cornwall UK Status: Offline Points: 1123 |
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Posted: 03 September 2008 at 10:08pm |
Can someone post the link to this article? I'm sure I saw it recently but I can't find it now. Kieran |
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Blahblahblah
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Deadbeat
Old Croc
Joined: 12 March 2008 Location: Singularity Status: Offline Points: 3167 |
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Posted: 04 September 2008 at 8:43am |
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Away on extended leave.
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doober
Young Croc
Joined: 03 January 2006 Location: Cornwall UK Status: Offline Points: 1123 |
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Posted: 04 September 2008 at 4:03pm |
Thanks Deadbeat, that'll keep me entertained this evening. |
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technofreak
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Joined: 24 August 2008 Location: Estonia Status: Offline Points: 74 |
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Posted: 25 September 2008 at 6:37pm |
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Hi all,
Due to the economy going south here I have suspended the horn project (this would have cost me ~200€ for materials and carpenter, since I don't have tools or room for such things) for time being. But I certainly WILL build them one day! For now I put the Alphas in small sealed boxes and called it a day. With those old double-8" they make great compact DJ monitors, micro rig for house parties and very loud hi-fi speakers - played the system at full blast yesterday and that was ridiculous in my 20 sq. meters room, I actually started to feel bass with my hair! The amp is 200W/ch at 4 ohms. Here are some pics of the stuff. I used a cheap 2€ computer mic to get some idea of the freq. response - pretty flat from 50 Hz to 10 kHz, starts to roll off after that. I don't know what to blame more - the mic or the piezo tweeter, probably both are equally quilty. Slight EQ-ing of the top octave is required. The piezos are those 1€ things, slightly modified - added some wadding behind the diafragm, of course proper filter is applied (8,2 ohm 10W resistor across terminals, 1,5 uF cap in series and another 8,2 ohm 10 W resistor in series with all this). No harshness at 5 kHz. Alpha is rolled off at 5,8 kHz w/ 0,22 mH inductor and high-passed w/ 68 uF cap. Eight-inchers are low-passed w/ 3 mH inductor. It all works pretty well, though using 2. order x-overs would be better - the excursion of Alphas gets quite high, although doesn't exceed X-max. I deliberately left so much room around the three sides of piezo - so I can fit some smaller proper HF horns if I wanted to. |
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tommysb
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Joined: 24 April 2006 Location: Finland Status: Offline Points: 1036 |
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Posted: 25 September 2008 at 11:54pm |
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Good to see. I love your Burberry Computer chair, and huge vodka bottle under the desk! Are all women in Estonia as beautiful as I've been lead to believe?
Tom |
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technofreak
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Joined: 24 August 2008 Location: Estonia Status: Offline Points: 74 |
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Posted: 26 September 2008 at 11:37am |
This chair is comfortable as hell . The vodka bottle wasn't emptied by me or my friends, we found it in a forest during a hike. No idea why we carried it all the way, it was empty, you know Must be crazy green thinking people... And yes, women here are really beautiful![]() |
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