bigdnfay Posted May 17, 2005 Share Posted May 17, 2005 Hi All, I was thinking about lining the inside roof of the doghouse in the jubilee clones. This is an acoustic wall carpet and it has a very good damping factor and is only 3/16 thick. It has a sprayed-on latex backing, so it can be glued or stapled. I hung this in the pilots briefing theater on Pope Airforce Base and it completely cut out all the echo in the room. My question is...do you all think this will be to much damping or should I try something less aggressive? Big D Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted May 17, 2005 Share Posted May 17, 2005 Maybe Tony Reed can chime in here. I think he's had a for real look inside a Jubilee doghouse. Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted May 17, 2005 Share Posted May 17, 2005 what color were you thinking , will the Dog like it ..?? Oh, never mind .... Quote Link to comment Share on other sites More sharing options...
D-MAN Posted May 17, 2005 Share Posted May 17, 2005 It is not going to DAMPEN much, it is far too thin to absorb any useful wavelengths in the bass bin. If you want to lessen REFLECTIONS that's different, and you should put it at the BOTTOM of the bin. The top will not do very much IME. Triangular-shaped back chambers only "need" absorptive material on the bottom, according to "How to Build Speaker Enclosures", Badmaeff and Davis, 1978. I am doing that myself in my horns which BTW are probably the closest things to being Jubilees without being Jubilees, so alot is related more to yours than with Khorns. Bottom only, fiberglass. Tried more, but ended up taking most of it out. use FIBERGLASS or substitute instead; don't know if you need to even do the top once in the bottom. I found that too much material "muddies" the sound up, so I went with about 1 inch overall in the bottom only. DM Quote Link to comment Share on other sites More sharing options...
bigdnfay Posted May 17, 2005 Author Share Posted May 17, 2005 Sorry about my terminology.. I was thinking about reflections.Now the Jubilee has a hatch on the top and bottom. So your saying I only need it just inside the bottom hatch...Right? Big D Quote Link to comment Share on other sites More sharing options...
D-MAN Posted May 17, 2005 Share Posted May 17, 2005 That's what they say. I find that it is enough. But I only have one hatch on the top of the cab, which makes the use of fiberglass less of an issue for me. Additionally, I did try the behind-the-woofer insulation, but again, found it to muddy things up too much, so I ended up taking it out. {edit} also, the difference between the top and bottom has less meaning to you having access panels on each. So I suppose that it won't matter at all which one you "insulate" except for ease of access considerations. DM Quote Link to comment Share on other sites More sharing options...
bigdnfay Posted May 17, 2005 Author Share Posted May 17, 2005 D-Man, How about posting another pic of your cabs. Big D Quote Link to comment Share on other sites More sharing options...
D-MAN Posted May 17, 2005 Share Posted May 17, 2005 It's an old picture, and DON'T use this much insulation... It is not as shown now, I removed the insulation that is shown... DM Quote Link to comment Share on other sites More sharing options...
D-MAN Posted May 17, 2005 Share Posted May 17, 2005 Here's the bass bin. Quote Link to comment Share on other sites More sharing options...
bigdnfay Posted May 17, 2005 Author Share Posted May 17, 2005 Ah So...What are you using on the top-end? Big D Quote Link to comment Share on other sites More sharing options...
D-MAN Posted May 17, 2005 Share Posted May 17, 2005 JBL 2404H tweeters Selenium D-305 phenolic 2" drivers on P-Audio 90x40" 400Hz fc horns (17.5x10.5x9.5") But you're going to need Extreme Slope networks to get a nice cutoff between the bass bins and the midranges, and THAT's the MOST expensive part of the whole thing! I crossed over at 600Hz and 5800Hz, and couldn't be happier now. The ALK-A's or assuming standard Khorn crossovers (6db) did not have a steep enough slope. DM Quote Link to comment Share on other sites More sharing options...
bigdnfay Posted May 17, 2005 Author Share Posted May 17, 2005 I'm using AL's ES700 2-way network. It works well with the bass bin. Just need a better top end driver. Big D Quote Link to comment Share on other sites More sharing options...
D-MAN Posted May 17, 2005 Share Posted May 17, 2005 There you go! You're already halfway home. If you want to go 3-way, the JBL's are the cat's meow! But spendy... I like the Seleniums as a brand, reasonably priced, and they are hard to blow up, I've clipped my MC300 into them without damage. I would recommend two things, 1) don't go below a 90x40 dispersion pattern on your upper horns 2) go with a 2" driver and horn throat as they are more numerous and better competition means lower prices? One can only hope. Actually the Goldwood (chinese) have a 500Hz tractrix knockoff of my P-Audio horns for 49.95 each vs. the $105 each that I paid. I would not hesitate to try them next time as I no longer am limited to 400Hz fc. DM Quote Link to comment Share on other sites More sharing options...
bigdnfay Posted May 17, 2005 Author Share Posted May 17, 2005 I'd like to stay 2-way if at all possible. The altec 807's I'm using now drop like a stone after 12khz. I'd like to get it up to at least 15khz. I've been looking at the jbl 2426. Even though the specs say they go up to 20khz they start dropping around 15khz which is about right for me. Your right JBL is spendy. May have to go one at a time. Big D Quote Link to comment Share on other sites More sharing options...
D-MAN Posted May 18, 2005 Share Posted May 18, 2005 The JBL tweeters are rated to 19K +/- 3db, suprizingly low for the price, seems to me. But if you go 2-way, you will be stuck with using an EQ. 3-ways can run pretty nicely without an EQ. And that will save you money in the long run. {edit} after thinking about it, you will probably have to go with an EQ regardless. The issue of the output sensitivity of the Jubilee bass horn is what 109db vs. the 104db for the Khorn that we are all used to. So the top end has to crank it twice as loud as the same Khorn arrangement, and doing that without harshness is going to be a pain, I should think. DM Quote Link to comment Share on other sites More sharing options...
D-MAN Posted May 18, 2005 Share Posted May 18, 2005 I've been thinking more about this, and recognising that the Jubilee bass output is much higher than the Khorn (104db), the upper frequency horns have to at least match the rated 109db of the Jubilee as much as possible. That means that the upper horn driver or drivers should be at least 109db, and probably should be even higher (113db) so they can be attenuated for at least some control. This limits the available single drivers that could work, however, that being the case, let's consider DOUBLING up on cheaper drivers, which accomplishes the same thing. Or even 2-smaller (i.e., 1" throat) drivers mounted to the same single large (2" throat) horn in a sum-fashion. Could work and be even fairly easy, and certainly cheaper... Definitely would mean a 2" throat horn. DM Quote Link to comment Share on other sites More sharing options...
Marvel Posted May 18, 2005 Share Posted May 18, 2005 Big D, You might remember me asking about the JBL 2426H. JBL used/uses this one inch driver in some two ways they make, I can be crossed at 500Hz, with a derating to 20watts. Although still in production, and expensive, they can be had for under $200 each. PE sells them, so you could look up the specs on them. If you are crossing at 700Hz with an ESN, they should be fine. Marvel Quote Link to comment Share on other sites More sharing options...
ZAKO Posted May 18, 2005 Share Posted May 18, 2005 The JBL 2426 drops like a stone after 15K. IN my field we call it a mid range driver with a top end zipp. Quote Link to comment Share on other sites More sharing options...
Marvel Posted May 19, 2005 Share Posted May 19, 2005 Maron, I fully understand that. But a lot of people seem to be pretty happy using that driver in a two way. I am going to try it on something as well, and may have to resort to a three way. Marvel Quote Link to comment Share on other sites More sharing options...
ZAKO Posted May 19, 2005 Share Posted May 19, 2005 Marvel....I have a pair of JBL LE85 drivers with 2426 diafhrams. I like them very mutch & some times use them for tweeters crossing over 2K & up. They give good dynamic slam. Its amazing even at my advanced decrepid age I still hear the 2426 lacking at the extreem high frequencies. But Im not complining, In its bandwidth its very pleasing. Quote Link to comment Share on other sites More sharing options...
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