Oh Boy, we have Martin involved now!! Thanks guys,
I think that this project might be quite popular, also we'll get some other big varients such as Paul's.
There are tons of concentric pro 12" driver/horn tweeters out there. The right combo could be very impressive.
Even the wrong combo could be some very impressive party speakers!
I think that this project might be quite popular, also we'll get some other big varients such as Paul's.
There are tons of concentric pro 12" driver/horn tweeters out there. The right combo could be very impressive.
Even the wrong combo could be some very impressive party speakers!
Since there are no big corrections, maybe in your spare time 
you could do a response plot of this size..?
Those little squares in the section at the end of the flare are 2x2's to help brace a little. Admittedly at this size it would be best to have the whole thing thicker, but expensive. Punkr could add another layer on the sides later if he loves them, to make them even better- and REALLY heavy! I am looking into using the scraps to at least add some thickness at the very top.
So damping on both sides of the internal baffle/divider? How thick? What material?
you could do a response plot of this size..? Those little squares in the section at the end of the flare are 2x2's to help brace a little. Admittedly at this size it would be best to have the whole thing thicker, but expensive. Punkr could add another layer on the sides later if he loves them, to make them even better- and REALLY heavy! I am looking into using the scraps to at least add some thickness at the very top.
So damping on both sides of the internal baffle/divider? How thick? What material?
not sure but...
Beyma also have some nice 12 inch coax drivers. These I believe are less expensive than the B&C units but will still be more expensive than the Eminence LAT. Remember though that the LAT is a 12 inch wide range with a whizzer cone as opposed to a Tannoy style dual concentric two way with a comp mid/tweeter. More money yes but a lot more speaker and in the long run not all that much more money. At least people reading should be aware of possible options. With what you could sell a set of BIB's with LAT's in them you could afford the B&C or Beyma drivers for round two. Have a look at the Beyma 12XC30 which ought to work well in a BIB. Probably double the money of a LAT but more than twice the driver and don't forget LAT's will need a tweeter to help out the top end so there is additional cost/time to consider there as well. Regards Moray James.
Beyma also have some nice 12 inch coax drivers. These I believe are less expensive than the B&C units but will still be more expensive than the Eminence LAT. Remember though that the LAT is a 12 inch wide range with a whizzer cone as opposed to a Tannoy style dual concentric two way with a comp mid/tweeter. More money yes but a lot more speaker and in the long run not all that much more money. At least people reading should be aware of possible options. With what you could sell a set of BIB's with LAT's in them you could afford the B&C or Beyma drivers for round two. Have a look at the Beyma 12XC30 which ought to work well in a BIB. Probably double the money of a LAT but more than twice the driver and don't forget LAT's will need a tweeter to help out the top end so there is additional cost/time to consider there as well. Regards Moray James.
The Seleniums don't seem to be available from PArts Express, BUT you reminded me that others might sell them if they still import that model . They come with a built in crossover, so that gets taken care of, and they have a concentric tweeter. so they are a deal....Still a LOT more than the Eminence LTA drivers which dio have a good reputation.
PAudio make them too- actually almost every pro component maker makes a 12" concentric with a tweeter so it is going to be a very long list if everyone starts suggesting drivers.
BUT it is hard to beat the value of the Eminence 12LTA. It has a low resonant frequency of 45 hz which helps with the bass.
One cool think is that it will look like the BIB's with a Fostex (which have whizzer cones) only blown up huge!!
I don't think anyone should assume that they can resell speakers they make for profit or even to get their money back. - especially something this size. Heck,considering how little the 12 LTA's cost, he can later try other drivers if he wants at very little loss. The old LTA model was known to sound good, and was the basis of the Hammer home speaker, so I don't think people should worry about it and second guess the decision.
Go for it Punkrockr!! You have what you need, the drawings plus a million questions and you're done!!
5 sheets of MDF for about $125 or 5 sheets of that imported birch I mentioned for $200. Plus a pair of 12 LTA drivers for about $120
After you finish the cabinets I suggest you get the Fostex FT17 tweeters for them. They only cost $70 for a pair, and they will be crossed over really high, so hopefully the crossover won't be a problem.. Also remember I have a pair at a deal if you get the speakers done..
You must have some questions about the box drawings ..or did
I do that good a job? One nice thing about 12" drivers is that is is pretty easy to get into the box to add damping fiber or wire the tweeters. Also the top being completely open is helpful too!
PAudio make them too- actually almost every pro component maker makes a 12" concentric with a tweeter so it is going to be a very long list if everyone starts suggesting drivers.
BUT it is hard to beat the value of the Eminence 12LTA. It has a low resonant frequency of 45 hz which helps with the bass.
One cool think is that it will look like the BIB's with a Fostex (which have whizzer cones) only blown up huge!!
I don't think anyone should assume that they can resell speakers they make for profit or even to get their money back. - especially something this size. Heck,considering how little the 12 LTA's cost, he can later try other drivers if he wants at very little loss. The old LTA model was known to sound good, and was the basis of the Hammer home speaker, so I don't think people should worry about it and second guess the decision.
Go for it Punkrockr!! You have what you need, the drawings plus a million questions and you're done!!
5 sheets of MDF for about $125 or 5 sheets of that imported birch I mentioned for $200. Plus a pair of 12 LTA drivers for about $120
After you finish the cabinets I suggest you get the Fostex FT17 tweeters for them. They only cost $70 for a pair, and they will be crossed over really high, so hopefully the crossover won't be a problem.. Also remember I have a pair at a deal if you get the speakers done..
You must have some questions about the box drawings ..or did
I do that good a job? One nice thing about 12" drivers is that is is pretty easy to get into the box to add damping fiber or wire the tweeters. Also the top being completely open is helpful too!
B.A.F. equals...
Bonded Acetate Fiber. This is much like polyester batting only it is stiffer and the fibers are thicker than Polyester. In B.A.F. the fiber tangle is "bonded" in other words everywhere two fibers touch they are stuck or bonded together. Kind of like an irregular celular foam (open) but with non regular size open sections.
I always assumed that B.A.F. like open cell foam damped via air resistance while loose fibers had most of their damping through heat loss due to friction of the fibers. Not sure if I am right about that but it make sense to me. Regards Moray James.
Bonded Acetate Fiber. This is much like polyester batting only it is stiffer and the fibers are thicker than Polyester. In B.A.F. the fiber tangle is "bonded" in other words everywhere two fibers touch they are stuck or bonded together. Kind of like an irregular celular foam (open) but with non regular size open sections.
I always assumed that B.A.F. like open cell foam damped via air resistance while loose fibers had most of their damping through heat loss due to friction of the fibers. Not sure if I am right about that but it make sense to me. Regards Moray James.
woah!
you guys have really been misbehaving.... seriously. this?
I cannot allow it.
I forget to check all the forums for a bit and THIS is where the full range hoodlums end up.
designing crazy PA systems.
well, for what it matters, I think that I will build one...
HAHAHAHAHA
or at least I will suggest this design to a friend. it will need a truck to move, but he wants to do DJ sets - turntablism. deep powerful bass is a must. and all he has is an old yamaha receiver.
I have been interested by this big 12 incher for some time. Ill probably go with the ft17h tweeter as well.
all I can get out here is 5 by 5 sheets of imported birch. its heavy stuff, but really all that is suitable in my opinion, especially for PA systems, which see alot of abuse.
to make it six feet tall will require some doubling at the mouth area. this was to be expected anyways.
I am too swamped with schoolwork right now to do much math, but if someone comes up with some sort of a cutsheet using dimentions in the middle of biggest and just big enough, then I will be sure to write your name on the bottom of the speakers as credit.
you guys have really been misbehaving.... seriously. this?
I cannot allow it.
I forget to check all the forums for a bit and THIS is where the full range hoodlums end up.
designing crazy PA systems.
well, for what it matters, I think that I will build one...
HAHAHAHAHA
or at least I will suggest this design to a friend. it will need a truck to move, but he wants to do DJ sets - turntablism. deep powerful bass is a must. and all he has is an old yamaha receiver.
I have been interested by this big 12 incher for some time. Ill probably go with the ft17h tweeter as well.
all I can get out here is 5 by 5 sheets of imported birch. its heavy stuff, but really all that is suitable in my opinion, especially for PA systems, which see alot of abuse.
to make it six feet tall will require some doubling at the mouth area. this was to be expected anyways.
I am too swamped with schoolwork right now to do much math, but if someone comes up with some sort of a cutsheet using dimentions in the middle of biggest and just big enough, then I will be sure to write your name on the bottom of the speakers as credit.
Forgot to mention:
For cross bracing "closet pole" works well. The stuff you use in a closet to hang clothes on. Usually hardwood. Easy to get and cheap at home improvement stores and the like. And it's round!
I see that you have put in a couple of 2x2s for bracing. Either that or poles, but maybe more of them. The internal baffle will help a lot, but the sides of this are really big.
For cross bracing "closet pole" works well. The stuff you use in a closet to hang clothes on. Usually hardwood. Easy to get and cheap at home improvement stores and the like. And it's round!
I see that you have put in a couple of 2x2s for bracing. Either that or poles, but maybe more of them. The internal baffle will help a lot, but the sides of this are really big.
why not go easier?
I think the cheapest meaningfull configuration is eminence delta 15 together with selenium driver D210Ti; anything less is not worth the work on enclosure
xover schematics (proven) - http://www.prodance.cz/download/EM151_vyhybka.pdf
box - http://www.prodance.cz/download/EM151.pdf
I think the cheapest meaningfull configuration is eminence delta 15 together with selenium driver D210Ti; anything less is not worth the work on enclosure
xover schematics (proven) - http://www.prodance.cz/download/EM151_vyhybka.pdf
box - http://www.prodance.cz/download/EM151.pdf
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