lar418 Posted September 21, 2005 Share Posted September 21, 2005 JC, What drivers are you modeling? I used the Eminence Beta-8 as a midrange in a high-efficiency system for a friend a while back with pretty good results. It was a little bright sounding. We also tried an 8" Pioneer full range (B20FU20-51FW) and it was smoother, but not a dynamic. If you wanted a simple solution you could try the Eminence Beta-8cx and used there APT3 super-tweeter and pxb2-3k5 crossover. I've never heard this speaker though. Either driver should go down to 80 to 100 hz, which should be ok if you are using a bass management system. Quote Link to comment Share on other sites More sharing options...
jwc Posted September 21, 2005 Share Posted September 21, 2005 You are thinking like me. Yes that 8 inch woofer in the above plot is the Beta 8. It has good T/S for what I am trying to accomplish. Unfortunately, it is not shielded. The reps at partsexpress tell me I would be very unhappy with these Beta 8's and think I would be happer with there Dayton drivers which are shielded. I would have to used those bucking magnets you speak of on the betas. I would think this could change the T/S parameters. Not sure. The Dayton woofers are not nearly as efficient. Were you able to get the Betas very "low"? Quote Link to comment Share on other sites More sharing options...
lar418 Posted September 21, 2005 Share Posted September 21, 2005 JC, I fully understand your dilemma. With most high efficiency speakers you give up bandwidth and smaller drivers like the Beta-8's just don't go that low in frequency. Now throw in shielding and it gets tougher. Have you considered a Fostex driver? Madisound carries the Fostex FE207E (8" shielded full range driver with spl of 95 db) or the Fostex FE167E (6.5" shielded full range driver with spl of 94 db). Both should go down to 65 hz in a vented cabinet. Madisound has two suggested vented cabinets for each driver. These can also be used in a back loaded horn, but they get large. They are priced at $86.50 and $63.25 each, respectively. Since these are full range drivers, all you would have to do is add a super-tweeter with a simple cap in series. The power handling and x-max is better on the 8" unit, so that might be the driver of choice. Two of the FE207E's would require a 70 liter vented cabinet and two of the FE167E's would require a 30 liter vented cabinet. With either speaker, you might need to use the bass management system in your processor to roll off the bass, since very low bass might overdrive these. The people at Madisound are very helpful. Just a thought! Quote Link to comment Share on other sites More sharing options...
jwc Posted September 21, 2005 Share Posted September 21, 2005 Great info. Don't know why I haven't checked them out yet. Quote Link to comment Share on other sites More sharing options...
michael hurd Posted September 22, 2005 Share Posted September 22, 2005 How about the neodymium magnet Deltalite series from Eminence? They would have very little stray magnetic field due to the type of magnetic material. You have Win-ISD? Model 2 x Eminence Deltalite 2510 in a 4.5 cubic foot box, tuned to 50 hz. Excursion limited spl is 115 db from 55 hz and up with two, and 30 watts to each driver. More power will cause compression, due the woofers exceeding x-max. I modeled this with a voice coil temperature rise of 100F, as temperature rises, the response changes quite a bit. Try modeling it for yourself. If you substituted the Deltalite 2512 in a slightly bigger box, you could pickup a couple of extra db, but have worse characteristics ( dispersion + comb filtering ). Quote Link to comment Share on other sites More sharing options...
michael hurd Posted September 22, 2005 Share Posted September 22, 2005 Not to poo-poo on the fostex suggestion, but I just modeled it, the 8" shielded unit (FE 207E ) that was mentioned has a 1.5 mm xmax. This results in a dismal cap on the output ability. ( modelled 2 drivers ) In a tiny 1.2 cubic foot box, tuned to 55 hz, this results in an -3db point of 63 hz. The excursion limited power handling results in a maximum of 7 watts each, and an output ability of 104 db at 80 hz and up before the x-max is exceeded. At 63 hz, a maximum spl of 102.44 db is possible. Yawn. Certainly not enough to keep up to the dbb cornscalas @ 107 db/w/m. Quote Link to comment Share on other sites More sharing options...
dragonfyr Posted September 22, 2005 Share Posted September 22, 2005 JW, I think you're making this far too complicated! Just build another Cornscala! Besides its the right height to place a TV atop, and placing a thin sheet of conductive material that is grounded between the speaker top and the TV (assuming nothing conductive makes contact) for EMF isolation will take care of the degaussing issue with the TV. Face it, you know you want to do this! And you already know how! So.......[] Quote Link to comment Share on other sites More sharing options...
jwc Posted September 22, 2005 Share Posted September 22, 2005 JW, I think you're making this far too complicated! Just build another Cornscala! Besides its the right height to place a TV atop, and placing a thin sheet of conductive material that is grounded between the speaker top and the TV (assuming nothing conductive makes contact) for EMF isolation will take care of the degaussing issue with the TV. Face it, you know you want to do this! And you already know how! So.......[] Yes it is complicated. I can't fit a Cornscala or a CS-dbb in my tv cabinet. I WISH it were that simple. Bad thing is, once I build this thing my wife will probably want a new house and then i will no londer have the size limitation issue. My room is big but poor options for a center. I don't want to drop a heresy in there. M. Hurd. I will try the driver you mentioned tonight in the software. Quote Link to comment Share on other sites More sharing options...
DrWho Posted September 22, 2005 Share Posted September 22, 2005 You could totally fit a cornwall in there if you would simply get rid of the TV! Then all you would need to do is upgrade to a front projection system and get yourself a nice acoustically transparent screen that spans your entire front wall - ok a bit extreme but you could whittle this down a bit to something feasible. Quote Link to comment Share on other sites More sharing options...
dragonfyr Posted September 22, 2005 Share Posted September 22, 2005 ...Or you could simply drop the pedestal/stage floor and extend it downward! How do you like our ingenious ideas for redesigning your house!?[][] Quote Link to comment Share on other sites More sharing options...
dhsettim Posted September 23, 2005 Author Share Posted September 23, 2005 Thanks everyone, especially JW Cullison. It seemed like a good idea as it was easily reversible but it seems that it won't work. Ok, onto the next idea. tim Quote Link to comment Share on other sites More sharing options...
jwc Posted September 24, 2005 Share Posted September 24, 2005 Thanks everyone, especially JW Cullison. It seemed like a good idea as it was easily reversible but it seems that it won't work. Ok, onto the next idea. tim You are welcome. As you can see...I sure don't know everything. The double woofer for the Heresy is still a good idea. I guess though a new cabinet would be in order. If you had a pair of Heresys, you could just use the drivers in a new cabinet w/o ruining the existing setup. Anyway, this topic WILL be brought up again...I assure you as I am coming up with some sort of custom center chanel. Happy moddin jc Quote Link to comment Share on other sites More sharing options...
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