Zen Mod said:
Papa,
I've found a place that has Alpha 12's and 10's (and there's a bass rig with 4x10's out there on the 'bay at the moment), so that's what I'm trying to sim with MJK's sheets at the moment (a curse on having to work at the same time!). The FR is a version of the FE103, a Coral with the 'holey' basket. So, by using the same drivers as in Martins' OB article I wouldn't have to do that much actual work on the design (spoken like a truly lazy person - well, it is supposed to get to 42C - or 108F - today).
I use several (five per channel in parallel) ten inch 16 0hm drivers with a QTS around .84 each. In parallel they are quite sensitive. Cost was around 150 US for all of them on closeout. They aren't available any more as far as I know. "Madison Warrior 10"
The alpha 15 is slow, sluggish, resonant and overall terrible (distorted) compared to reality (like a bass, cello, piano, ect) - this was with a pair mounted on a five foot by five foot sheet of baltic ply driven by several different good amplifiers.
The alpha 15 is slow, sluggish, resonant and overall terrible (distorted) compared to reality (like a bass, cello, piano, ect) - this was with a pair mounted on a five foot by five foot sheet of baltic ply driven by several different good amplifiers.
Magnetar said:
Re the Alpha, maybe so, but it's a relatively cheap place to start, and I can create Martin Kings' OB's with the same drivers - then I've got a place to start from. I tried simming the drivers in a 5' x 5' (instead of the 24" x 40") and found a big bloat below 200Hz (more than 6dB) and a big suckout at 300Hz (again more than 6dB) using the same crossover and driver positions. Maybe that accounts for some of the problems you encountered?
I've also got a cheap multi-driver possibility with some local drivers (possibly as few as 2 per channel). And a pair taken from an old pair of Pioneer speakers which are very pretty (and efficient). But with the temperatures over 100F (40C) at present, and having been too busy the last couple of months to do anything, it'll be a while before I get to them.
Cloth Ears said:
I multi-amp and use more efficient mid treble. My comment is about the general sound quality but yes I can see how a smaller baffle will sound different. I use the same board (different bolt in inner baffles) to test drivers to try and keep a reference. The alpha 15 were remarkably poor.
Good luck, stay cool - it's snowing here..........
Greetings, Cloth Ears I can certainly relate to the temp,,, Ive just moved from Melb to Inverloch and even with the tempering of the ocean New Years Eve day was foul. Have you read the thread on Audiocircle relating to the use of one Visaton B200 and one Alpha 15 per side open baffle. They are simply using a fat inductor on the Alpha to cut off above i think 200 hz and running the b200 full range and the users who mostly have been experimenting with the b200 fo years report excellant results. With all due respect to Magnater I guess people have different ideas as to what constitutes good bass as well as the application. I for one am hoping to try the Alphas with my B200 as in the setup as proposed in the AC thread will hopefully allow me to **** off my crap plate amp and run both off my 300b set. By the way Cloth ears your user name always reminds me of Thomkinsons' School Days (Ripping Yarns) which always brings a smile to my face
peace and goodwill fergs
peace and goodwill fergs
fergs, I've gotta know what "**** plate amp" was (I know the other one).
For my first OB attempt, I'm not really going for best sound quality, rather I'm looking to create something that works with a simple passive crossover, is reasonably smooth in frequency response and isn't too horrible for the missus to have in the house (and 24" x 39" might just make it).
Once I've gone there, then I might have a look at further mods. I've got a few active crossovers and amplifiers lying around (and I'm not afraid to use them) so I can handle mismatched efficiencies. But there's such a lack of high Q woofers around (for a reasonable price) that I'm grabbing them where I can.
I've also found the Jaycar 12" paper cones have a high Qts (Qes is 2.32!). Using a few of them (2,3 or 4) might be a worthwhile investigation also - but only after I've convinced SWCTPS (She Who Controls The Purse Strings).
For my first OB attempt, I'm not really going for best sound quality, rather I'm looking to create something that works with a simple passive crossover, is reasonably smooth in frequency response and isn't too horrible for the missus to have in the house (and 24" x 39" might just make it
).Once I've gone there, then I might have a look at further mods. I've got a few active crossovers and amplifiers lying around (and I'm not afraid to use them) so I can handle mismatched efficiencies. But there's such a lack of high Q woofers around (for a reasonable price) that I'm grabbing them where I can.
I've also found the Jaycar 12" paper cones have a high Qts (Qes is 2.32!). Using a few of them (2,3 or 4) might be a worthwhile investigation also - but only after I've convinced SWCTPS (She Who Controls The Purse Strings
).
Wow, that gets censored...
At the moment I've already got a pair of holy-basket Coral FE103's as well as a pair of Magnavoxes of some description and a pair of Pioneer FB13 woofers. And lots of wood and wire and caps and inductors. So all I was looking for was the Alpha's to start the experiment from a known item (MJK's OB design). Then I can measure, simulate and build other designs based on my likes and dislikes of the first attempt.
My budget for the Alphas is probably going to be about $130...
At the moment I've already got a pair of holy-basket Coral FE103's as well as a pair of Magnavoxes of some description and a pair of Pioneer FB13 woofers. And lots of wood and wire and caps and inductors. So all I was looking for was the Alpha's to start the experiment from a known item (MJK's OB design). Then I can measure, simulate and build other designs based on my likes and dislikes of the first attempt.
My budget for the Alphas is probably going to be about $130...
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