I think looking at eminence's recommended cabinets would be at least a place to start.
http://www.parts-express.com/pdf/290-410c.pdf
However, none of them look particularly impressive. I would be tempted to just run sealed, with a separate sub-enclosure for your alpha 8.
My 2c -- a 2way with the beta 12a-II beats your 3way, and is cheaper/easier....
http://www.parts-express.com/pdf/290-410c.pdf
However, none of them look particularly impressive. I would be tempted to just run sealed, with a separate sub-enclosure for your alpha 8.
My 2c -- a 2way with the beta 12a-II beats your 3way, and is cheaper/easier....
For a conventional 15" 3-way, the Delta Pro 15 would be the lowest end of the food chain worth looking at. I'd recommend one of the Kappa series (the basic steel frame model is fine). If cost is the issue use a 12" - a better 12 will go just as low/loud. Delta 12LF beats Beta 15 in everything except OB designs (the 15 is intended for lowish-power open back instrument cabs).
Thanks for feedback !!!
jbell : i know eminence recomended cabinets but at large vented cab
they say Vb=6 cu.ft for 100W ,
i dont know if its a realistic simulation with eminence designer.
wg_ski : yes Delta 12LF is better
but now i have those 2 beta 15 a and i must finish with them
c2cthomas : Ok. i will post pictures too
Yunick : cool
the crossovers are :
bass 280hz 12db/oct
med 700hz 6db/oct and 2,8Khz 6db/oct
tw 7,2Khz 18db/oct
what do you think?
after i will know the best Vb i will start to build them
jbell : i know eminence recomended cabinets but at large vented cab
they say Vb=6 cu.ft for 100W ,
i dont know if its a realistic simulation with eminence designer.
wg_ski : yes Delta 12LF is better
but now i have those 2 beta 15 a and i must finish with themc2cthomas : Ok. i will post pictures too
Yunick : cool
the crossovers are :
bass 280hz 12db/oct
med 700hz 6db/oct and 2,8Khz 6db/oct
tw 7,2Khz 18db/oct
what do you think?
after i will know the best Vb i will start to build them
OK....
Going to give you an alternative view....
Looking at the basic specs... you can use some OB tricks in a sealed box format... all depends on how much efficiency you can... or are willing to trade away...
You can put a large inductor in series with the woofer.... just for giggles.... a 18Mh iron core... (say a 16 ga. with a .75 ohm RE) and for the moment ... lets assume we must work with a 5 cu. ft. box... which with stuffing can look like a roughly 6 cu. ft. box to the woofer... assuming we can gain a 20% effective volume increase...give or take from the stuffing.
Now by adding the inductor we do three very important things... we increase the driver QTS... to ... say .65... and we lose about .5 DB driver efficiency because of the added resistance.... BTW..this driver's true efficiency in the bass region is about 96. DBW something... and by adding the inductor we impose a first order roll off begining around 70 Hz, or so (-3db). Also... all of the 15" Beta's I have measured had an FS around 31 Hz after break in.
What we are trying... need to do is drive down the box QTC ... to about .6 -.7 range or so. This will tilt the response downward in the upper bass and midrange. And it will rid us of the large response peak we would normally see at about 70 Hz when we put this woofer in a box of 6 cu. ft volume. There is no free lunch... so we will be trading away overall efficiency... about 4-5 db to get a flat response... but we will be flat into the upper 30's in a sealed alignment... with a realitively low 12 db/octave roll off from there on down... this means at 32Hz the system will only be down 4-6 DB... and with some room gain we will see an in room response down only 1-3 DB. It all comes down to what you are willing... or able to trade away... and relative to an OB design (my favorite BTW)... you will be more efficient.
Just a way to make lemon aid out of lemons... and using what you have to get to a potentially great HI - Fi solution. And I have done this before with similar drivers.
Going to give you an alternative view....
Looking at the basic specs... you can use some OB tricks in a sealed box format... all depends on how much efficiency you can... or are willing to trade away...
You can put a large inductor in series with the woofer.... just for giggles.... a 18Mh iron core... (say a 16 ga. with a .75 ohm RE) and for the moment ... lets assume we must work with a 5 cu. ft. box... which with stuffing can look like a roughly 6 cu. ft. box to the woofer... assuming we can gain a 20% effective volume increase...give or take from the stuffing.
Now by adding the inductor we do three very important things... we increase the driver QTS... to ... say .65... and we lose about .5 DB driver efficiency because of the added resistance.... BTW..this driver's true efficiency in the bass region is about 96. DBW something... and by adding the inductor we impose a first order roll off begining around 70 Hz, or so (-3db). Also... all of the 15" Beta's I have measured had an FS around 31 Hz after break in.
What we are trying... need to do is drive down the box QTC ... to about .6 -.7 range or so. This will tilt the response downward in the upper bass and midrange. And it will rid us of the large response peak we would normally see at about 70 Hz when we put this woofer in a box of 6 cu. ft volume. There is no free lunch... so we will be trading away overall efficiency... about 4-5 db to get a flat response... but we will be flat into the upper 30's in a sealed alignment... with a realitively low 12 db/octave roll off from there on down... this means at 32Hz the system will only be down 4-6 DB... and with some room gain we will see an in room response down only 1-3 DB. It all comes down to what you are willing... or able to trade away... and relative to an OB design (my favorite BTW)... you will be more efficient.
Just a way to make lemon aid out of lemons... and using what you have to get to a potentially great HI - Fi solution. And I have done this before with similar drivers.
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