Opinions on Eminence Alpha a 15"

[mayhem13]

Thinking of doing my first large format OB design and using parallel pairs of Alpha 15's from 250hz on down 2nd order active......opinions on this driver in and up to the intended range? I've heard pros and cons here and there but would like to know if spending more $$$ on woofers in this range is neccessary.......don't have disposable cash flow for this one.

Will also need some feedback on a fullranger or MT section for 250hz and up but that's a topic for another thread.

[Brisso57]

You've seen the twin-15A MJK design paper here:

http://www.quarter-wave.com/Back_Doo...ve_1_30_10.pdf ?

Doug

[Melon Head]

Troels and others who have heard it, prefer the deltalite II 2515 over the Alpha, however the Qts is vastly different so you have to keep that in mind when deciding the baffle size and what speakers to mate it with.

[djn]

I am running a single 15a in "H" frames per Martins paper. I have two of them. I don't see any need to do the double and my room is big.

[Godzilla]

>>> I am running a single 15a in "H" frames per Martins paper. I have two of them. I don't see any need to do the double and my room is big.

Same here djn... and my room is small.

Beta 12LTA in a 3cf box - port size

That said, i never heard any other 15" drivers. I do love the bass from these H-frames! If they creep to far into the 'main driver' the Alpha's do make themselves known. Keep them crossed low as possible and enjoy. Compared to the sealed powered sub i have on hand the H-frames win hands down.

Zilla

[ra7]

I'm running 15A in singles too. Although, I would not use it over 150 Hz. It doesn't quite have the midrange that a good full range can offer. Even at 150 Hz the sound thickens if you use a 6db/octave crossover.

That said, the deltalites are going to be with me soon, albeit for a different project. I'll give them a go in the OBs and see what I get.

[cuibono]

I third djn. I used one per side, and never felt lacking in bass. I would impress all my friends with them - they could play very loud.

I think when properly designed, they have no drawbacks besides being large.

[Godzilla]

>>> I think when properly designed, they have no drawbacks besides being large.

Yet they are the smallest footprint i am aware of for a 15" woofer other than a pure open baffle which doesn't sound as good, IMO.

I agree with ra7 about the 'thickening' sound as it creeps up higher in frequency. I use a plate amp to dial them in and think my setting is below 100hz. I'd be happy to try other drivers... i forgot, i have the 15" Jamo buyouts from PE playing on open baffle and they also sound fantastic! There's something about two 15" woofers pumping out bass in a home system that's just intoxicating... i can only imagine how 18" drivers would sound.

[Melon Head]

Originally Posted by Brisso57

You've seen the twin-15A MJK design paper here:

http://www.quarter-wave.com/Back_Doo...ve_1_30_10.pdf ?

Doug

Somehow I missed that.
Thanks for the link.

[djn]

Not to go off topic too much but this works for any sub. On my "H" frames I stacked two layers of scrap 1" marble on top. It makes a very noticable difference. This came about by accendent. I was moving some stuff around in my room and had the system playing. I picked up a box of LPs and set them on the "H" frame for just a minute while I adjusted my stance. I stopped, looked at the "H" frame and took the box off. Then put it on, then took it off. It really seems to tighten up the bass and becomes more clear. Kind of makes sense if you think about how little weight there is in the "H" frames, that woof is pushing the cab around and loosing clarity. P.S., I have my "H" frames on 1" spikes.

P.S.S., I get scrap marble at a marble cutters here locally. They can't sell scrap as no one has found a use for it so they have to pay to get it hauled away.