Jim Shearer's Fostex FF85K and Eminence Alpha 15A Open Baffle Speaker

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Legis

Legis

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Joined 2009
ChestofFur said:
I've had my speakers up and running for about a week on some test baffles and I'm pretty satisfied. The Founteks didn't quite work but the ff85k do the trick. Both the little drivers are great, btw. Sorry, no measurements.

The speakers play loud enough for me and my living room is decent sized. The drivers blend together nicely and the sound doesn't hurt my ears at all (always a good sign). Some might prefer a speaker with a tweeter but I think they do the job. I'm still playing around with placement. Sometimes the lowest bass notes sound mushy but it could just be recordings or the room or my amp or maybe i just don't know what bass should sound like.

I definitely think these require a little power. My Super-T couldn't control the woofer.

This was a really fun and not too difficult project.
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Hi, why didn't the Founteks work so well? Becauseof the lower sensitivity or worse sq?
 
ChestofFur

ChestofFur

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Joined 2009
Sorry for the late reply. I'm not really sure why they didn't work as well as the fostex driver but the specs of the fountek were different then those specified in the design so I was expecting it. Although I should say I didn't do extensive testing in different rooms and obviously I don't have any measurements.
 
Jim Shearer

Jim Shearer

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Joined 2007
On a recent visit with MJK, I listened to the Founteks in an OB system with the 18" Goldwood H-frames. They were bi-amped, and thus compensated for sensitivity issues. Compared with Fostex FE126e run in the same configuration that day, the Founteks gave what I would describe as a flat presentation--no sound stage depth. One the one hand they didn't do much wrong, but then they didn't do enough right.

Cheers, Jim
 
C

chrisb

Member
Joined 2002
Jim Shearer said:
On a recent visit with MJK, I listened to the Founteks in an OB system with the 18" Goldwood H-frames. They were bi-amped, and thus compensated for sensitivity issues. Compared with Fostex FE126e run in the same configuration that day, the Founteks gave what I would describe as a flat presentation--no sound stage depth. One the one hand they didn't do much wrong, but then they didn't do enough right.

Cheers, Jim
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I'm not familiar with the Fountek, but for sure "flat" or lacking in stage depth would not describe the FE126E in any application I've yet heard.
 
Jim Shearer

Jim Shearer

Member
Joined 2007
To be sure, I very much liked the FE126e--nice detail and sound stage. That said, I still think I prefer the FF85k for most material. The FE126e will probably play louder and may be better on large scale orchestral works where the FF85k begins to struggle. E.g., I'm not fond of playing Mahler's 8th, the Symphony of a Thousand, on the OBs w/ the FF85k. But over-all, I'm still lovin' the OBs w/ the 85. As they say: You pays your money and you takes your choice.

Cheers, Jim
 
T

then_dude

Member
Joined 2003
hello Jim

i got my ff85k,

but need to buy some other stuff. like the woofers, X, and amp(s)

i wonder:

1)can i make use of the eminence deltalite ? a single 12 or 15 inch version.
2)how does the X looks for active biamping ? i wonder if i buy two tripath (STA517b) i could run them active. (i guess i need a 4 way volume pot)

thanks a lot
 
Jim Shearer

Jim Shearer

Member
Joined 2007
then_dude said:
1)can i make use of the eminence deltalite ? a single 12 or 15 inch version.
2)how does the X looks for active biamping ? i wonder if i buy two tripath (STA517b) i could run them active. (i guess i need a 4 way volume pot)

thanks a lot
Click to expand...

If you look at Martin's papers on his site ( Quarter Wavelength Loudspeaker Design ), you can see that if you use a woofer with a lower Q(ts) you will need to do some EQing.

An active XO and bi-amping will work just fine.

Cheers, Jim
 
Jim Shearer

Jim Shearer

Member
Joined 2007
Without modeling this, I would expect the Q(ts) = 0.59 is too low to work well on OB without going to bi-amp and using EQ. And remember that the baffle width is part of what makes Martin's small, passive OB work, so decreasing the width would also likely make EQ necessary. Plus, the cost of the 10" isn't all that much less than the 15"--and the performance will be much less than the 15".

Bottom line: I don't think I would bother.

Next thought: How about giving up on the OB woofer & making a simple OB with a driver like Wild Burro's Betsy?

Cheers, Jim
 
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superlian

Member
Joined 2010
Summer project for the boys (14 & 15 years) with fe83en and a15a.
We use a NAD amplifier and Project USB dac connected to Spotify premium (320 kps).
Dubstep is not my cup of tea but they are very satisfied
It is playing loud and with punch. The boys said wow. The bes.t system at school :)

An externally hosted image should be here but it was not working when we last tested it.

Uploaded with ImageShack.us

http://www.youtube.com/watch?v=ncT8CRszM8E
 
Godzilla

Godzilla

Member
Joined 2005
speakerprojects.wordpress.com
Wow is right! Great looking system... i had a little pair of bookshelf AR 15s when i was in school... dull, boring, flat sound... but they were considered pretty darn good back then. I don't even think powered subs were available back then to enhance the bass? Love that you're using the NAD... amazing how we can get such great sound on the cheap these days. I bet it sounds fantastic! Great job dad!
 
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