Hey guys!

I just saw where Fi is having a sale on their "X" Series subs. (Two 10's for $150 shipped, two 12's for $160 shipped.)

I have not used or even heard Fi subs before, but I have read some good stuff about them.

Specifications are as follows:

10" DUAL 4
Fs: 25.9 Hz
3.9 Ohms/coil
Qms: 3.90
Qes: .35
Qts: .32
Mms: 110g
Cms: 0.34mm/N
Sd: 310cm^2
Vas: 45.7 l
Spl: 85.4dB 1W/1m
Bl: 20 N/A
Xmax: 16mm
Rms: 300W
Sealed box: .5-.8cuft
Ported box: .9-1.5cuft
Sub OD: 11.0
Cut ID: 9.25
Mounting depth: 5.25
Displacement: .07cuft

12" DUAL 4
Fs: 25.7 Hz
Re: 3.9 Ohms/coil
Qms: 4.01
Qes: .38
Qts: .35
Mms: 120g
Cms: 3.2mm/N
Sd: 480cm^2
Vas: 104.1 l
Spl: 88.6dB 1W/1m
Bl: 20.0 N/A
Xmax: 16mm
Rms: 300W
Sealed box: .9-1.3 cuft
Ported box: 1.6-2.2 cuft
Sub OD: 12.500
Cut ID: 11.125
Mounting depth: 5.750
Displacement: 0.10cuft

I'm thinking about getting a pair of 10's or a single 12 for my C5 Vette?!?! Anyone here have any experience with them? Opinions?

Mark

 

Looks like 1.2 cubic feet would be perfect for the 12. So no stealthbox for you. Even hangover/flush box would be slightly small.

The 12 is -3db @ 50hz, which honestly, is not very good for a 12. so low end output doesn't seem so promising.

The 10 models up like an 8" sub. -3db @ 57hz. This is in a .4 enclosure with qtc of .71.


Now the 10 models up not bad in a ported box, .75 with -3db @ 37hz. Tuning @ 30hz. (so you'd want a subsonic filter somewhat below that.)
Port length would need to be huge, though.

If Spkrboy shows up, I'm sure he'll make more sense of the specs though.

 

ive heard some nice things about these guys and their stuff

 

I know exactly nothing about this company. From the appearance of their drivers, it seems they don't actually build anything, but provide specs to another manufacturer for building. The drivers Mark quotes don't seem to be on the site anywhere (unless I missed something). One thing you have to worry about with situations like this is when you factor in power compression. Cheap drivers use inexpensive magnet materials that tend to lose force with increasing temperature. That may not be a worry here, but it's still a question mark.

That said, I like the SPL quote in 1W/1M, so they get some credit there.

The 12... the SPL spec of 88 is likely a VC-series number. The EBP is 67 indicating it's better-suited for a sealed box, but that's not an absolute. The ideal vented box is 2.7 ft^3 tuned to 28 Hz, having an F3 of 29 Hz. Not really reasonable in a smallish passenger car. A sealed box of 1.2 ft^3 gets you a Qcb=52 with an F3=52. A box 0.5 ft^3 gets you to Qcb=1.0 and F3=58. They may look similar, but the group delay will make the smaller one boomy and slow.

Kale's right, the sealed 1.2 is ideal and too big for a stealthbox. However, IIRC, the stealthbox is about 0.75 ft^3. That gets you a Qcb=0.85 or so. That's easily in the range where strategic polyfill treatment can drag it back down to 0.707, but at a small SPL cost. The polyfill is strongly recommended for other reasons anyway.

Remember that woofer impedance tester you asked about a couple months ago, Mark? That thing is ideally-suited to getting the polyfill exactly right. Using something like that, you can easily get that 12 to perform well in a stealthbox, no question.

The 10:
EBP=74 (equally suited to vented or sealed)
vented: VB=0.92, Fb=30, F3=33
sealed, Qcb=0.707: Vb=0.4, Fb=58, F3=58
sealed, Qcb=1.0: Vb=0.2, Fb=78, F3=61

 

Thanks for chiming in, Spkrboy! (Sorry to hear about the ankle... but if it means that you will spend more time here...)



Kidding...

The drivers I was referring to can be found here:

http://www.audiojunkies.com/blog/712

They look like this:



You were right that they were not on the main web page... I had to hunt them down after being told about them on another forum.

The 10" modeled well in WinISD at 0.88 ft^3 tuned to about 32-33 hz... which is close to what you listed at VB=0.92, Fb=30, F3=33hz.

Maybe it would be worth it to buy a pair for 'testing' purposes?

While I'm bending your ear... what subs do you like? Why? What type of music do you listen to?

Get well soon, dude!

Mark

 

you may get some more (although biased?) information about that brand over at the infinate baffle forums. from what i recall when i was doing my home IB setup (which came out awesome btw ) the fi subs were widely used for those setups.

http://ibsubwoofers.proboards51.com/index.cgi

 

Thanks for the good wishes. Appreciated.

Possibly. After looking around the site a bit more, the Q drivers have my attention, too.

Mostly classic rock, rock-based jazz and orchestral classical.

The three greatest-performing subwoofers I've ever had the pleasure to use... highly-efficient, low-distortion, low power-compression, extraordinary build-quality:

3: Audio Concepts Comp 12 (still use 2)
2: JBL 2206/G
1. JBL 2226/G (still use 2)

Scott.... what sub did you finally settle on for that IB?