Fonken for F120A drivers?

jrebman

Member
2007-11-02 2:15 am
This year (2008 that is) I'll be looking to build an enclosure to put my F120A drivers in, and that will be used in my small office space (10.5' x 16' minus a 3' x 6' closet in one corner). Candidates considered so far have been the Metronome, Harvey, Mileva and a basic Fostex BR box. I'd like to explore the possibility of a Fonken but have no idea how to go about determining if this enclosure will be suited to the F120A.

Any advice/ideas welcome.

Thanks,

Jim
 
It is hard to convey how to design these, as i model as a BR looking for a specific shape curve for the roll-off and then lower the Q using a highly resistive port (ie push the box towards aperiodic). Sometimes i have gotten it on the 1st try (Fonken for FE127, µFonken) sometimes it takes a couple iterations (3 with the mFonken)

dave
 
gmilitano said:
Dave, so are you doing this by ear or are you looking at impedance?

Modeling to get me in the ballpark, experience to get me the 1st draft and then by ear for tuning. Finally impedance to make sure i'm in the intended ballpark.

I had a quick look at the F120A realier to day, and it looks like it will fit into the miniOnken/Fonken envelope so i'll just need to detail the ports slots.

dave
 

jrebman

Member
2007-11-02 2:15 am
Bud,

As of right now my plan would be to do a scratch build, but if the flat packs become available before then (read, warmer weather) then I'd definitely consider that as well.

I'm sure Dave and Chris would build a great cabinet, but not sure I can afford that -- at least not for a while.

Any listening reports yet?

-- Jim
 
Hi Jim,

I have finally listened to the F120A drivers enough to understand how they work.

The sound character is quite open above 1 kHz or so. Reasonably complete transients above 4 kHz and a top end that begins to roll off at about 12 kHz.

There are no indications of poorly utilized metal in the central aluminum dome. And that is quite unusual. I suspect that there may be some damping material or a soft glue in the joint to cone, as there is a pretty strong, narrow, dip in information content below the realm of the aluminum.

There is reasonable information, though they are really just hinting at the fundamental textures, in the right hand of piano's, the bell of drum heads, chest of female singers etc.

This becomes very noticeable in complex Red Book orchestral pieces.

In all, very good candidate's for EnABL. My real challenge will be to get the paper cone to shed more high frequency energy than it does now. With that accomplished they will be a very wide dispersion speaker, probably more so than the Fe 127 eN. Not certain where they will fall in the sweetness realm, but the aluminum dome is very well done. I have good reason tp hope that they will throw a very large sound field with excellent depth and internal clarity.

Bud
 

kmaier

Member
2007-07-12 1:42 am
planet10 said:
It is hard to convey how to design these, as i model as a BR looking for a specific shape curve for the roll-off and then lower the Q using a highly resistive port (ie push the box towards aperiodic). Sometimes i have gotten it on the 1st try (Fonken for FE127, µFonken) sometimes it takes a couple iterations (3 with the mFonken)

dave


Dave,

Are you making enclosure plans available for the uFonken? I have a new pair of FF85K drivers... sounds like an ideal setup for really small.

Regards, KM