The FF85K Sprite

Jim Shearer · 11th June 2009, 12:36 AM

I’m busy right now building Metronomes for the Fostex F120A’s I bought last summer. However, I just bought a pair of Fostex FF85K drivers for a micro-Fonken build later this summer. Usually I put new drivers on OB (i.e. an old board) to check them out & get an idea of how they will sound, but I was afraid of hurting these little guys.

Others have put their drivers into cardboard boxes to check them out--not a bad idea! Just need to figure out how big a box I need. So I got out David Weems’ “Designing, Building, and Testing Your Own Speakers” and calculated a ported box for he FF85K. Works out to 1.77 liters and the port...Hey, that’s pretty much what I’d have if I cut the bottom off a 2 l soda bottle, glued a piece of wood to it, and added a bit of fiber fill!

So here it is: the FF85K Sprite!

(Note that Sprite is a brand of lemon-lime soda here in the USA.) Photo below shows The Sprite perched atop the Fonkens I built last summer.

How does it sound? Not bad. Especially considering that the drivers are fresh out of the box and the ‘cabinets’ are fresh out of the re-cycling bin. (But I do expect that the micro-Fonkens will be considerably better.)

Cheers, Jim

chrisb · 11th June 2009, 02:34 AM

Quote:

Originally posted by Jim Shearer

How does it sound? Not bad. Especially considering that the drivers are fresh out of the box and the ‘cabinets’ are fresh out of the re-cycling bin. (But I do expect that the micro-Fonkens will be considerably better.)

Cheers, Jim

Jim, I think you can count on that

planet10 · 11th June 2009, 03:42 AM

MJK · 8th July 2009, 12:59 AM

I heard the FF85K Sprite speakers this afternoon at Jim's house. Running with a sub to fill in the very bottom, these little drivers sounded great. I was extremely impressed. If they were not out of stock at Madisound there would probably be a pair on their way to me right now. I can visualize quite a few two way speaker designs that would be a bargain to build and perform way better then they should using these drivers.

planet10 · 8th July 2009, 01:16 AM

Quote:

Originally posted by MJK
I heard the FF85K Sprite speakers .... these little drivers sounded great. I was extremely impressed.

When i started working on FF85 i was worried about being able to sell them for what i'd have too... after i heard them i knew it was only a matter of getting sufficient people to hear them... and now with the Audience A3 double the cost of my version, they seem a real bargain.

Cal & i were talking about an array of 4 per side (like the Jordan, Bandor stacks that have lead to the A3) with woofers on the bottom -- this just after he heard uFonken. I was chatting with someone the other day, and he was speculating about whether the elevated HF of the A3 had something to do with countering the combing issues of multiples of these... FF85 seems to have a similar rise at the top (and you could buy an array of 4 stock ones for not much more a pair of A3).

I wonder if Madisound has had a bump in sales.

dave

MJK · 8th July 2009, 01:23 AM

The clarity without any spit or sizzle was really amazing. A very open and relaxing sound that we listened to for quite a while. It is definitely on my short list of drivers I want to try at some point. A two way OB/dipole system would be a very interesting combination.

planet10 · 8th July 2009, 01:23 AM

Quote:

Originally posted by MJK
I can visualize quite a few two way speaker designs that would be a bargain to build and perform way better then they should using these drivers.

Have you seen the Tysen thread?

A thread for Tysen and variations on FAST

dave

MJK · 8th July 2009, 01:28 AM

Quote:

Originally posted by planet10

Have you seen the Tysen thread?

I have now, that is another interesting idea. So many good ideas, so little time.

planet10 · 8th July 2009, 01:38 AM

Quote:

Originally posted by MJK
A two way OB/dipole system would be a very interesting combination.

We have that one in the queue... based on your Alpha 15 OB. And somewhere here a fellow in CA commented on the ones he built.

dave

kazoo · 8th July 2009, 01:31 PM

Just to chime in I made a pair of the uFonkens a while back. I needed some computer speakers at work. These are the perfect size to sit on the the desk. I have been listening to them for over a month now about 8 hours a day. These sound great. No fatique at all listening to them. The reason I have not posted pictures because they are still in plywood. I have not had a chance to veneer them. I will soon hopefully. But if anyone needs a computer speaker or is looking at a speaker in the 3" range these are the ones to get.

John

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Fe107e or FF85k?	type	Full Range	9	18th January 2009 05:58 PM
Mods for FF85k	badman	Full Range	26	28th May 2008 06:25 PM
Ff85k?	Kensai	Full Range	1	25th April 2007 11:22 AM
Looking for Foster FF85K	NickC	Swap Meet	0	16th April 2007 04:28 PM
amp for Fostex FF85k	tame	Multi-Way	0	28th February 2005 07:21 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

11th June 2009, 03:42 AM	#3
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 5

8th July 2009, 12:59 AM	#4
MJK Account disabled at member's request Join Date: Feb 2002 Location: Clifton Park, NY	I heard the FF85K Sprite speakers this afternoon at Jim's house. Running with a sub to fill in the very bottom, these little drivers sounded great. I was extremely impressed. If they were not out of stock at Madisound there would probably be a pair on their way to me right now. I can visualize quite a few two way speaker designs that would be a bargain to build and perform way better then they should using these drivers.

8th July 2009, 01:23 AM	#6
MJK Account disabled at member's request Join Date: Feb 2002 Location: Clifton Park, NY	The clarity without any spit or sizzle was really amazing. A very open and relaxing sound that we listened to for quite a while. It is definitely on my short list of drivers I want to try at some point. A two way OB/dipole system would be a very interesting combination.

8th July 2009, 01:31 PM	#10
kazoo diyAudio Member Join Date: Feb 2005 Location: Illinois	Just to chime in I made a pair of the uFonkens a while back. I needed some computer speakers at work. These are the perfect size to sit on the the desk. I have been listening to them for over a month now about 8 hours a day. These sound great. No fatique at all listening to them. The reason I have not posted pictures because they are still in plywood. I have not had a chance to veneer them. I will soon hopefully. But if anyone needs a computer speaker or is looking at a speaker in the 3" range these are the ones to get. John