Fostex FF225K

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#21
Since it hasn't been mentioned, the official cabinet for the FF225K was the BK20, which is or was available from Madisound as a flat pack kit. RCA-Fan (Bill Woods) also tested his backhorn with the FF225K, in reality not just sims. IIRC he liked it, saying it was a bit on the mellow side. The plans are out there somewhere.

If you were happy with the back horn sound, it might be logical to consider these two options first?

I'd suggest going a little higher tuned with if building a Karlsonator for this, scaling .9 for height would be closer to the K'ator 8 plans. maybe increase port area. I don't like trying to squeeze too much low bass out of drivers if it's harmful to midbass oomph. Equally, I'd be a little concerned with weak mid/upper bass in a BIB with this driver. Probably room dependent. You say you've tried this combo?

The Xmax on these is unrelated to Xmech. They are nearly even wound I believe, like old Altecs.
 
#22
Right, they had some very distant similarities on that score (& may have been aesthetically 'influenced' by the LE8T).

IIRC, although they often found their way into the BK20, it wasn't the 'official' box for them -they only put out BR boxes on their site at any rate, although it may have been in the long out of print craft manuals (?).
 
#23
I have made a BiB cabinet before, but that was with the Veravox 5S drivers and in a smaller room.

My room is an 'L' shaped room and about 200 sq. ft (18 sq. m) and 7.5 ft (2.3m) high:


IMGP1303 by RSdesignUK, on Flickr


IMGP1306 by RSdesignUK, on Flickr

Do you think the FF225K in BiBs may be a bit too big for that room?

I will do some more research into the Karlson boxes and the BK20.
 
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#27
Scottmoose said:
IIRC, although they often found their way into the BK20, it wasn't the 'official' box for them -they only put out BR boxes on their site at any rate, although it may have been in the long out of print craft manuals (?).
Click to expand...

Could be. I saw it in the little info sheet that came with some FF125K I bought. IIRC there were plans for all the BK horns in it, as well as BR alternative enclosures. I'll see if I can dig it up, but it may have been tossed. This was some years ago, when they were still made in Japan.
 
#36
Glad to see these went to a good home 😉. If you're enjoying the OB sound maybe it'll be worth experimenting with aperiodic enclosures where you can hopefully keep the open sound quality but with increased bass response. Some irregular enclosure shaping might give the very best results, I was surprised at the difference that a single sloping enclosure wall could make with full-range drivers.
 
#40
inrank, I simmed your project using Thorsten's old (and excellent) open baffle spreadsheet. I think you will be pleased with the sim. Add bass help and you will have something really special (and maybe a piezo or some other kind of helper tweeter - probably just need a 1uf or 1.5uf cap and you're done). Easy and great, enjoy!

Zilla
 

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