Just got a pair of FF225WK's

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
I opened the boxes this morning, did a quick T/S run and slapped them into the MLTL I designed for the FE207E's. Ran them for 5 hours and ran some RTA's.

The specs I got are not wildly out of line with the factory specs considering that this is with zero break-in.

The FR traces are:

Black: Gated 1/2m (4.8msec)
Brown: Combined driver/port
Gray: Ungated, unsmoothed 1/2m

The bottom end is as expected from the models and the ungated trace follows exactly the combined trace. The splice point will be 200Hz. Up to 9kHZ, my RTA matches the factory RTA very well. Above 9kHz, my RTA is ~10dB below the factory RTA. Maybe things will be different after a decent break-in, but I doubt it. I have never heard of the treble "coming in" after time.

My impression at this stage is that the FF225 is a smooth, well behaved driver that will support extended listening. At this point, detail is adequate but not outstanding. The top is nonexistent. This driver will require a tweeter. I have a pair of FT17H's laying around. I suspect that a single cap crossing ~6kHz will work will, since the FF225WK is dieing at that point anyway. I suppose that the stuff above 10kHz might need suppression, but maybe not.

BTW and OT, look closely those of you that want to see all of the wiggles in an RTA plot. 90% or more of the wiggles are nothing but room reflections. Once you get into the break-up region above say 3kHz, the raw trace gets smoother and smoother, and overlays nicely on the gated trace. The same result can be had with 1/6 octave smoothing. No information is lost, particularly since your ears are going to do a 1/6 to 1/3 octave smoothing anyway!

Bob
 
Last edited:
Well, where did the attachments go? Trying again!

Bob
 

Attachments

  • Specs ot of the box.jpg
    Specs ot of the box.jpg
    74.6 KB · Views: 1,093
  • New FR.jpg
    New FR.jpg
    82.9 KB · Views: 1,083
Why such a big difference in top end between the MLTL and the raw driver?

Darned if I know. The shape of my curve is about the same as the factory curve but 10dB down. This has nothing to do with my cabinet. The cabinet stopped affection the response curve way back at 300-500Hz. It's not my mic either. It was professionally calibrated to above 22kHz. What you see is what is actually coming off of this driver.

Bob
 
Tom,

I like them. They have a nice smooth sound, particularly with a bit of DSP. Good bottom end, better than the FE207E. Lacking on the top. Once I get off of a couple of other projects, I intend to mate the 225WK with the FT17H.

(I have had very poor luck using a tweeter with a full-range running wide open. I am convinced that this will only work with a proper XO on both drivers. If I get lucky, I think that I can roll off the 225WK 3rd order with a single inductor. If not I do it a proper 2nd order XO ~6kHz. That is a comfortable place to cross the FT17H anyway and it is probably not too high to get a decent off-axis power bandwidth given that the FT17H is horn loaded.)

I have lived with the 225WK's for a while now and they do a credible job with most classical, jazz and girl-and-a-guitar. They work on classic rock up through Pink Floyd and the like. Much heavier and you shouldn't be running full-rangers anyway. With an Xmax of 2.25mm, there is plenty of room for bass EQ, so they sound pretty stout, although I brickwall them at 30Hz.

Give them a try!

Bob
 
Bob Brines, anything to add or change to you impression of these drivers from ~2 months ago?

I also acquired a pair and got similar results for out of box parameters and response. Mine reside in Karlson "SK8".

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


They do quite well in there. HF is lacking though; I currently use some EQ at 20kHz and it helps nicely, but will look to implement a super-tweeter solution.

IG
 
Bob Brines, anything to add or change to you impression of these drivers from ~2 months ago?


IG

I never have thought that Fostex drivers take a lot of breaking-in. 100hr or so max. Maybe just me, but I think that longer break-in periods are more becoming comfortable with the sound.

Anyway, nice bass and mid-range. Definitely needs a tweeter, much more so than the FE207E. Because of the bump in the FR near 3kHz, an XO is a problem. I finally decided to let the 225 run wide open and cross an FT17H at 4kHz second order. Use a BSC filter and/or a zobel to contour things to your taste.

Bob
 
I heard about the FE series requireing a certain period of break-in, but never had these myself. I'll probably have to willingly drive the FF225WK hard in the Karlson to produce enough excursion to workout the suspension elements. :)

Regarding the ~3kHz bump, that's nothing next to the one on AD9710, inherent of it's straight-sided cone AFAIK. :D

IG
 
Tom,

I like them. They have a nice smooth sound, particularly with a bit of DSP. Good bottom end, better than the FE207E. Lacking on the top. Once I get off of a couple of other projects, I intend to mate the 225WK with the FT17H.

(I have had very poor luck using a tweeter with a full-range running wide open. I am convinced that this will only work with a proper XO on both drivers. If I get lucky, I think that I can roll off the 225WK 3rd order with a single inductor. If not I do it a proper 2nd order XO ~6kHz. That is a comfortable place to cross the FT17H anyway and it is probably not too high to get a decent off-axis power bandwidth given that the FT17H is horn loaded.)

I have lived with the 225WK's for a while now and they do a credible job with most classical, jazz and girl-and-a-guitar. They work on classic rock up through Pink Floyd and the like. Much heavier and you shouldn't be running full-rangers anyway. With an Xmax of 2.25mm, there is plenty of room for bass EQ, so they sound pretty stout, although I brickwall them at 30Hz.

Give them a try!

Bob

Hi Bob,

I am building Metronome Speakers using Fostex 225WK & FT17H. Would appreciate hearing your experience on Cross Overs that you were contemplating of trying.

Thanks!

Jay
 
Hi Bob (or anyone else with suggestions),

I just built my first ever pair of speakers. The Ceinwyn Chang horn for the FE168EZ. Though they are still unsanded/unpainted I have listened to them with and without stuffing and I'm only moderately happy with the sound. They seem a but thin in the treble and with too much stuffing in the box they sound empty in the bass too.

If I remove all the stuffing from the box it actually sounds fine in the low and mid range but the treble still bothers me.

I have heard that the Fostex drivers can actually lack top end. Do you have any suggestions?

I'm thinking of adding a simple small dome tweeter and crossing it over around 3-4kHz or maybe even higher.

Cheers!
 
Thanks for the suggestion Bob. My friend whose workshop I've been using to build these said similar and swears by the coax horn tweeters in his Altec 604s (shown behind my Ceinwyns in the photo I posted.)

I'll do some more research before I buy something. Now I have the boring bit left to do. Sanding and painting.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.