Just got a pair of FF225WK's

Bob Brines · 09:57 PM

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

Bob Brines · 30th June 2011, 09:46 PM

Well, where did the attachments go? Trying again!

Bob

Scottmoose · 30th June 2011, 09:51 PM

Thanks (as always) for the measures etc. Bob. Interesting to hear your experiences with them so far.

BTW -127s? I guess that's supposed to be 207s?

Bob Brines · 10:00 PM

Thanks, Scott. Fixed

Bob

ra7 · 30th June 2011, 10:28 PM

Thanks for the measurements Bob. Always nice to see measurements.

Any chance of a CSD?

chazdrumzalot · 1st July 2011, 03:54 PM

Why such a big difference in top end between the MLTL and the raw driver?

Bob Brines · 1st July 2011, 09:49 PM

Quote:

Originally Posted by chazdrumzalot

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

IG81 · 4th July 2011, 12:30 PM

Thanks for the info there!

IG

norman bates · 5th July 2011, 12:17 AM

always nice to see real measurements.
Thanks.

Norman

Harderror · 2nd August 2011, 02:49 PM

Bob, any thoughts on the performance of these drivers yet? I am interested in trying them in my new design (Blizzard) and they sim pretty well. I kind of lost my taste for Fostex FF line but ChrisB stated that these may deal with some of the issues I have with the Fostex FF line. I would love to hear some impressions!

Tom

30th June 2011, 09:44 PM	#1
Bob Brines diyAudio Member Join Date: Jan 2003 Location: Hot Spring Village AR	Just got a pair of FF225WK's 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 by Bob Brines; 30th June 2011 at 09:57 PM.

30th June 2011, 09:56 PM	#4
Bob Brines diyAudio Member Join Date: Jan 2003 Location: Hot Spring Village AR	Thanks, Scott. Fixed Bob Last edited by Bob Brines; 30th June 2011 at 10:00 PM.

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30th June 2011, 09:51 PM	#3
Scottmoose diyAudio Member Join Date: Mar 2005 Location: UK	Thanks (as always) for the measures etc. Bob. Interesting to hear your experiences with them so far. BTW -127s? I guess that's supposed to be 207s?

30th June 2011, 10:28 PM	#5
ra7 diyAudio Member Join Date: Feb 2009 Blog Entries: 1	Thanks for the measurements Bob. Always nice to see measurements. Any chance of a CSD?

1st July 2011, 03:54 PM	#6
chazdrumzalot diyAudio Member Join Date: May 2009 Location: Seattle, WA	Why such a big difference in top end between the MLTL and the raw driver?

4th July 2011, 12:30 PM	#8
IG81 diyAudio Member Join Date: Feb 2008	Thanks for the info there! IG

5th July 2011, 12:17 AM	#9
norman bates diyAudio Member Join Date: Nov 2003 Location: iowa	always nice to see real measurements. Thanks. Norman

2nd August 2011, 02:49 PM	#10
Harderror diyAudio Member Join Date: Mar 2006 Location: Washington DC	Bob, any thoughts on the performance of these drivers yet? I am interested in trying them in my new design (Blizzard) and they sim pretty well. I kind of lost my taste for Fostex FF line but ChrisB stated that these may deal with some of the issues I have with the Fostex FF line. I would love to hear some impressions! Tom

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