FE126E - F120A - FX120 Comparison , can you help

kmaier

Member
2007-07-12 1:42 am
Well, I have all 3 drivers here... and in the following enclosures:

FE126E - Ed's Hornshoppe horns

FX120/F120A - 10-liter ported enclosure on stands.

First, the FE126E is a different animal from the other two... higher sensitivity by a good margin but much less expensive with a stamped frame and ceramic magnet.

The FX120 and F120A shared some common components: die-cast frame, cone and alloy dustcover (different color on front, rear is the same). The main difference is the magnet assembly, the F120A being alnico and over twice the price of the FX120.

So, how do they sound (in my view)?

FE126E - well-known (all around) performer, very good bang for the buck and is flexible in varied designs. It's get loud with little input.... but I don't like the fact that it develops what I call "upper midrange shout" if driven too loud (starts shouting at 1-watt).

FX120 - an expensive driver (~$106) with a nicely done die-cast frame, cone assembly, etc. with a large ceramic magnet. Less sensitivity (so more power required for similar levels) but a much flatter response. Also note different enclosure... not recommended for a rear-loaded horn. In short, a more refined sound IMHO. Less fatiguing for long listening periods and better resolution.

F120A - a very expensive driver at ~$227 each. Main difference from above is the alnico magnet assembly, but the surround is also slightly different. Overall freq response similar but a bit flatter and rolls off a bit earlier on top. Sonically, this is significantly better! Alnico retrieves the low-level detail much better. You just need more power with these, 8+ watts but SET preferred. These are my first choice (small) Fostex drivers, but alas only 89dB.

Regards, KM
 

kmaier

Member
2007-07-12 1:42 am
The F120A has a foam surround which is very fine cell and a gray color. The FX120 also has a fine cell foam surround but is black in color. The question: Is it just a dye added or is it a different foam?

The cone appears to be the same Kenaf paper as the rear of both cones look the same. The FX120 has what appears to be a clear coating on the front of the cone. The F120A has a near-black color coating on the front of the cone. Again, the question: Is it just a dye added or a different coating?

One thing is certain... the F120A wins the listening test hands down.

Regards, KM
 
mp9 said:
kamier, how do the f120a & fx120 surrounds differ and are they both made of the same type of foam?

kmaier said:
The F120A has a foam surround which is very fine cell and a gray color. The FX120 also has a fine cell foam surround but is black in color. The question: Is it just a dye added or is it a different foam?


I have the FX120 and to me the surround looks and feels a lot more like rubber than it does foam.


kmaier said:
One thing is certain... the F120A wins the listening test hands down.

This fellow seems to like the FX120 over the F120A

http://www.diyaudio.com/forums/showthread.php?postid=1458998#post1458998

While it is hard to tell from the freq resp on the data sheet, the FX120 *looks* a little smoother and more extended.
 
marchel said:
Would it be possible to tweak the fx120 to make it even better? What are the weaknesses in its design that could be improved by DIYers?

I would say yes... for starters, lose the plastic boot and shape the rear of the driver. I will be EnABLing mine.

BTW, What do you think is the best box for the fx120?

Which box is best depends on your goals.

From the factory specs it should fit in the same, or close to the same, boxes as the FE127


dave
 

kmaier

Member
2007-07-12 1:42 am
Well, I've done extended listening to both the FX120 and F120A... there is zero doubt in my mind which is the better driver.... and yes, I've seen the freq plots as well... still the F120A has better high frequency response and is certainly more detailed and more natural sounding. I read the other post.... I simply don't believe what he has said is accurate.... then again, opinions are like...... so you should really decide for yourself.

Again, I've looked at the surrounds on both drivers.... within the past five minutes. When I first received the FX120 I thought it was rubber as well. But I've looked at much closer using a magnifier and it really does look to be foam, only darker in color

As for tweaks.... I'll leave that to Dave... however, I also removed the large rubber damping ring around the magnet.... I used some black hole pad and put a single layer around it instead.

Fostex provides a data sheet with a recommended enclosure (sometimes more than one) for all of their drivers. The F120A and FX120 are both shown in 10-liter ported enclosures but their actual dimensions and tuning vary slightly from what is shown on the website. Beyond these... follow Dave.

Regards, KM
 
Hi kmaier,

Thanks for the comments. I have not heard the F120A so I cannot comment.

I will take a closer look at the surround. The datasheet or fostex site does not comment on the surround material.

Good point about the rubber damping ring.

In addition to the 10 L BR enclosure, my FX120 drivers came with a Japanese datasheet which included a plan for the Fostex FX120 Recommended Double Bass Reflex Enclosure. It looks interesting, but I have not seen any built yet.
 

kmaier

Member
2007-07-12 1:42 am
Yes, I also noted the double-reflex enclosure.... but my datasheet (included with the FX120) shows the baffle mounting hole at 150mm diameter, which is incorrect for the FX120 or FX200 (both are condensed into a single datasheet). Still, probably worth the build.... pretty simple and can't take long to put one (or two) together.

Also compare the 10 liter enclosure dimensions on the included datasheet versus the 10 liter enclosure dimensions on Fostex' website (you have this clipped onto your webpage) and there are minor differences... including the port length by 5mm.

Still, the FX120 is a very nice driver for the $$... very nice indeed. Well made, good materials and should last a very long time. If you like the FX120 I would recommend you really think about getting a pair of the F120A drivers (while you still can... almost out of production).... they really move the ball forward. I do believe the improvements are mainly provided by the Alnico magnet (which is just very expensive to make these days) as the other differences between the two are minimal. Then again, the dark charcoal colored cone on the F120A just looks slicker ;-)

Regards, KM
 

ken mead

Member
2008-02-19 7:51 am
I found this information on the webb:


For many , alnico speakers are the final stop on the road to the promised land of tone. The sonic characteristics of alnico magnets -- sweeter treble, smoother midrange, and softer clipping -- are all attributes that ceramic-magnet speakers aren't designed to deliver. No wonder tone fiends call alnico "the musical magnet."

Alnico speakers (the word alnico is derived from the magnet's composition of aluminum, nickel, and cobalt) were standard issue in most amps up to the mid '60s. When the cost of cobalt increased due to its classification as a strategic metal during the Cold War, speaker manufacturers were forced to use other materials, ushering in the era of ceramic-magnet speakers. Ceramics cost less, and are more durable in high-power applications, but with many of today focusing on all things vintage, there has been an increased awareness of the sonic properties of alnico.