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-   -   You say potato, I say potaato. You say FE126E, I say FE126EN (http://www.diyaudio.com/forums/full-range/177969-you-say-potato-i-say-potaato-you-say-fe126e-i-say-fe126en.html)

brucegseidner 26th November 2010 11:57 PM

You say potato, I say potaato. You say FE126E, I say FE126EN
 
In a related thread Chris shared that there was anecdotal evidence of the functional equivalence between the FE126E and F126EN. These units could be absolutely equivalent or this could be another case of "close, but no banana pulp."

I was set on building the Mikasa on my upcoming holiday. I had even decided how they were going to be finished, viewing the high art and good taste of the cabs on Vitalstates.com (thank you Ed - lovely, truly lovely woodworking).

I thought I had a line on some FE126E's in garage retirement but they have apparently become decrepit and the owner/seller mourns their demise.

So, now I am looking at the FE126EN if I can't pick up some retired FE126E's.(Don't be shy about PMing me.)

At a half inch smaller, the FE126EN is physically different than the FE126E. And, I am not the best judge of Q's and such for sonic equivalence as I compare the specs between the units. There could be a Vas difference, or a number of small distinctions without a difference.

As everyone knows, it is a lot of work to build and finish out something that has to sit in with furniture outside the audio mancave where unfinished ply and mdf is de rigueur. It would be a shame to not get it right. I have come to respect that Scott and Dave put enormous work into thinking through these designs and Chris must have a landfill of prototypes in an elephant graveyard of speaker carcases in his backyard.

I have a pair of old friends, some KEF B139's that are not presently being used..... But I will remove my tongue from my cheek.

How do the FE126E and FE126EN compare? Will a new pair of FE126EN's make the Mikasa sing as they should or will it be like putting a peri-pubertal lad in the Vienna Boy's Choir?

Bruce

FullRangeMan 27th November 2010 12:53 AM

I say F200A, very beautiful music with Alnico sound:santa2: not cheap thought.

Ty_Bower 27th November 2010 01:31 AM

Quote:

Originally Posted by brucegseidner (Post 2378161)
At a half inch smaller, the FE126EN is physically different than the FE126E.

Huh? I'll agree that Madisound advertises the new version as a 4" driver, and the old as 4.5". If you look at the datasheets for both, you'll see the baffle hole is exactly the same - 104mm. The piston area is exactly the same too - 0.0065m^2. Mechanically, they are the same size.

motosapien 27th November 2010 12:24 PM

Quote:

Originally Posted by brucegseidner (Post 2378161)
As everyone knows, it is a lot of work to build and finish out something that has to sit in with furniture outside the audio mancave where unfinished ply and mdf is de rigueur. It would be a shame to not get it right.
Bruce

For that reason I would steer towards a well documented folded horn who's driver is still in production. You don't want to wind up like Mel Brooke's character in Patriot when he's test sitting his wooden rocking chairs........

chrisb 28th November 2010 03:32 AM

Bruce, let's make this simple - the new production version of the Fostex driver with FE126 in the name is a direct physical drop-in replacement for the previous.

In the case of my own enclosures, I use CNC programs for rebated cutouts for three series of Fostex frame sizes, and several for Mark Audio.

The new 126s fit in the same cutout at the old ones.* No matter how frequently Fostex might other component parts in these drivers, my money's on the stamped frames remaining the same for however long they produce units of this nominal dimension in the FE or possibly FF series.

My comment regarding "anecdotal evidence of their suitability" was to address concerns that some folks had upon first viewing what appeared to be significant differences in published T/S parameters / FR curves between the two vintages. It turns out that several factors were involved, not the least of which is the well known fact that the previous specs were not entirely accurate.

I have personally heard both versions of this model and the new one works just fine. Mr S would phrase it even more emphatically.

* actually, now that I think about it, my last several builds using this model driver incorporated quick replacement mounting baffles for testing a range of drivers, so if you're intending to include a magnet brace (which I normally do), I can't speak to whether the internal mounting depth is exactly the same. I do know for a fact that during almost a decade, there was a small change in this parameter to the FE127E, so it never hurts to measure the unit at hand.


Dave's location allows at least one decent bonfire a year, so in a way that's recycling the carbon? :smirk:

chrisb 28th November 2010 03:47 AM

Quote:

Originally Posted by motosapien (Post 2378579)
For that reason I would steer towards a well documented folded horn who's driver is still in production. You don't want to wind up like Mel Brooke's character in Patriot when he's test sitting his wooden rocking chairs........


There are numerous well documented public domain designs as well as a couple available by subscription, all of which have been shown to perform better with any version of the FE126 than the Fostex hybrid novelty, but of course who can guarantee how long they'll be producing the driver?

planet10 28th November 2010 04:22 AM

The measured TSP of a small sample of FE126En (n=4), fell within the statistical spread of the old FE126 (n=200+). Madisound measured with the same results using completely different kit. If there are any significant differences, then the new driver has a slightly higher Fs (near the top of the FE126e range), and subsequent slightly higher efficiency. I have 20 more FE126En breaking in and will have more data soon.

The biggest question when the new specs arrived was the xMax. Rumour from Fostex, via a German distrib, is that the old spec was wrong. Given the numbers, if the new one is 1-way (accepted standard today) vrs peak-to-peak (often used) for the old, then the 2 are essentially the same.

On physical examination, the only way to tell the new from the old (ignoring the label) are the gold terminals and a slightly smaller (1mm?) diameter magnet.

You can use FE126En in Mikasa. If you really want the best suited driver i still have at least 2 pair of FE126eN left (old driver, tricked out) -- can be colour matched to your build.

dave


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