I just destroyed a pair of FE166En's

[Bob Brines]

Following conventional wisdom, I Mod-Podge'd and phase plugged a pair of Fostex FE166En's. Here are the FR plots:

The white trace is the unmodified FE166En.
The red trace is after doping with Mod Podge.
The blue trace is with P10 phase plugs installed.

The first chart is on axis.
The second chart is 15* off axis.
The third chard is 30* off axis.

The doping sucked the life out of these drivers. They now sound dull and uninteresting.They sound a lot like BOFU's, but without the guts. Yes, any hint of sibilance is gone, but at what price. These modified drivers absolutely required a tweeter.

I doped the whizzer as well as the main cone. My reward is a huge spike just over 10kHz. I am hoping that I can remove most of this by kneading the whizzer to soften it up.

There is a lesson in here somewhere.

For your amusement, the last three charts are off axis comparisons, Stock, Mod Podge, and Mod Podge'd and phase plugged. The traces are

White 0*
Red 15*
Blue 30*
Green 45*
Yellow 60*

Bob

[bigaudioscotto]

Hi Bob
I think I have done my last Enable and mod podge treatment.
I just did a pair of 126en and don't like the results,
just way to bright sounding you hear all the details
but just to much, I guess I lean toward a warmer sound,
enable is just way to in your face sounding to me.

[mor2bz]

I don't get it. Looks like they actually go higher, and the peak @ 10k is nicely
diminished off axis. I know, charts don't tell it all, and if you don't like it, then
you don't like it.

you could also throw some more stuff on them (dammar) as you have nothing to lose.

[mor2bz]

cut out the whizzer, sand the driver, add a tweeter?

[Jim Griffin]

In my opinion nothing good can be gained by most cone treatments on good drivers. The various treatment processes are just too unpredictable to merit do it in my opinion. If cone treatment were needed, then the original manufacturer would have done it. Cone treatments should be reserved for cheap, throwaway drivers. If you wish to have a better driver, buy one and enjoy it as the manufacturer intended.

[planet10]

Bob,

Need to know more details about your application. It is well known that too heavy a hand can screw up the HF.

dave

[planet10]

Originally Posted by bigaudioscotto

I think I have done my last Enable and mod podge treatment.

Scott,

Please post a picture of your application, it will give people some important context to your results.

dave

[ultrakaz]

What were your expectations? And what didn't you like about the sound of the Fostex?

Don't feel too bad. You may have well destroyed the Fostex, but is worth it. Not only to satisfy your curiousity, but gained knowledge of what this particular mod does. There is no substitute for personally acquired empirical knowledge, especially in matters of taste. "Conventional wisdom" or assumed knowledge is worthless in this regard.

After destroying a pair of Lowther DX55, I've come to the conclusion to just let the driver be itself. There was a temptation in thinking that a different mod or more or less of the same mod would be better, but that is the path to economic ruin and frustration......And even if I had unlimited resources and hundreds of pairs of the same driver, why not just look for a better/different driver that suited my sense of good sound(?).

The only exception is a pair of "enabled" Fostex F200a which unmodded is stinky-compressed/undynamic in mids and treble. However, that mod was done by Bud, himself after he had enabled a previous pair or two, and hundreds of other drivers for years prior.

The Fostex guys have been making drivers for quite a while, so they know what they are doing. Like it or not it is what it is. I would not try to "improve" any well engineered product, unless 100% reversible and proven exactly on this particular product.

[jimbro]

Well my plan is to order some enabled drivers from someone who knows what they're doing (Dave) and some stock drivers and decide for myself. Enabling is a labor intensive process and would add significantly to the cost of any driver and might be a hard sell in a competitive market. Don't know if you consider chr70s "cheap throwaway drivers" but in my opinion it's the end result, not the cost, that determines the worth. Of course cost does play a significant role for a lot of us.

[Bob Brines]

Originally Posted by mor2bz

I don't get it. Looks like they actually go higher, and the peak @ 10k is nicely
diminished off axis..

The on axis trace with the phase plug brickwalls at 5k and doesn't recover to the unmodded traces until 9k. THAT's the problem. The spike at 12k isn't extension, it is a resonance that needs notching out.

Bob