I suspect you'd probably loose a little in transient performance with a shelving filter in place, but the basic tonality etc wouldn't change, as you say. For whatever reason, the damn thing clearly doesn't work sonically in this kind of load. You get some like that unfortunately, & there's very little that can be done in advance to predict it. 
serenechaos said:
Hello serenechaos,
I am somewhat confused. FE138ES-R should have some peak around 500Hz-4kHz and 10kHz. 10kHz peak may be ignored, but 500Hz-4kHz may by annoying.
You feel its sound is somewhat muffled. BVR should be innocent for muffled sound...
BVR should work, though response in the lower frequency range may not be enough.
Did you try removing the driver and hear sound directly? I think somewhat strange. Damping materials in the cabinet should not so much affect but moderately affect. You may try removing all the damping materials from the cabinet. Why don't you try this? You may insert the damping material back again, if you do not like absence of the material.
I am sorry for incomplete advice. It is very difficult.
Regards,
Shigeru
I don't remember where peaks were (don't have fr graph in front of me right now) but yes, it had one, as I remember, around 4.5K?, then it repeats @ the harmonic, 9k, & 18K or whatever it is.
so the LCR filter of .62 mH (12 AWG) Copper Foil Goertz, 15 uf oil can motor run cap, and 5.6 ohm/25w mills resistors were used as notch filter.
1st order crossover for 138 was another .62 mH (12 AWG) Copper Foil Goertz in parallel.
Ribbon tweeter used 6.8 & 4.7 Obbligato copper case aluminum film caps w/ .15 mH Copper Foil Goertz coil in between them.
Yes, this was wired so any or all parts of the circuit could be used together or left out for evaluation.
Circuit was determined by LEAP.
All this "extra circuit stuff" was an an attempt in desperation to cure the very annoying problem w/ the peak, and only after trying the simple 1st order cap on the tweeter for that part also.
The LEAP circuit works fine, I can live w/ that part of it fine.
Yes, I started w/ no damping in the cab @ all, left it that way for several days.
had some on the center brace, but took it out.
Yes, I've listened to the driver out of the box, in a sealed box, and in a TL.
I liked the TL best of the above.
I was planning on building a resonate pipe next.
As Scott said, "whatever reason" the thing doesn't seem to like this kind of load...
A friend has a feastrex 5" that sounds very much the same in the same type cabinet.
Strange.
so the LCR filter of .62 mH (12 AWG) Copper Foil Goertz, 15 uf oil can motor run cap, and 5.6 ohm/25w mills resistors were used as notch filter.
1st order crossover for 138 was another .62 mH (12 AWG) Copper Foil Goertz in parallel.
Ribbon tweeter used 6.8 & 4.7 Obbligato copper case aluminum film caps w/ .15 mH Copper Foil Goertz coil in between them.
Yes, this was wired so any or all parts of the circuit could be used together or left out for evaluation.
Circuit was determined by LEAP.
All this "extra circuit stuff" was an an attempt in desperation to cure the very annoying problem w/ the peak, and only after trying the simple 1st order cap on the tweeter for that part also.
The LEAP circuit works fine, I can live w/ that part of it fine.
Yes, I started w/ no damping in the cab @ all, left it that way for several days.
had some on the center brace, but took it out.
Yes, I've listened to the driver out of the box, in a sealed box, and in a TL.
I liked the TL best of the above.
I was planning on building a resonate pipe next.
As Scott said, "whatever reason" the thing doesn't seem to like this kind of load...
A friend has a feastrex 5" that sounds very much the same in the same type cabinet.
Strange.
Agreed about the Feastrex box, although the reasons are somewhat different. The 138 from a theoretical POV should be fine, but in your experience (which I don't doubt) isn't. Why, remains a mystery. My best guess is that the driver measurements were not done correctly, although I have to admit, the more I look at the published response graphs, the less convinced about the driver itself I become. I don't like all those peaks that are causing you such a headache for e.g.
On the other hand, I know exactly why the Feastrex cabinet doesn't work (way too much Vb), and repeatedly warned in advance that what was being demanded wouldn't sound right.
Result -it's being re-done, this time as I wanted to do it from the outset, using prior positive experience with the little Freddie cabinet. The new version should sound much better.
Hope the resonant pipe (Nessie variation?) works out.
On the other hand, I know exactly why the Feastrex cabinet doesn't work (way too much Vb), and repeatedly warned in advance that what was being demanded wouldn't sound right.
Result -it's being re-done, this time as I wanted to do it from the outset, using prior positive experience with the little Freddie cabinet. The new version should sound much better. Hope the resonant pipe (Nessie variation?) works out.
http://www.diyaudio.com/forums/showthread.php?postid=1472128#post1472128
Also see 2 posts up for some intitial checks.
Of course, there is another possibility at work here -I could have screwed up with the cabinet.
Also see 2 posts up for some intitial checks.
Of course, there is another possibility at work here -I could have screwed up with the cabinet.
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