FE108EZ as a Midrange

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Greetings,

How well would the FE108EZ work as a midrange driver in a three-way triamped system? Crossover at about 350 and 2800 My calculations show that it would require only a 1.05L enclosure.

Is there a driver out there with a better midrange around $80?

-The Audioferret
 
It'll work. However, if you're going for a 3 way, and limiting the driver's response like that (that's not a criticism by the way), I'd forget using full-range units entirely, and just go straight to the famous Vifa PW13 5 1/2". That's what it's designed for. Efficiency is high and it's still probably the flattest measuring and best sounding midrange (I suppose it can just about scrape being called a mid-bass, but it doesn't have a lot down low) in the world. You'd only really reap benefits using the FE108ESigma if you took the driver much, much higher. That in itself might not be a bad plan as you could then cross to a tweeter (if you even bothered -the Sigma doesn't really need it) well above the human ear's most sensitive hearing range.
Have a look at Lynn Olson's comments on driver selection for his Ariel 2 way TL: http://www.nutshellhifi.com/Arieltxt1.html#td
His comments on crossover optimisation also make interesting reading: http://www.nutshellhifi.com/Arieltxt2.html#top

Best
Scott
 
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audioferret said:
FE108EZ ... Crossover at about 350 and 2800 My calculations show that it would require only a 1.05L enclosure.

It would make a great midrange, but take advantage of it... XO below 250 & above 5-7k. A ribbon on the top, and the woofer will need fair extension to keep up.

The P13 Scottmoose mentions (there is a special midrange version) is a good driver, but not close to the FE108 (you do need to let the FE108 stretch to get the best out of it.

dave
 
Have a look at the "Leopard" speakers used to test the F1 amp. It used an Eminence Pro driver for the bass, FE168EZ Sigma for the mids in open baffle and Fountek JP3 ribbon as tweeters. There is no reason why the same combination cannot be used with the appropriate crossover with a voltage amplifier.

The advantage of the 168 compared to the 108 is that you could go open baffle and still keep the xover frequency quite low. Also the xmax of the 168 stands in its favour.

If you would like to go boxed, then as Dave has suggested, look to the FE108EZ Sigma.

My FE168EZ Sigmas and Founteks are on their way from Madisound.
 
audioferret said:
Greetings,

How well would the FE108EZ work as a midrange driver in a three-way triamped system? Crossover at about 350 and 2800 My calculations show that it would require only a 1.05L enclosure.

Is there a driver out there with a better midrange around $80?

-The Audioferret

You might be able to get away with a 1 liter enclosure, but I would go bigger if I were you. Mine sound quite good in a 2liter enclosure.
Joe
 
Woofer for MLTL Three Way

For a woofer, I am considering the Scan-Speak 18W/8545k in a MLTL enclosure below the mid-tweeter enclosure. Alternatively, the Vifa XT-WHO09-08 wood-fiber driver seems interesting in terms of cone material and works well in Mr. King's Mathcad worksheets (4:1 ratio, .5lb/ft3).

How close should the impedence and sensitivity of the drivers match? I should be able to work out the sensitivity issues well enouch in the active crossover, but what about impedence?
 
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Re: Re: FE108EZ as a Midrange

Josephjcole said:
You might be able to get away with a 1 liter enclosure, but I would go bigger if I were you. Mine sound quite good in a 2liter enclosure.

I was going to comment on enclosure size in my previous post... let the driver breath.

If you can't get away with an open baffle, look at an aperiodic midrange TL.

dave
 
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Re: Woofer for MLTL Three Way

audioferret said:
How close should the impedence and sensitivity of the drivers match? I should be able to work out the sensitivity issues well enouch in the active crossover, but what about impedence?

As long as you get drivers that match sonically, and you choose appropriate amps with similar sonic signatures, sensitivity & impedance are a no care as far as driver matching goes. Much more a concern when amplifier matching comes into play.

dave
 
audioferret said:
Greetings,

How well would the FE108EZ work as a midrange driver in a three-way triamped system? Crossover at about 350 and 2800 My calculations show that it would require only a 1.05L enclosure.

Is there a driver out there with a better midrange around $80?

-The Audioferret


With the right amplification its the best midrange I've ever heard (better than the paper version, and considerably better than my fe166ESR's):

http://www.madisound.com/cgi-bin/index.cgi?cart_id=9288784.25268&pid=109
 
I love my FE108EZ but.....

I think this is not a good idea.

The manufacturer in order to construct a driver full range, he necessary make many commitments.
Lows and high but not very linear.

You do not use the good things but you use the bad ones!!!!!!.

The FE108EZ does not need a tweeter and is very sweet. That is good. I would make only 2 way and the xver very low ( 100~150 Hz)

best regards Jaime
 
Re: I love my FE108EZ but.....

Jaime said:
I think this is not a good idea.

The manufacturer in order to construct a driver full range, he necessary make many commitments.
Lows and high but not very linear.

You do not use the good things but you use the bad ones!!!!!!.

The FE108EZ does not need a tweeter and is very sweet. That is good. I would make only 2 way and the xver very low ( 100~150 Hz)

best regards Jaime

100-150Hz seems pretty like a pretty low crossover point for this driver. This of course depends on the loading, but this would certainly be too low for me in a sealed enclosure like we have been discussing. Midbass is not the 108's strong suite, not to mention it's lack of excursion to really reproduce 150Hz with any volume. Something like 300Hz seems more appropriate if we are still talking about sealed.
Joe
 
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The FE108eSigma is my single most favorite driver. In a well done horn is will reach 60-70 Hz and there is little need to have a tweeter.

But i have given much thot to using it as the heart of a mostly full range system. To get lots of dynamics & volume out of it and get it to mate with a woofer an XO of 250-300 seems about right to me (i might try to push it as low as 200 Hz to get it doing as much of the range as psossible. It would certainly work as a mid-tweeter, but the extended range of a ribbon is hard to touch... and if the ribbon isn't straining because it is XOed high so much the better. An XO here 0f 7-10k seems right to me (as a ref, Nelson says the Rushmore XO is 8.8k).

As always what you have to battle is integration. Pushing the XOs out on either end allows the FE108 to take over where it shines & gives it some help where it is its weakest.

Any XO is going to have to be completely transparent. probably best to integrate it into the amplifier (ie for hi-pass just shrink some of the coupling caps -- i would recommend a nice SE tube amp or a really good Class A differential tube amp (much harder to get rigt than an SE), a purpose built amp similar or the same with iron optimized for HF on the top too)

dave
 
planet10 said:
The FE108eSigma is my single most favorite driver. In a well done horn is will reach 60-70 Hz and there is little need to have a tweeter.

But i have given much thot to using it as the heart of a mostly full range system. To get lots of dynamics & volume out of it and get it to mate with a woofer an XO of 250-300 seems about right to me (i might try to push it as low as 200 Hz to get it doing as much of the range as psossible. It would certainly work as a mid-tweeter, but the extended range of a ribbon is hard to touch... and if the ribbon isn't straining because it is XOed high so much the better. An XO here 0f 7-10k seems right to me (as a ref, Nelson says the Rushmore XO is 8.8k).

As always what you have to battle is integration. Pushing the XOs out on either end allows the FE108 to take over where it shines & gives it some help where it is its weakest.

Any XO is going to have to be completely transparent. probably best to integrate it into the amplifier (ie for hi-pass just shrink some of the coupling caps -- i would recommend a nice SE tube amp or a really good Class A differential tube amp (much harder to get rigt than an SE), a purpose built amp similar or the same with iron optimized for HF on the top too)

dave

I'm definatly with you on this one. My 108's are in a two way right now crossed at 300Hz and are sounding quite good. I've been pondering recently switching to an active crossover though and getting myself some dipole bass for the low end. With the active crossover I could push the crossover lower with a steeper order crossover, and equalize the dipole bass if need be. I'm still educating myself on active crossovers, but it's definately in my to do list. I had not thought about adding a ribbon tweeter as I've never been dissatisfied with the upper range on the 108's. I've also never spent much time with a ribbon tweeter. Ignorance is bliss I guess;).
Joe
 
Dave slightly OT, but... do you know what happened to John Pomann?
http://www.snippets.org/filters/crossover.htm#ordering
I found the link off of your page and it looks perfect for someone like me. Unfortunatly he doesn't seem to be around any more. At least he doesn't answer e-mails. I would be happy even with a copy of the manual if he is no longer in the selling these kits. Any insights into this?
Thanks
Joe
 
Yeah, the project looked like it would be something that would wear somebody out. Not much room for anykind of profits for him. Hard to keep a hobby/buisness like that going on goodwill alone. Especially if you are a med student... that sounds pretty exhausting. If you find any of the manual or anything else that might be helpfull in designing an active crossover I'ld love to see it.
Thanks
Joe
 
Still Designing

I have made a fomacore mock-up of the speaker design and I think i like it. I was able to catch some errors in design and measurement, so I am really glad I made a small model first.

Has anyone else used balsawood or something similar to simulate a scale model? My next project is to make a small-scale balsa model to see how I like the look of the speakers. I think I want to also try veneering it to see how it works out astheticly.

Also, Would anyone see any issues in using the Scan-Speak 18W/8531G Revelator as the main driver for the MLTL. i have modeled it with Mr. Kings worksheets and I am happy with the results.

Driver/Opening Ratio: 4:1
Line Length: 77"
Lb/sq foot: .6 (Wool)
Offset Ratio: .46

The main enclosure will be 15" deep and 11" wide, 42" high.

I am currently thinking about using 1" Marine-Grade Mohagany Plywood. To get really wild, I also want to experiment with using 1" Sitka Spruce to form the soundboard inside the MLTL. If it doesn't work, I would remove it, but the sound possibilities really intrigue me...
 
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