Thoughts on the F120A or FE108ES2?

I was looking around on the web and am wondering about these two drivers. As you probably know, I currently have the 168E Sigmas, which seem to be really nice. But, I do like to be impressed with new drivers from time to time.

Low end isn't really a concern with my future plans, so I'm just wondering if anyone has heard these drivers and what they think of them. Also, if you have any comparative thoughts to the 168, 108 or similar, I'd appreciate it.

Thanks much!
 
No thoughs on these drivers? I had hoped to get some response, even if it's just forecasting.

Both drivers appear to have very substantial magnets, with the F120A being a bit of an older design, and the 108ES2 being newer. The curve for the 120 appears very smooth, while the 108 is a bit more choppy. I'm wondering which may be smoother (I'd guess the 120 with the Alnico) and which may reproduce more detail. Also, will one offer more upper frequencies than the other? I'd imagine the mids on both would be wonderful, to say the least.

If you have any thoughts to share, I'd love to hear them. Thanks much!
 
Hi,

I've heard only the best about both (but also that f120A will need helper tweeter), but I would'nt expect them sound MUCH different from your fe168ez...(especially the FE108ES2) Maybe you can look at something like Visaton B200-price is lower and from what I have read it seems to be better than F200A...

Good luck Martin
 
Layne,
Both of these drivers are pretty high end. I doubt you will find somebody who has heard both, much less somebody who has spent a lot of time with both to give you a reasonable comparison. Where are you finding info on the new 108es2?
Obviously since I haven't heard either driver or even seen the specs for the 108es2 take my advice with a grain of salt. However the f120a is a fairly low effeciency driver (if memeory serves) most of the fostex "special" models add a larger magnet which would lower the Q and slightly raise effeciency (assuming everything else is similar). If you are looking to build a 2-way I would think the 108es2 would be my choice (assuming my mirad of assumptions are correct). My two way with the regular 108 if fairly ineffecient all thing considered. A lower Q would probably lead to more detail/resolution along with the possibility of more dynamics due to higher effeciency. All this would work quite well with a low Q pro woofer.
Joe
 
Joe

I thought I might hear from you. Eifl Japan has the 108ES2 listed in their site. It's a pricey little beast, but could be worth the effort. I know you speak highly of the 108 in your system, so I thought this could be fun to play around with. Actually, I've read a lot of good things about the 108. And since I'm not worried about low end, it could make for an interesting design.

I'm hoping to be able to build the woofer portion of the cab on it's own, so I can try different drivers above, as I've got a couple nice ones to try. I'd imagine the simple crossover would work for any of the drivers, (no guarantee though) so it could make for an easy switch between cabs. Or, I may go with OB for the full ranger to open things up. We'll see, it'll take some experimentation. And time, which I don't have right now.

I still have to get through your email, thanks for sharing your thoughts.

Layne
 
FE108ESII is a high class horn driver and never was exported from Japan.
F120A is not a horn driver.

I have a FE108EZ hornm and I like very much, but in very complex music it is not very satisfactory.

For that reason I buy a pair of FE168EZ recently. They have more power ( 80w versus 24w) and sensitivity (94dB versus 90dB).

Will be the solution?
Best regards Jaime
 
Strange!

Jaime,
I don't know if the answer is in a horn "subwoofer" because a horn subwoofer does not exist. I mean a horn that will go below 20Hz.

From my experience, both 108 and 168 are not satisfactory with complex music, and I think that the explanation is in the design of the driver.

Don't get me wrong, these are very well designed, problem is they both have no excursion capability, so when they try to reproduce large amplitude signals (bass) along with a multitude of mid and high frequency information, the mids and highs are modulated by the excursion of the driver, as the driver is unloaded by the horn below cut-off freq.

I am thinking of high-passing the 108 at in-between 60 Hz and 100Hz (for a start), so signal that require some excursion won't reach the driver. The 108 horn (as well as the 168) are really designed to provide low mids reinforcement with an upper cut-off around 300 or 400 Hz.

The low frequency content (from 40Hz to 80 or so) will be fed to a pair of 15 in. pro-drivers in bandpass-horn hybrids (adjusted for sensitivity match), and everything below 40Hz will just be removed by a brickwall filter (there is nothing below that frequency in acoustic music anyway).

I do not know if this will work, but I will surely report back!
 
Still working on calculation!

Well, I don't know if the horn-bandpass hybrid will see light, from calculations, a pair of (BIG!) Onken enclosures with 15 inchers is the perfect match on paper:
similar efficiency (around 94dB)
very flat response from 40Hz (30Hz at -6dB)

Probably a good candidate for a 1st order Xover at around 100hz, which should relieve the FE108EZ of most of the excursion requirements...

Will see. I'll get the 15 in. driver next week and start on the Onken cab...
 
robertG

I understand the difficulties of the little FE108EZ.
It has sensitivity 90 dB and Xmax = 0.28mm
But the FE168EZ has 94,5 dB sensitivity and Xmax = 1.6mm.
It works comfortable????.

When I said subwoofer I was thinking about a low bass driver.
The mid bass box probably is a good idea. But I believe that it must obligatorily be horn box.!!!!

An old article of Jean Hiraga in L'Audiphile magazine shows an idea that I like. But it would be necessary to calculate correctly.
http://www.geocities.com/dbr_audio/Subwoofer-Hiraga.pdf (fig 5)

best regards Jaime
 
Jaime,

The problem I found with the 168 is the beaming at upper-mid and high frequencies, and most of the sensitivity difference (compared to the 108) is there.

The peak at 7kHz is especially difficult to live with, and the only way to tame it is (apart from ear plugs) is to use a notch filter that will also reduce efficiency, so the difference in overall eff. is not that much.

True, the X max of the 168 is greater, but on the other hand, there is distortion (especially modulation of higher freq.) the minute there is cone movement. Since this excursion is there only for bass output and since bass output is (slightly) insufficient anyway, I guess the only sensible solution is to use one or the other as a low-to-high driver and using a dedicated bass driver(s) for really low frequencies (30 to 80hz).

I agree totally with the fact that a horn bass module would be perfect (provided sensitivities are matched). But to keep things simple and acceptable, I also think that a really large pro driver with something like 96dB eff. at 30 or 40 Hz, 15 in. driver might be "fast" enough to respect the impact ability of the sigma drivers.

I'm a big fan of Jean Hiraga and I read (and re-read) everything he wrote for La Nouvelle Revue du Son back in the 70s. What he refers to in his article is essentialy bandpass enclosures, which are OK to reproduce bass, but might not have enough BW to cover from let's say 25Hz to 80 or 100Hz (almost two octaves).

Problem with the horn-bandpass enclosure I calculated was a peaking sensitivity of around 110 dB/w/m at around 150Hz, thus needing a big (or active) filter to chop everything over 94dB from 40Hz or so to 100Hz, with brickwalls below and above the frequencies.

A very large reflex or Onken cabinet could be quite easy to optimize for around 94dB eff. from 30 or 40Hz all the way to 100Hz (just a simple low-pass in the circuit).

Ah, choices, choices, decisions, decisions!
 
Nice that others are chiming in. I think at this point, I'm going to stick with the 168 for now. I have to admit, I don't find any problem with beaming in my system. So not a huge concern for me. For some reason, I'm not hearing back from Eifl Japan, so that puts the stop to that driver, for the time being anyway.

I am going with a bass driver of some sort, similar to JC, though yet to be decided. I've thought of open baffle or a 12" pro sound driver ina box. I would prefer a 15", but the amount of room it takes becomes an issue. Also, too much bass would be an issue in my apartment.

Also, once I get things put together, I may try a tweeter of sorts for the upper end. Considering a ribbon or possibly even a Jordan JX53, if it would work. I have some T90as on a shelf, so I will proabably try those first, though not sure how they would perform as more than a super tweeter. (may roll the driver off a bit early to smooth out the treble, more of an idea right now than reality)

I'm considering the Bass Zilla plans as a starting point. Just something to work with.

Anyway, while the build isn't going to happen yet due to an exteremely busy schedule, I thought I'd update on my thoughts.