Fostex fe108 eSigma in OB ?'s

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I did a search and came up with many ideas and directions, but nothing concrete.. I thought I had seen at one time the 108 used in an OB designed by MJK, but it was the 103 it would appear.. A few have had good luck using the 108, but they go back a few years now..

So I guess my question is; Has anyone or is anyone using the 108 on a OB, or is there already a worked out diy plan for said system? I did read that some said the 108 is louder than the Alpha 15'' when used together on a OB, and it needs padding down etc..

Thinking on giving the OB style a try to hear the flavor that many enjoy with them, and how the OB with 108's will compare to my inverted BIB's.. I'm figuring from all I've read, that an OB with 108's done properly should give a nice bit more overall SQ, compared to the inverted BIB cabs?
:)
 
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I built a 2-way fe103e over an Alpha 15 in an H-Frame from Martin King's design and I haven't had any regrets- even though the H-Frame drops the Alpha's SPL ~4db. The 108eSig is only listed as 1db hotter than the 103e. There have been a lot of successful variations on the top driver in this set-up done by a lot of different people on this forum.

If you have the real estate to do OB, then I encourage you to do so. I've been living with these in my living room since last Dec and they still give me goose bumps.:) Enjoy the ride!
 
Hi DaveCan!

To me, the Fostex 4" drivers I've tried have an Fs that is just a tad too high for an upward-firing BiB (so I think you did right by inverting them). But for bone-rattling bass, I think your idea of OB with woofers can't go wrong.

If you use an active crossover, you won't have to pad down the 108. The 18" Goldwood GW-1858 is not much more than an Alpha and I heard some recently (Mr. John Busch had two per side at LSAF and it was incredible and mind-altering).

These are the same woofers popularized by Martin King in his Jordan project, and they have a lower Fs and (obviously) more displacement than the Alphas. They are cheap enough to do two per side, which I hope to do at some point with the older FE108-Sigmas (the ones without the fancy cone / surround, which are just sitting in the garage.)

(I'm using a very cheap used active crossover.)
 
Thanks guys..

I read that whole thread today, all 51 pages of the Jordan/Goldwood OB.. I have seen that thread many times but never bothered to look at it, as metal cone full range type drivers have zero appeal to me, same with metal coned or kevlar woofers, mids etc.. Having said that, I was very surprised at all the good info and ideas there, and also surprised at how many different drivers were talked about other than in the thread title etc..

Godzilla's glowing reports of when he tried out the Alpha H frames really got my attention!.. And of all the different drivers mentioned in that thread, there was one page where the 108ez were talked about briefly.. It sort of surprises me (well not really considering) that the 108 seems to almost be forgotten since all the 126 hype started some years back.. The 108 e sigma is a really nice sounding driver unmolested even, and they get better as the hours work on them...

I had thought for sure I had seen an OB by MJK done for the 108, but that must have been the 103's that I had mistaken it for..

I knew right from the get go when I did my BIB's to make then inverted, for that very reason you mentioned Robert.. Got my clue from the late TC's take on the 108 BIB, and I in no way imply that I even got anywhere close to his application, or at all believe mine to sound anywhere close to what his must have been like.. They did turn out pretty good though considering my skills and woodworking abilities, and sound nice enough, although certainly not without some troubles. They aren't perfect for sure, but for such a simple build, wow! .....

Thanks for the encouragement givmhoof, I surely will give it a try, and expect from all that I've been reading about them, that I'll probably park my BIB cabs for awhile :)

Anyhow curious to get the 108's out of the BIB's where they have resided since installed for the first time, and give an OB a shot... Then from there, on to Altec/GPA when funds permit :)
 
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I use the FE108EZ's in the MJK open baffle design. They sound pretty good to my ears although I haven't tryed any other drivers to compare. I did have to pad them down a bit though.

I'm using a passive crossover although if I did it again I'd probably go active, as the bass, whilst reasonably good, still leaves a bit to be desired.

An externally hosted image should be here but it was not working when we last tested it.


Uploaded with ImageShack.us
 
Nice, thanks for posting the photo wixy and for your impressions.. Have you considered to maybe try the H frame method on the woofers, to see/hear if the low end picks up some? Could be an easy tweak to try possibly by just adding on to the front and back of your baffle, and snug them up as halves just to check it out..

How do you like your OB's compared to other types of cabs you may have owned or enjoyed previous ?

:)
 
I haven't thought of trying the H frame, but I might rig up something removable and give it a go.

The only speakers I have owned previously (and still do) is a pair of Fostex FE206E's in back loaded horns. The ob's provide a more spacious and cleaner sound with better mids/highs and more natural sounding lows. The horns sound punchier and rock harder. Overall though I prefer the OB's, for the price they perform well and very listenable.

However, similar to you, I'm just saving my pennies for the GPA Altec 604's which I believe are more likely to be a speaker that I keep in my system for many many years.
 
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Well
here's a picture of my own open-baffles.

An externally hosted image should be here but it was not working when we last tested it.


These use the FE180ES as a tweeter, taking over at the top end from where the Goodmans Axiom 401 below starts to roll off.

Believe it or not, the FE108ES makes a fine tweeter.....and being a cone driver, open at the back, gives dipole radiation at HF
to match the dipole patterns from the Axiom 401 and the actively-driven Eminence Delta 12 at the bottom.

IME OBs perform best if the low end is actively driven. The Delta 12s use 50W plate amps cannibalized from a pair of old Ruark subs I had.

Steve
 
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Serenechaos, do you think you may revisit an OB style cab again someday?, or if not, maybe you could say how they were lacking for your ears, room, application etc.

Steve, thanks for the photo :)

I've been using my 108's rullrange for the last 3-4 years, and I agree they have a nice sounding top end also..

I know adding some low end definitely kicks the perceived sound of these little drivers up a notch.. One time a few years back I added a pretty decent sub, and was really surprised at the difference in overall sq while still running the 108's fullrange .. Anyhow I think I will go the H-frame method as the price of initiation is not so bad at all, and I already have my 108's...

I guess one cannot run the 108's fullrange on the OB can they if only using a few watts of power? Can the woofers still function well both hooked up mono? I only have one sub amp the Reckhorn A-400
 
I use the FE108EZ's in the MJK open baffle design. They sound pretty good to my ears although I haven't tryed any other drivers to compare. I did have to pad them down a bit though.

I'm using a passive crossover although if I did it again I'd probably go active, as the bass, whilst reasonably good, still leaves a bit to be desired.

An externally hosted image should be here but it was not working when we last tested it.


Uploaded with ImageShack.us



Looking at these OB's again, I was thinking; Rather than mess up the clean look of the flat front of the baffle by adding the front half of an H-frame, could an open box be added only onto the back of the woofer section instead, to provide more low end benefit whilst still retaining all that is enjoyed from the OB low's?
 
Serenechaos, do you think you may revisit an OB style cab again someday?, or if not, maybe you could say how they were lacking for your ears, room, application etc.

No, I didn't like the OB effect.
I read of many people that did like them, and thought I'd try them; did w/ several drivers & rooms, then heard many more (linkwitz, etc) @ RMAF the last few years.
I don't like the way that out of phase, delayed wave looses detail, blurs the sound, "muddys" things up as my wife says, even in well damped rooms.
Just our ears, many seem to like them, and they are an easy build.

I just posted because although while I didn't the 108s in OBs,
I did like 108s in OBs better than any other drivers i tried.

If I were to try OB again it would be w/ 10" Tannoy Reds.
They have a really nice tone just sitting on the floor.
 
Scott, thanks for the pointer I didn't think of it that way, what I was saying is basically the U baffle approach, makes sense to me now :cool:

Serenechaos, good to read your impressions and thanks for sharing.. Neat to see that you enjoyed the 108's compared to others etc..

Jim, nice project!! Looks good and thanks for pointing me to the link..

For a stupidly simple project (we are talking me after all lol), what do you guys think if I just run my 108's on a OB like Jim's or Wixy's style, and leave them unfiltered as they are now and always have been in my BIB's? I only have a few nice clean watts on tap and don't listen real loud or anything. Then I would run the woofers (probably the Alpha's) paralleled to my Reckhorn mono sub amp, and play with the sub amp filters as required to achieve a nice sq? I guess I'm wondering if I really need to high pass the 108's still to keep them from smoking?
 
...what do you guys think if I just run my 108's on a OB like Jim's or Wixy's style, and leave them unfiltered as they are now and always have been in my BIB's?
I only have a few nice clean watts on tap and don't listen real loud or anything. Then I would run the woofers (probably the Alpha's) paralleled to my Reckhorn mono sub amp, and play with the sub amp filters as required to achieve a nice sq? I guess I'm wondering if I really need to high pass the 108's still to keep them from smoking?

That's all I did; was enough to see if you like them / or can't stand them.
 
>>> the 108 seems to almost be forgotten since all the 126 hype started some years back.. The 108 e sigma is a really nice sounding driver unmolested even, and they get better as the hours work on them...

I wish i bought a pair of 108s when they were selling cheaply from Ed when he began using the also great 126.

Even tho i am enjoying OB sound at the moment my BIBs have not been dismantled. I look forward to enjoying them again in the future.

Also, i think the H-frames in my room offered more room filling bass than the OB alone... although neither is lacking bass LOL. The H-frames FILLED the room with bass and could be overwhelming at times. The best bass i ever heard in my room was with the H-frames.

Godzilla
 

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Agreed, would have been nice to have gotten a pair of 108s for spares back when Ed was letting them go so cheap!
And after a lengthy run-in, I like them much better than painted 126s.

I don't know why the Swans haven't caught on though.
Maybe just a preference thing, but they're the only single driver I've kept any amount of time, I like them far better than bibs, or OBs (regardless of drivers).
Although like OBs, I sometimes use them w/ a ribbon crossed @ ~10K, and/or tapped horns coming in around 60Hz.
You can't hear the tapped horns unless you unplug them, very seamless, and everything can run off the same amp.
 
Guess where I got my 108's:D Yep, from Ed's blow out sale a few years back at a nice fair price..:cool:

Jeff, nice to hear about those H-frames! Sounds like a worthy experiment, and the drivers are certainly reasonable in price to get on board with and try out for size.. I also plan on keeping my BIB's around.. They are the first diy build I had done other than a few sub's, and proved that a lot of good sound can come from a very simple build ("disclaimer"- that is after all you guys had worked out the dims, I just built the dang things).. They may not be perfection to the 9th degree but have provided me with many hours floating on the music (no intoxicants even lol)

Serenechaos, I wonder if an experiment for you could be to try the OB approach as before, but add a few thick layers of say acoustical batting insulation over the back of the drivers to absorb some sound.. It would still be OB, but perhaps that could settle some of the frequencies bouncing around that offend the sq to you? I've read before that your not a fan of OB and thought about that idea but never thought to state it till now.. I've never heard an OB myself so I cannot comment, but seems like a fun experiment to try and I've already got most of the parts etc.. I think if the same happens to me as with you and your wife after listening to them, I may try some type of absorbing trick while still basically keeping it an OB type approach, then if still a no go at least it wasn't a pricey gamble and worth the learning and experience etc..
 
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frugal-phile™
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Guess where I got my 108's:D Yep, from Ed's blow out sale a few years back at a nice fair price..:cool:

I got 3 sets that way -- but 2 of the sets needed to have dustcap ectomies, one because it was damaged, the other because we needed to excise a botched Ed experiment. Still got to EnABL one of those sets and flog them cheap.

dave
 
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