These things are so cheap relative to finished comercial offerings! I 'm so happy with my FE168 BIB that I'm wondering if there are other drivers out there that are "better". I've got the bug and want to build another pair.
Better depends on what your looking for. More focus? Better Dynamics? Detail? Smoothness?
Your pretty close to Planet 10, so his modified Fostexs are a good place to start. There are also the Lowthers, PHY-Ps, and the Feastrex. Let's not forget the Fostex 138es-r that has its own thread. Of course each has it's strengths and weaknesses. It all depends on what your looking for.
I'm sure others that have heard some of these will chime in too.
I've tried many (many, many) fullrange drivers in my lifetime(Various Coral, many fostex, EV, Fertin, Supravox, Visaton, RS, Goodmans, Manger, Philips, Hemp, etc...).
To me, there is just something about the Lowthers (DX-4, DX-3) that is absolutely incomparable. The Lowthers are very difficult to get properly loaded, but when you do, Wow oh wow.
My current Lowther faves are the DX-4 in Big Fun Horns, Beauhorns, The Academy, etc. I will soon be building the DX-3 All fun horn for myself.
I have listened to a few of the Fostex drivers, I own four different models right now. I also own a few pairs of Lowthers and in one on one comparisons all of the Lowthers better the 6" and 8" Fostex drivers that I have heard. I agree with Daze that the DX4 and DX3 are excellent. I also really like the PM2C and PM6C and consider them both a bargain. I am not such a big fan of the PM6A or PM2A drivers.
I too am a lowther fan, i orgainse some meets in the uk
i see lots of fostex based speakers demo'd
i don't think they come to close to the better lowthers, the exception being the low cost of them
over the last 10 years i've build a few back loaded horns
but now use ex4 in OB with some vintage goodmans on bass duties
its the best sound i've had ... so far
Its quite hard to judge a speaker on its own
the amplfier is so critical to getting the best sound..
my blh's needed armophous core outputs to ensure the horn did not sound too coloured.. but in saying that, I seemed to get a sweet sound with horns without too much work on the amp..
the baffles seem to show weakness in the amps more readily
and its easy to blame lowthers when the amps and horns are not up to the mark
an 'average' or even most 'good' amps.. will not show what a lowther is capable of in my experence..
but i'm still very much learning...
What Goodmans drivers do you use for bass duties Steve, the 12 inch Audiom 60? I have a pair of those in 15 watt/15 ohm and consider them incredible. They work to 20 Hz in the right enclosure up to 5 k or so, are efficient and very smooth without honk or beaming.
i use the lowther full range but rolled off at the bottom by the baffle shape/ size
the goodmans are 301 and 61 close together for coupling,and in ob.
they go down to the mid 30's no trouble, they are rolled off above 1000 hz ...
and do that with out any box sound..
the only crosover component is one inductor on the goodmans
one goodmans on its own per channel was not a balanced sound
using 2 x12" is a very good in my view, they are also tighter than most 15" drivers i have heard..
My Lowther OB system has gone a completely opposite path as Steve followed. I have two high efficiency 15" woofers crossed over with a low pass filter at 200 Hz using an active digital crossover. The Lowther is high passed, also at 200 Hz, so it does not see any of the low frequencies. I use a pair of 200 watt solid state amplifiers for both the four woofers and the Lowthers. You can play this system really loud and still have to touch the drivers to make sure they are actually moving. Two very different approachs to a Lowther OB system.
Martin, i tried various cross over arrangements( although i'm not much of an expert at them). and found they spoiled the sound somewhat..
i believe in using 'simple is best' from an electronic point of view
and not being dissapointed so far, but i'm constanty trying out mods to get more performance.
at the moment I drive mine with one, two watts /channel home made valve amp
its a 1930's 2P output valve driven by a early 30's mesh 1 watt output valve into a pair of Pieter's tribute amourphous transformers.
it does 105 dbs peaks
the bass is may be not the deepest, but the deepest sounds i have heard do not sound as true as this,
It's the speed and tightness of the bass that sounds so good.
getting the amp right makes as much difference to the sound as the speakers do, the best of the early valves in my view are still ahead of any thing else in the quality stakes.
I will never go back to horns or boxes
I collect old valves and use px4, px25, british vt25's(det25),have 300A to build with, and many (1000's!) more,
Your using eminence drivers?,... that will have given you a challenge to get them to integrate with the lowthers in they way mine do.
my experence of the goodmans vs eminece is like comparing fostex to lowthers, many cannot tell the difference..
and many say it does not matter in the bass, i do not agree.
like your set up, at high levels you cannot see any of the drivers move, you can only feel them slightly viberate....
i friend of mine who built their own equipment in a 70's pop group used a wall of 301 and 61's, he would not use the 15" versions... and he was the bass player... the differences are subtle, but they are there.
1. Increasing the driver diameter from 6" to 8" will improve the bass and mid bass output strength (or weight to use audiophile speak) at the expense of perhaps a little high end extension.
2. Upgrade from a Fostex to a Lowther driver, I believe it is an upgrade.
But I need to say I have not heard your specific Fostex driver. At the time I was making comparisons between Fostex and Lowther drivers I was using the FE-164E and the FE-208E Sigma. This was about 5 years ago. At that time the differences were obvious, my son who was 11 or 12 had no trouble describing the differences. Basically the Lowther sounded like a curtain had been removed between the listener and the recording. The Fostex sounded a little muffled while the Lowther was crystal clear. If you had not heard the Lowther the Fostex would have been easy to live with as I already had for a few years.
The DX3 is a great driver and can work well in a wide variety of enclosures. It is sort of a middle ground between the PM2A/C or DX4 and the PM6A/C or DX2. A good compromise and probably the driver I use most often. As I stated above, don't discount the PM6C which for the price is a really nice entry level Lowther.
You can find the measured T/S parameters of my collection of Lowther drivers on my site under the General Speaker Related Articles link.
Another good person to ask about the Fostex/Lowther trade-offs is Bob Brines. He has built speakers using both makes of drivers and has probably heard a few more of the newer Fostex drivers.
The cones are very thin, you can see light through them. Obviously you want to take care handling them and they could sustain damage if you screw up. But any driver cone can be damaged if you are not careful. How many dome tweeters get dented or pushed in and ruined?
I have always run my Fostex and Lowthers using a 200 watt SS amp. I have accidently shut the active crossover off before the amps resulting in a pulse and very loud thud. I took the speakers to a audio meet and had a home made amp go unstable with some form of grounding problem which produced a very nasty noise. I have played the speakers at fairly loud volume levels on more than one occasion. No problems.
I have never damaged a Lowther driver. I am sure I could dream up a way to damage one, but that is also true of many other types of drivers. I guess I would say that the drivers are fragile and delicate, but they are not frail. Take care of them, be careful, and I don't think you will have a problem.
Weren't your 208s the older non 'E' Sigma model Martin? The ESigma is a big upgrade on the earlier driver, although it needs a good supertweeter as it's a WB, rather than an FR unit. Beats the Lowthers in the LF, although the latter have more detail & upward extension of course.