Thanks to this addictive forum I've built pair of BIBs, Needles and another that I've forgotten the name of.
Anyway, a friend of mine has also become infected and in order to enable him I've volunteered to build boxes for his new Fostex 103ENs.
Can anyone recommend a simple build? They will be powered by a 8w SET.
Thank you so much,
Mack
Anyway, a friend of mine has also become infected and in order to enable him I've volunteered to build boxes for his new Fostex 103ENs.
Can anyone recommend a simple build? They will be powered by a 8w SET.
Thank you so much,
Mack
The simplest is the 6-liter factory bass-reflex cabinet, tuned to ~80Hz. If you mount the boxes on a shelf (i.e., near the wall), you won't need BSC. They are an excellent match for SET and 8 watts is plenty (I'm driving them with just 2 watts and it's totally workable for me.)
P.S. If you calculate the port so that it consists of several 1" or .75" holes, on the back, you can actually get away with zero stuffing. I used Unibox but almost any program will work. (The small size of the holes plus the rear location serves to low-pass the ports to a surprising degree.)
P.S. If you calculate the port so that it consists of several 1" or .75" holes, on the back, you can actually get away with zero stuffing. I used Unibox but almost any program will work. (The small size of the holes plus the rear location serves to low-pass the ports to a surprising degree.)
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Cool, there's a diagram which comes on a sheet of paper in the driver box.
I should have mentioned I'm using a sub. The speakers roll off at 80Hz, then there's a room mode at ~70hz, and the sub comes in around 60Hz (a not very effective way of dealing with modes, because the bass response still varies quite a bit as you move around the room).
The FE103En are amazing for the money, but also (cost aside) still amazing because they are basically a tweeter with pretty wide dispersion that can play down to ~80Hz. Tone is great, sound is pure and clear, exactly what most SET people are looking for (all the usual caveats apply of course).
I should have mentioned I'm using a sub. The speakers roll off at 80Hz, then there's a room mode at ~70hz, and the sub comes in around 60Hz (a not very effective way of dealing with modes, because the bass response still varies quite a bit as you move around the room).
The FE103En are amazing for the money, but also (cost aside) still amazing because they are basically a tweeter with pretty wide dispersion that can play down to ~80Hz. Tone is great, sound is pure and clear, exactly what most SET people are looking for (all the usual caveats apply of course).
Single Driver Website
and MJ Kings compact basshorn, there is a detailed thread here about that horn/pipe using a 4" Tangband driver
and MJ Kings compact basshorn, there is a detailed thread here about that horn/pipe using a 4" Tangband driver
If you want simple, then a BR is likely to be about the easiest option, although I have rather strong reservations about the design Fb of the Fostex box -not the best alignment I've ever seen. Nor am I entirely certain what is being referred to above about multiple smaller holes 'low passing' the port, which sounds like a new type of physics to me. 
If you have high aspect ratio vents, the friction will make them increasingly resistive and eventually shift the box toward something akin to a leaky sealed alignment (what's usually called aperiodic, though the definition isn't strictly true). This will not in my experience obviate the need for some internal damping -for example, its effect on possible unwanted internal reflections coming back out through the cone is roughly equivalent to the square root of jack.
FWIW, if you dropped the FE103En into the 6 litre box Fostex publish, given that you say it'll be on the end of a SET amp, I'd be more inclined toward tuning it to ~75Hz. The output impedance of most SET amps varies between about 2.5ohms & 4ohms; with the stock tuning you get a considerable peak at Fb. This sounds impressive initially, but quickly becomes tiresome, especially if room gain lifts it still further (likely in many cases, especially if placed near boundaries). Going for a 75Hz Fb should provide slightly better damping on the bottom end, and also prevent the box unloading quite as much since as a simple reflex enclosure, there's little to control excursion below the tuning frequency. Won't sound quite as impressive initially, but likely easier to listen to over the long run.
The Zigmahornet has a decent midband given that there's just about no baffle, but is poor on the bottom end -step-loss is something chronic unless rammed right up against a wall, and it's tuned way too low IMO. Frankly, I wish it did work since they're rather attractive boxes in their own way, but there are better boxes out there.
GM's ML-Voigt if memory serves was for the defunct RS 1197, the 103 might go in, but I don't have time to check right now to see what the behaviour will be like.
The mFonken is a different box type altogether, being closer to the type of leaky sealed box I mentioned above. It won't put out much LF gain, but it's not designed to; it'll be fairly damped on the bottom end, but a good match to a couple of subs.
Hope some of that helps.
If you have high aspect ratio vents, the friction will make them increasingly resistive and eventually shift the box toward something akin to a leaky sealed alignment (what's usually called aperiodic, though the definition isn't strictly true). This will not in my experience obviate the need for some internal damping -for example, its effect on possible unwanted internal reflections coming back out through the cone is roughly equivalent to the square root of jack. FWIW, if you dropped the FE103En into the 6 litre box Fostex publish, given that you say it'll be on the end of a SET amp, I'd be more inclined toward tuning it to ~75Hz. The output impedance of most SET amps varies between about 2.5ohms & 4ohms; with the stock tuning you get a considerable peak at Fb. This sounds impressive initially, but quickly becomes tiresome, especially if room gain lifts it still further (likely in many cases, especially if placed near boundaries). Going for a 75Hz Fb should provide slightly better damping on the bottom end, and also prevent the box unloading quite as much since as a simple reflex enclosure, there's little to control excursion below the tuning frequency. Won't sound quite as impressive initially, but likely easier to listen to over the long run.
The Zigmahornet has a decent midband given that there's just about no baffle, but is poor on the bottom end -step-loss is something chronic unless rammed right up against a wall, and it's tuned way too low IMO. Frankly, I wish it did work since they're rather attractive boxes in their own way, but there are better boxes out there.
GM's ML-Voigt if memory serves was for the defunct RS 1197, the 103 might go in, but I don't have time to check right now to see what the behaviour will be like.
The mFonken is a different box type altogether, being closer to the type of leaky sealed box I mentioned above. It won't put out much LF gain, but it's not designed to; it'll be fairly damped on the bottom end, but a good match to a couple of subs.
Hope some of that helps.
Hi Scott,
Thank you, I'll try improving the tuning on the next iteration, although it seems pretty on already. For this very humble build, I didn't use the exact Fostex dimensions. I used a 6.6 liter ~golden ratio box tuned to 80Hz as confirmed by an impedance sweep. Just for fun, I used The Edge to offset the drivers (mirrored pair). I didn't see a peak at Fb but if so, I will re-size / re-tune (these boxes were intended as junky prototypes but they sounded much better than expected).
I know nothing of physics but the four .75" rear-mounted holes offers less comb-filtering of midrange leaking out of the port, or so goes Dr. Miyagawa's rationale. The holes are drilled into a solid block of wood inside the box (the so-called Miyagawa vent). (I will post measurements when I can get back the laptop which has the Windows software).
Surely these boxes can surely be improved further. I'm looking to put a huge roundover on the edges if only for fun, can't hurt. If they aren't yet optimal, at least they are incredibly good, much better than anything I've had to date but I don't listen to rock at all.
Thank you, I'll try improving the tuning on the next iteration, although it seems pretty on already. For this very humble build, I didn't use the exact Fostex dimensions. I used a 6.6 liter ~golden ratio box tuned to 80Hz as confirmed by an impedance sweep. Just for fun, I used The Edge to offset the drivers (mirrored pair). I didn't see a peak at Fb but if so, I will re-size / re-tune (these boxes were intended as junky prototypes but they sounded much better than expected).
I know nothing of physics but the four .75" rear-mounted holes offers less comb-filtering of midrange leaking out of the port, or so goes Dr. Miyagawa's rationale. The holes are drilled into a solid block of wood inside the box (the so-called Miyagawa vent). (I will post measurements when I can get back the laptop which has the Windows software).
Surely these boxes can surely be improved further. I'm looking to put a huge roundover on the edges if only for fun, can't hurt. If they aren't yet optimal, at least they are incredibly good, much better than anything I've had to date but I don't listen to rock at all.
quite different flavours - I'd describe the 103 as "classic", while the entire WK series as more "contemporary" - well detailed throughout the mids to low top end, and, depending on size, quite possibly a bit too bright / forward for some ears (not mine) - but not to the same degree as the FE127
for nearfield or FAST use the 85WK is an eye-opener indeed - just don't try to fill an auditorium with drivers this size
so far the only enclosure in which I've heard the 105WK is the Woden Vampyr - with "optional" suprabaffles - I could certainly live with the sound with appropriate bass support, but the aesthetics are just idiosyncratic enough to fail the "Sue" test (frankly, I sometimes wonder how I passed that one
)Cal - that's for you buddy
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The wk units aren't necessarily high tech (they're not), they're just different, largely filling the gap left when Fostex discontinued the old shielded FExx7E range, along with pulling double-duty as the successors to the FFxx5K range. As ever, 'better' will largely depend on personal priorities and opinion, so YMMV on that score. I'm rather disappointed with the wk range TBH, but they're there, and they could be worse.
Re mating to a suitable woofer, yes, should be fine providing you address the impedance and any breakup modes in the bass-driver's stop-band.
Re mating to a suitable woofer, yes, should be fine providing you address the impedance and any breakup modes in the bass-driver's stop-band.
I might be able to come up with a box your good lady would prefer. In fact, I've been pondering a couple of ideas of late that might be of interest / use.
best of luck with that - she's all over the FB thing, but "special interest hobby forums? honey, those are cute, but my time's too valuable for that "What, I don't pass the Sue test either? Get her on the forums here, I wanna talk to her.
edit: for example, on one of the shore excursions on a recent cruise ( Georgetown, Grand Cayman) we were strolling around the touristy part of waterfront immediately opposite the tender dock and after a quick poke into the gift shop on the lower floor of MargaritaVille, it was "Oh, just T-shirts and mugs, dear - I'll pass on the lounge upstairs for a Cheeseburger in Paradise" - they probably didn't have any vegan on the menu anyway
never, although I did have something snarky to say, but (for once) thought better of it
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I think of the FF105WK as more suitable for smaller and less complicated bass reflex and Fonken style enclosures and the FE103En as more suitable for larger and much more complicated horn style enclosures to extract more bass while gaining some efficiency. Someone desiring a simple small box would probable be better off with the FF105.
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