Does anyone have any real world experience with the Fostex FE163eN-S? I'm surprised there is very little search results on the net for these. They seem popular in Japan, but not here.
I just got the last pair in Canada from Solen. Reg $280ea on sale for $180ea.
Fostex "this unit that has been developed based on all the skills that Fostex cultivated in the past."
From what I can gather,these are a hot-rodded version released in 2011, very flat freq response, and a claimed cutoff freq Fc of 21hz using the supplied Fostex rear loaded horn plans. I thought small horns are restricted from going low, am I reading it wrong?
They have the 168 sigma round basket but the similarities end there. Ripple surround, and very powerful magnet, (1,100gram magnet, QTS .23, 8.2 BL vs 168sigma's 721gram, .26, 8.0BL)
I just got the last pair in Canada from Solen. Reg $280ea on sale for $180ea.
Fostex "this unit that has been developed based on all the skills that Fostex cultivated in the past."
From what I can gather,these are a hot-rodded version released in 2011, very flat freq response, and a claimed cutoff freq Fc of 21hz using the supplied Fostex rear loaded horn plans. I thought small horns are restricted from going low, am I reading it wrong?
They have the 168 sigma round basket but the similarities end there. Ripple surround, and very powerful magnet, (1,100gram magnet, QTS .23, 8.2 BL vs 168sigma's 721gram, .26, 8.0BL)
An externally hosted image should be here but it was not working when we last tested it.
These (and the 20x version) are beautifully crafted drivers.
Lack of a full suite of T/S parameters have slowed enclosure development. The best of the Fostex recommended horns are mediocre at extracting the most out of them. There have been a few installed into the Woden horns with very good results reported. You would be interested in Victor.
I have had these in my living room with the older FE166eSR installed. Very good.
dave
Lack of a full suite of T/S parameters have slowed enclosure development. The best of the Fostex recommended horns are mediocre at extracting the most out of them. There have been a few installed into the Woden horns with very good results reported. You would be interested in Victor.
I have had these in my living room with the older FE166eSR installed. Very good.
dave
Thanks for the info Dave,
I know generally speaking, fostex plans are less than ideal, but i would hate to brush this specific plan off because of this.
#1. I was planning on using hornresp to calculate a BLH, but are there parameters missing to do this like you mentioned?
#2. I'm fimiliar with double back horns like the Victor, but could never understand why a design like this would be better than a single, longer horn path. I could see some db gains in the mid bass, but if were going big, why not go for extension instead?
#3. I've built your frugal horns, so just want to say thanks Dave for all you have done in the DIY community.
I know generally speaking, fostex plans are less than ideal, but i would hate to brush this specific plan off because of this.
#1. I was planning on using hornresp to calculate a BLH, but are there parameters missing to do this like you mentioned?
#2. I'm fimiliar with double back horns like the Victor, but could never understand why a design like this would be better than a single, longer horn path. I could see some db gains in the mid bass, but if were going big, why not go for extension instead?
#3. I've built your frugal horns, so just want to say thanks Dave for all you have done in the DIY community.
As far as i recall, yes.
The bifurcaed horn allows for better packaging. Not a new concept... take the Klipshorn or the big Tannoys for instance.
😀
dave
I dunno about Victor vs. BiB, but as an acoustics guy I would say that the A/B/C area in your diagram would be better with some kerfed rounded sections. Pressure waves prefer smooth expansion, not all those right angle corners. Even some kind of rounding at the intersection of the green lines.
I also noticed the driver height is incorrect; it must be aligned with the belly button for proper resonance. 😉
The design looks so simple, I'm surprised I don't feel I've seen it before. Maybe you could put lights and a smoke machine down inside 😱
I also noticed the driver height is incorrect; it must be aligned with the belly button for proper resonance. 😉
The design looks so simple, I'm surprised I don't feel I've seen it before. Maybe you could put lights and a smoke machine down inside 😱
BIB is dead simple and a fairly crude tapped horn so even with proper corner loading has a fair amount of ripple. Victor has a much larger mouth and all the bends help keep higher frequencies from getting to the mouth so it will be smoother and less sensitive to room placement.
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I'd also guess that the BIB dwarfs Victor size-wise
This is not a good idea. The expansion at the fold creates an acoustic low pass on the mouth radiation reducing the ripple.
One smooths the corners to extend the mouth's response upwards and is, in general, not a good idea in any BLH.
dave
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I'd also guess that the BIB dwarfs Victor size-wise
This is not a good idea. The expansion at the fold creates an acoustic low pass on the mouth radiation reducing the ripple.
One smooths the corners to extend the mouth's response upwards and is, in general, not a good idea in any BLH.
dave
Smooth expansion promotes maximum efficiency across the full bandwidth of the horn. As Dave says, whether you actually want that is another question entirely. At low frequencies, wavelengths are too long to be bothered; sharp bends / angles tend to have more impact at higher frequencies, as wavelengths drop. This can be profitably employed, since in a back-load you really need to have your acoustic low-pass in place by ~250Hz - 300Hz to prevent too much unwanted midband passing through the horn. The BIB style tapped conical horn is typically damped from the throat to just below the driver, & with a layer on the bottom, which further helps attenuate the unwanted midband frequencies / harmonics. If you want maximum LF extension and are willing to sacrifice some refinement to get it, it's a good way to do it. Best corner loaded.
Re the Fostex plan that comes with the drivers, whatever it's other merits, 21Hz is a trifle ambitious; the measurements indicate that is about 24dB down. Realistically I'd expect useable output to about 40Hz, but not much lower.
Re the Fostex plan that comes with the drivers, whatever it's other merits, 21Hz is a trifle ambitious; the measurements indicate that is about 24dB down. Realistically I'd expect useable output to about 40Hz, but not much lower.
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The flare of the horn is 21 Hz. But it is not more of a 21 Hz horn than a 2 meter long un tapered pipe is a "0 Hz horn". It is a tapered quarer wave pipe, at 2.15m an untapered pipe would resonate at 40Hz a slight positive taper will reduce the Q of the resonance and increase the frequency. The impedance has a dip at 45 Hz the tuning frequency of the pipe.
I hadn't read the text earlier so I was wondering where the 21Hz had come from. Big truncation since as you say, axial length is nowhere near sufficient for that.
I think Dave's comment re T/S was based on the initial time the 163 was released, since the parameters are now up. A theoretical horn loaded BW of 6.75Hz - 464.73Hz is available assuming a voltage source; more practically speaking, I wouldn't be inclined to tune < 39.5Hz in a modest sized box, or <28Hz in a large horn with a decently sharp acoustic XO slope.
I think Dave's comment re T/S was based on the initial time the 163 was released, since the parameters are now up. A theoretical horn loaded BW of 6.75Hz - 464.73Hz is available assuming a voltage source; more practically speaking, I wouldn't be inclined to tune < 39.5Hz in a modest sized box, or <28Hz in a large horn with a decently sharp acoustic XO slope.
Thank you for your input.
I will have to do more research on whether the Fostex plan is a good choice.
This is a very powerful, highly dampened driver, so I question how well it will work in other enclosures. From the curves I've plotted in WinISD and Hornresp, it's behaves very differently compared to other Fostex Drivers like the Sigmas.
Is this quote from from the Fostex Plans specific to the FE163En-S when compared to other Fostex horns, or is this standard "Fostex Lingo"?
"A back loaded horn type enclosure which fully maximizes the FE163En-S's over-damping characteristic has been designed. In order to flatten the low frequency response and to realize a massive but yet speedy low frequency reproduction, the horn opening was brought closer to the speaker unit (CW horn composition, fc = 21 Hz, horn length: 215 cm)."
Also, I see the 21hz is there on the graph, but way down at 70dB. Would this be brought back up by room loading and/or corner placement?
I will have to do more research on whether the Fostex plan is a good choice.
This is a very powerful, highly dampened driver, so I question how well it will work in other enclosures. From the curves I've plotted in WinISD and Hornresp, it's behaves very differently compared to other Fostex Drivers like the Sigmas.
Is this quote from from the Fostex Plans specific to the FE163En-S when compared to other Fostex horns, or is this standard "Fostex Lingo"?
"A back loaded horn type enclosure which fully maximizes the FE163En-S's over-damping characteristic has been designed. In order to flatten the low frequency response and to realize a massive but yet speedy low frequency reproduction, the horn opening was brought closer to the speaker unit (CW horn composition, fc = 21 Hz, horn length: 215 cm)."
Also, I see the 21hz is there on the graph, but way down at 70dB. Would this be brought back up by room loading and/or corner placement?
Set aside any hope of a useable 21Hz from a 6 1/2in wideband drive unit. It's not going to happen. Not with decent performance anyway. Room lift may (may) give you a bit more, depending on location, dimensions, construction & furnishings etc. But that's a trifle over-ambitious. In general, a useable 40Hz or so is a realistic target to have, with anything lower being a bonus, & in general it's not advisable to push them extremely hard -they won't thank you for it. Modest sized widebanders like the unit in question can do many things well, but sub-bass with any semblance of dynamic range isn't really their forte. As noted, a BIB is one of the better compromises if LF extension is what you're after & you don't mind sacrificing a bit elsewhere -assuming they're corner-loaded they're solid performers & certainly do LF well. If you want to use the standard tuning, you should have solid output to the low 30Hz regions. You can tune lower, but I wouldn't advise it.
Regarding the comments, that's fairly standard Fostex. The 163 is certainly a highly damped unit, but its Q is not unusually low by Fostex standards. The old FE166E had a Qt of 0.21 for example, and the current FE166En is about 0.25, placing the 163En-S smack in the middle. For the sake of interest, the lowest Q driver I can recall Fostex producing was the defunct FF225K, which had a Q of 0.16 The enclosure appears to be a variation on the typology employed for the ESigma range. They're OK; Fostex boxes vary from poor to reasonable, but from a quick eyeball, I'd expect this to be one of their better examples. You'll probably get better results from a larger cabinet. Depending on where your priorities lie, something like a BIB, or a design of similar bulk but slightly higher tuning, with a less compromised expansion.
As is, it's not an idea candidate for a typical vented box inasmuch as while you can certainly do it, you certainly won't get much LF gain & will probably need a shelving filter for the top end to fix baffle-step. With that said, a point to keep in mind is that traditionally, Fostex design drivers & boxes they will be used with a high output impedance amplifier, and sometimes small Japanese rooms. So that ideally should be factored in (it should be factored in anyway if that's the sort of amp they'll be employed with).
Regarding the comments, that's fairly standard Fostex. The 163 is certainly a highly damped unit, but its Q is not unusually low by Fostex standards. The old FE166E had a Qt of 0.21 for example, and the current FE166En is about 0.25, placing the 163En-S smack in the middle. For the sake of interest, the lowest Q driver I can recall Fostex producing was the defunct FF225K, which had a Q of 0.16 The enclosure appears to be a variation on the typology employed for the ESigma range. They're OK; Fostex boxes vary from poor to reasonable, but from a quick eyeball, I'd expect this to be one of their better examples. You'll probably get better results from a larger cabinet. Depending on where your priorities lie, something like a BIB, or a design of similar bulk but slightly higher tuning, with a less compromised expansion.
As is, it's not an idea candidate for a typical vented box inasmuch as while you can certainly do it, you certainly won't get much LF gain & will probably need a shelving filter for the top end to fix baffle-step. With that said, a point to keep in mind is that traditionally, Fostex design drivers & boxes they will be used with a high output impedance amplifier, and sometimes small Japanese rooms. So that ideally should be factored in (it should be factored in anyway if that's the sort of amp they'll be employed with).
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This is a WinISD chart comparing and existing enclosure I have of 53L Bass reflex:
-FE168ez Sigma (40hz Peak)
-FE163En-S (60hz Peak) (not good at all for Bass Reflex)
-FE168ez Sigma (40hz Peak)
-FE163En-S (60hz Peak) (not good at all for Bass Reflex)
An externally hosted image should be here but it was not working when we last tested it.
Not in that volume. That's substantially over-sized / mistuned for those units in a stock reflex type box
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This is the BIB calculation. Not bad. It fits within a 5'x5' Baltic Birch being 60" tall.
-Is there a way to figure out the extension or tuning freq? Also, can the design be adjusted for a 40hz tuning freq?
-Is there a way to figure out the extension or tuning freq? Also, can the design be adjusted for a 40hz tuning freq?
An externally hosted image should be here but it was not working when we last tested it.
It's tuned to 1/2 wave Fs, which should give useable output in practice to the mid-low 30Hz regions. Which is bloody good for a 6 1/2in wideband driver with a fairly high Fs. You could tune a bit lower, which is a function of axial length (i.e. it will have to be longer), but go easy. A 70in tall box, for a near-140in expansion length for e.g. will give you 1/2 wave at 48.24Hz & will be good for a fairly solid 30Hz. I wouldn't push this driver lower. It's not a subwoofer.
For starters, with the FE163En-S I would suggest you start looking at the D-168 (IIRC thats the model), D37 or the Nessie Jr. These are all Japanese designs.
You seem to be concerned about bass, go with the D-168 which is the middle sized "Swan type" speaker. I built a pair and used the FE166es-r and had too much bass despite many attempts to tune them. Had to pull them way into the room to control it. Of course the room dominates, in my case with the exception of the roof it is all concrete.
You would need to do some tuning but that is part of the experience.
The D-37 I think would be the sweet spot, never built them but they are the "Grand Father" of Mr. Nagaoka's designs and a perennial favorite for ~6 inch back loaded horns.
The Nessie Jr is intended as an AV speaker but that does not discount it.
Dave (Planet 10) mentioned the Victor which is a design by Scottmoose. I remember awhile back he tried it with the FE166es-r and was quite impressed so that is another option.
Have a look here
for the Japanese designs.
http://homepage3.nifty.com/spida/pag9-01-16.htm
Good Luck
Andrew
You seem to be concerned about bass, go with the D-168 which is the middle sized "Swan type" speaker. I built a pair and used the FE166es-r and had too much bass despite many attempts to tune them. Had to pull them way into the room to control it. Of course the room dominates, in my case with the exception of the roof it is all concrete.
You would need to do some tuning but that is part of the experience.
The D-37 I think would be the sweet spot, never built them but they are the "Grand Father" of Mr. Nagaoka's designs and a perennial favorite for ~6 inch back loaded horns.
The Nessie Jr is intended as an AV speaker but that does not discount it.
Dave (Planet 10) mentioned the Victor which is a design by Scottmoose. I remember awhile back he tried it with the FE166es-r and was quite impressed so that is another option.
Have a look here
for the Japanese designs.
http://homepage3.nifty.com/spida/pag9-01-16.htm
Good Luck
Andrew
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Okay thanks ScottMoose. I would be happy with a solid 40hz. Good to know it works well in a BIB.
Here is the Hornresp Plots of the Fostex provided FE163eN-S horn plans. I spent forever getting the values correct, and I'm still not sure I have everything 100%? One thing uncertain is the flare rate, I estimated for S2 area and distance, which I think dictates flare. I'm not an expert, and still need to research it more.
Here is the Hornresp Plots of the Fostex provided FE163eN-S horn plans. I spent forever getting the values correct, and I'm still not sure I have everything 100%? One thing uncertain is the flare rate, I estimated for S2 area and distance, which I think dictates flare. I'm not an expert, and still need to research it more.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Those are quite ugly curves... the kind that give reflex boxes a bad rap.
dave
For the sake of interest, FE163En-S in the Factory plan provided, & the Nagaoka D37. I've held these as 1/2 space, without adding any damping for consistency.
Out of curiosity (since I hadn't tried before), I took a look at the FE163En-S in Victor; doesn't look too bad. Note that the conditions of the sim. however are not the same as the others; the cabinet here is damped as designed & assumes the sort of boundary loading the box was intended for, so this is purely FWIW / for academic interest -it's not a valid comparative baseline given the difference in variables.
Edit -voltage source assumed in all cases.
Out of curiosity (since I hadn't tried before), I took a look at the FE163En-S in Victor; doesn't look too bad. Note that the conditions of the sim. however are not the same as the others; the cabinet here is damped as designed & assumes the sort of boundary loading the box was intended for, so this is purely FWIW / for academic interest -it's not a valid comparative baseline given the difference in variables.
Edit -voltage source assumed in all cases.
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