I have a pair of Fostex Fe126En drivers in boxes I made to the OEM spec. Sadly one of the drivers has failed and my children have damaged the other one. I wax looking for replacement drivers but saw that the Fe126En has been superseded by the 126NV. Is it a true drop-in replacement that would sound at least as good in a box designed for the 126En or just a newer model in that size category, requiring a different box? (I can still obtain NOS 126Ens so just wondering whether to stick with those or if there's any benefit putting the 126NVs in the existing boxes. I don't have the time to build a new pair of boxes at the moment...)
None of those are a good start. I haven’t simmed the new driver for a reflex, if you built the 10 litre factory reflex, given what Scott told me in summary (the new one fits all the standard FE126 horns), might well be happier with the FE126nv.
If that is the box you built i can sim it (later) and suggest vent changes to optimize performance.
I have nothing good to say about the so called “horn/hybrid” box.
dave
If you read the link i posted to my blog you will see that i do not think the factory FE126 reflex box is a very good design.
The sims suggest that the new driver will perform as poorly as the FE126En in that reflex box. It is worth noting that the facroty box nandpe shows has a 115mm vent, the drawing i have is 102mm. The longer vent mmakes things worse.
The ideal Fonken for an FE126nv is 4 litres, the new driver 5 litres. One could install a brick (or other solid volume fill) and retune the box.
This driver really want to be in a horn (it is noteworthy that the recommended horn is no longer the reflex/horn (so called) hybrid suggested for the earlier driver.
Frugel-Horn Mk3, Austin 126, Valiant. Probably work OK in BK12m, but that a step down.
dave
The sims suggest that the new driver will perform as poorly as the FE126En in that reflex box. It is worth noting that the facroty box nandpe shows has a 115mm vent, the drawing i have is 102mm. The longer vent mmakes things worse.
The ideal Fonken for an FE126nv is 4 litres, the new driver 5 litres. One could install a brick (or other solid volume fill) and retune the box.
This driver really want to be in a horn (it is noteworthy that the recommended horn is no longer the reflex/horn (so called) hybrid suggested for the earlier driver.
Frugel-Horn Mk3, Austin 126, Valiant. Probably work OK in BK12m, but that a step down.
dave
Thanks planet10. I liked the idea of horns for speakers like that anyway, the old drivers are in the old OEM hybrid horn / reflex setup so I'll probably start the replacements off in that with the reflex port plugged and then make a proper, more suitable horn for them when time allows.
We burned our build. More bass can actually be had form the 4 litre mFonken.
Do note that Stefan in Kent had FH3 flat-paks if that helps.
dave
Dave, Stefan's website says he is in Warwickshire rather than Kent (although by Canadian standards I'm sure that looks just next door...)
I was told Kent, looks like part of greater London to me. You could fit many UK’s into British Columbia, our sense of distance is quite different.
dave
dave
Southam; definitely Warwickshire. About 15 miles south east of Birmingham and roughly 9 south of Coventry. Kent is to the SE of London, about 80 - 90 miles away as the crow flies; call it in practical terms about 100 by road.
Either way -the Fostex 126 (it was designed for the 2-generation-old FE126E model) hybrid small horn does burn well. 😉
The NV series in interesting as it marks a bit of a departure for Fostex, at least as far as published spec. is concerned for the 126 & larger units; Q has increased somewhat compared to their predecessors. Presumably they're thinking more of solid-state amplifiers; the old E and En series were in part geared up to SET and equivalent higher output impedance designs.
Either way -the Fostex 126 (it was designed for the 2-generation-old FE126E model) hybrid small horn does burn well. 😉
The NV series in interesting as it marks a bit of a departure for Fostex, at least as far as published spec. is concerned for the 126 & larger units; Q has increased somewhat compared to their predecessors. Presumably they're thinking more of solid-state amplifiers; the old E and En series were in part geared up to SET and equivalent higher output impedance designs.
I would like to ask for help. Should be put polyesterwatte or damping in the modified Hybrid BH box?
Dear venezia101,
Please put a small amount of sound absorbing material in the back chamber, as the duct at mouth acts as a damper.
Please put a small amount of sound absorbing material in the back chamber, as the duct at mouth acts as a damper.
Dear Nandappe,
Excuse me for disturbing. I built the speaker, but I feel the treble is a bit high. Unfortunately, I can't measure without an instrument. Can you recommend a crossover to improve your sound image?
Best regards, venezia101
Excuse me for disturbing. I built the speaker, but I feel the treble is a bit high. Unfortunately, I can't measure without an instrument. Can you recommend a crossover to improve your sound image?
Best regards, venezia101
Dear venezia101,
What crossover is it?
FOSTEX FE series has a high rise, so it would be better to add more sound-absorbing material, or use a filter to reduce the treble, or change the driver to 125WK.
Sorry, I haven't tried filters, so I don't know much about them.
What crossover is it?
FOSTEX FE series has a high rise, so it would be better to add more sound-absorbing material, or use a filter to reduce the treble, or change the driver to 125WK.
Sorry, I haven't tried filters, so I don't know much about them.
How exactly will sound absorbing material behind the driver remedy the issue with its rising top end?
(spoiler alert; I think I know the answer to that)
(spoiler alert; I think I know the answer to that)
Notwithstanding my experience with the specific Fostex enclosure depicted above - originally designed decades ago now for a much different driver - I think the key word in my post would be behind the driver?
Wouldn’t any acoustic treatment intended to mitigate issues with sound projected into the listening space need to be applied to the external surface of the enclosure, or in this case, the diaphragm itself? Such tweaking of cone materials happens to be something that has been discussed for years at great length by several members here, but is a very delicate procedure, fraught with opportunities for irreversible error. I’ve heard and owned several Fostex treated thusly, and it certainly helps.
That said, while not yet having heard the latest version of the 126, I’d concur that the FF series have smoother mid to highs, and definitely more extended low frequencies without the need for the gain below the driver’s “mass corner” that a well designed enclosure can provide - at the price of sensitivity. Then again, any active or passive EQ sufficient tame a broad rising response- as opposed to narrow band resonances - would likely reduce the system’s net output, so there’s that.
Wouldn’t any acoustic treatment intended to mitigate issues with sound projected into the listening space need to be applied to the external surface of the enclosure, or in this case, the diaphragm itself? Such tweaking of cone materials happens to be something that has been discussed for years at great length by several members here, but is a very delicate procedure, fraught with opportunities for irreversible error. I’ve heard and owned several Fostex treated thusly, and it certainly helps.
That said, while not yet having heard the latest version of the 126, I’d concur that the FF series have smoother mid to highs, and definitely more extended low frequencies without the need for the gain below the driver’s “mass corner” that a well designed enclosure can provide - at the price of sensitivity. Then again, any active or passive EQ sufficient tame a broad rising response- as opposed to narrow band resonances - would likely reduce the system’s net output, so there’s that.
Concur. Almost all upper midrange & HF output from drivers of this type are emmitted from the front of the cone and the dustcap, especially if the latter is direct-coupled to the end of the coil. Relatively little comes from the back of the driver, and much of what is produced is dispersed by the motor structure & rear suspension. Ergo adding damping behind the drive unit will not significantly affect higher frequencies, other than damping early reflections, which requires relatively little.
One exception is if you add sufficient amounts of damping in close proximity to the driver that it acts more like a solid and the air-compression mass-loads the cone & suspension, potentially warping the cone under high loads & affecting its TL modes (which is what produces a large amount of its midrange & HF). A related issue is when the driver is mounted in very close proximity to cabinet walls -similar situations can sometimes occur, plus it is difficult to damp early reflections in such conditions.
One exception is if you add sufficient amounts of damping in close proximity to the driver that it acts more like a solid and the air-compression mass-loads the cone & suspension, potentially warping the cone under high loads & affecting its TL modes (which is what produces a large amount of its midrange & HF). A related issue is when the driver is mounted in very close proximity to cabinet walls -similar situations can sometimes occur, plus it is difficult to damp early reflections in such conditions.