I would use a higher rated resistor. If you can't get higher rated resistors, parallel a couple of the 5w to give the target value with increased power handling.
DCR of the inductor would normally be a bit high; I don't know what your amplifier is, but if its a conventional solid state or PP valves, the extra series resistance will likely be useful, so should be fine.
DCR of the inductor would normally be a bit high; I don't know what your amplifier is, but if its a conventional solid state or PP valves, the extra series resistance will likely be useful, so should be fine.
Hi all,
Let me present my Half Changs Fostex FE206En, finally completed yesterday.
Initially built with an exotic plywood, which didn’t look well, so I covered them by oak veener and finished with hardwax.
Now playing with 3.6R resistor, but going to add an 1mH inductor to smoothen mids and hights.
I have read whole the thread looking for the mods and I found a few.
Could you guys please share your thoughts which mods are most impacting the sound, best to start with them?
Let me present my Half Changs Fostex FE206En, finally completed yesterday.
Initially built with an exotic plywood, which didn’t look well, so I covered them by oak veener and finished with hardwax.
Now playing with 3.6R resistor, but going to add an 1mH inductor to smoothen mids and hights.
I have read whole the thread looking for the mods and I found a few.
Could you guys please share your thoughts which mods are most impacting the sound, best to start with them?
Attachments
@gallileo1982,
Besides proper lining of the cabinet, you really need Baffle Step Correction. BSC makes a huge difference in the sound for a HC w/ FE206 driver. Notes from my build in 2008 using the FE206e:
--Baffle step circuit (BSC) consists of 1 mH inductor in parallel with 5 ohm, 12 watt Mills resistor on the positive lead of the driver.
I would not have tried this build with the FE206e instead of the FE207 which Scott designed the HC for, except that I listened to Bob Trancho's Build with the FE206e and found it very enjoyable.
Cheers, Jim
Besides proper lining of the cabinet, you really need Baffle Step Correction. BSC makes a huge difference in the sound for a HC w/ FE206 driver. Notes from my build in 2008 using the FE206e:
--Baffle step circuit (BSC) consists of 1 mH inductor in parallel with 5 ohm, 12 watt Mills resistor on the positive lead of the driver.
I would not have tried this build with the FE206e instead of the FE207 which Scott designed the HC for, except that I listened to Bob Trancho's Build with the FE206e and found it very enjoyable.
Cheers, Jim
Thanks Jim.
That’s what I’m going to do - add the inductor.
Did you try by the chance phase plugs?
Cheers
That’s what I’m going to do - add the inductor.
Did you try by the chance phase plugs?
Cheers
No, never tried phase plugs. Could never bring myself to cut into the cone/dust cap. I did use the 'bearded' whizzer tweek on a pair of FE167e drivers though. Just a little fiber fluff between the whizzer and the main cone toned down a small resonance that bothered me.
Cheers, Jim
Cheers, Jim
I have the same concern as to cutting out the dust cup.
Could you post a picture of the whizzer tweak?
Also, what the wire gauge inductor have you used in the BSC?
Could you post a picture of the whizzer tweak?
Also, what the wire gauge inductor have you used in the BSC?
Here is a photo of the FE167e with Parts Express AcoustaStuf fiber damping around the whizzer; it is well teased out, and nothing extra to hold it in, so it needs to be gently pushed back into place from time to time.
As far as I can remember, the 1.0 mH air core indictors were 18 gauge.
Cheers, Jim
As far as I can remember, the 1.0 mH air core indictors were 18 gauge.
Cheers, Jim
Attachments
Hi Jim,
thanks for the picture.
I'm going to try with a window foam stripe seal, should do the same job.
Also awaiting the parcel with inductor, very curious how will it impact the sound.
Cheers!
thanks for the picture.
I'm going to try with a window foam stripe seal, should do the same job.
Also awaiting the parcel with inductor, very curious how will it impact the sound.
Cheers!
My experience with Fostex back loaded horn design are quite versatile. Fostex 8 inch drivers can be mixed with god results.
(I have heard 203En-S / 208EZ / 208Es-R and therefore think the 206/207 models is the same «family»)
(I have heard 203En-S / 208EZ / 208Es-R and therefore think the 206/207 models is the same «family»)
They aren't a Fostex design -they're one of mine, so a few different conditions are in play.
That said, althoigh I don't know of anybody who's run the NV2 in that enclosure, the current generation units are certainly much closer to the old FExx7E series it was designed for, so as far as the LF loading is concerned up to the mass-corner they should be quite similar, with the main differences probably lying further up the range: Fostex have also changed their measurement methods & presentation, so they're not exactly comparable. Certainly worth a shot, I'd say. It won't be identical, but in the right ball-park.
That said, althoigh I don't know of anybody who's run the NV2 in that enclosure, the current generation units are certainly much closer to the old FExx7E series it was designed for, so as far as the LF loading is concerned up to the mass-corner they should be quite similar, with the main differences probably lying further up the range: Fostex have also changed their measurement methods & presentation, so they're not exactly comparable. Certainly worth a shot, I'd say. It won't be identical, but in the right ball-park.
Good to hear🙂
I will mount them tomorrow. After few days i will tell you what my ears will be telling me.
Thanks Scott
Cheers.
I will mount them tomorrow. After few days i will tell you what my ears will be telling me.
Thanks Scott
Cheers.
I too am interested in a replacement driver for the half chang. My Pioneer B20s have developed a few small tears in the surrounds and my toddler loves to poke the dust caps. Glad to hear that the current Fostex offerings are likely to be near "drop in" replacements. I wonder if the addition of a series resistor would help like on the older 206 variants?
206NV2 already has a rated Qt identical to the old FE207E the box was nominally designed for, so it may not do much in that sense, although it might be of use in other ways. As GM often points out, & per the trad. method, a variable resistor in series which you can adjust to help ~mimic the variable output impedance amplifiers we've spent decades missing (know it or not 😉 ) can be a useful way of tuning the system since, modest SPL loss aside, it does affect the rest of the range as these drivers are frequency-varying loads.
Fostex Fe207E works with bass reflex, little higher Qts. While most Fostex drivers have lower Qts and more suitable for backloaded horn.
That used to be the case, at least in part, but it's less so now. Up to the En series, the FExx6 units & their predecessors were relatively low Q, as were (most of) the FExx8ESigmas etc. The same went for the FFxx5K series too. There was always some variation there though, with some exceptions in the E / En series for the smallest models, while the long-gone Fxx0a and FXxx0 series had middling Q values. Things started to change a bit more widely when the FFxx5k series was replaced by the FFxx5wk, and more recently the FExx6NV and current NV2 have seen average Q values rise. The motors are still underhung short-throw designs, so they still benefit from relatively high efficiency loads, but they're a little less specialist these days than they were.
I think NV2 is pretty good replacement for older FE versions. I had few full rangers before and still have 208 sigma , FE126nv2 and SB Acoustics that i want house as well. Two low watts amps i have didn't worked well. It's just like you would connect solid state amp to Fostex206En, maybe not to same extend but that's what i thought (My friend use to have 206en in factory horn). Two vintage Sansui receivers 771 and 331 didn't do the job either. Rotel A10 was in last spot. But little handmade Push-pull Tranzistor amp with only 4watts into 8ohms work really well, maybe a little bit hot on the top but it has lots of bass and its really transparent. Mind you I'm 60 years old so my hearing it's not top notch anymore🙂. I forgot that little cheap D-amp did well as well. In my opinion law watts tube amps won't work as good as with En version driver. Not all amplification work with all speakers. Now i have question to Scott, can you design mini Chang for Fe126nv2? 🙂.
