FE83En options? - DBR, Onken, TL ?

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With the rationalization of the Fostex line, those who like the sound of these paper cone high sensitivity drivers have fewer choices. At the small end, the only 3" driver available easily today is the FE83En. What can we make with it ?

With small drivers I think of small speakers, Planet10's uFonken based around the FF85k was is a great example. But what of the FE83En, it seems unsuitable for that enclosure, being better suited for a relatively big full-size horn. What else can we do with it ? Scottmoose suggested looking at some alternatives.

1) Foxtex recommends a Double BR box. I've tried modeling this using an on-line calculator at Lautsprecher Gehäuseberechnung mit Thiele Small Parameter. The results show a surprising amount of bass extension (7dB down at 60Hz), but the DBR typically produces a dip in the response (see attached FR plot, red line). OK, the FR looks ugly, but the reality may not be as ugly as the simulation and some who have built this say they are pleased with the results. Other options include the double chambered design of Weems/Augspurger but with 3 ports in total it's all getting a bit complicated.

2) I've also considered an Onken design, following the lead of the uFonken. This means aligning the box for extended bass shelf (EBS) by using a larger enclosure. I made some progress modeling this (see attached FR plot, redline); 5dB down at 70Hz. This model is based on a Vb of 4 litres. The total port area is 25sq.cm which is good because it's within the recommended (by some) range for an Onken of 85% to 100% of Sd. This pushes port length to the range of 25 to 35 cm which is also recommended (by some) for an Onken .

With a high Qts driver any kind of sealed/vented box solution is going to have some rising bass response, but I figure this will be handy in the fight against baffle step losses. Perhaps this peakiness from the FE83En may be just the ticket.

3) Next up - maybe a folded tapered TL, like some of those shown here: http://www.diyaudio.com/forums/full...p-tl-proposals-everything-under-one-roof.html



  • Fostex FE83En DBR.png
    Fostex FE83En DBR.png
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  • FE83_Vb4_5d8cm25.png
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I can't come up with an alignment i'd use for a miniOnken (i'd never base one on your sim). Close as i could get generates a model with a +4 dB shelf from ~130-200 Hz, F3 of 100. Starts exceeding xMax at ~1/3 w below 200 Hz

Best non-exotic bet for this is 5 litre sealed, F3 170 Hz, F10 95 Hz.

This thing is really a mid-tweeter (as one would expect from Fs = 165 Hz).

Yes, I had a read of one of the threads on the A6 from Mark. I also liked what I saw, particularly the use of a paper cone because for whatever reason I come across people with strong opinions in favour of paper (will this version come to Canada ?). I still wish it were 8 Ohm but I guess we can't have everything.

Anyhow, it doesn't look as if the FE83 is worth any more effort for now.

The FF85k really fills a nice spot, I just can't understand what Fostex were thinking when they killed this one. But with two kids I don't want to use a driver I can't replace !
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