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It seems these drivers are still being made and sold, they have been around a looong time. Heck, I remember Dave D said they were his favourite back in 2005….
But are they still a thing? Nobody seems to post on these drivers much anymore. Are they about to go extinct?
Would they not make good options for a FAST (mid-tweet in a two-way) given their 90dB sensitivity ?
But are they still a thing? Nobody seems to post on these drivers much anymore. Are they about to go extinct?
Would they not make good options for a FAST (mid-tweet in a two-way) given their 90dB sensitivity ?
Yes.🙂 They were never cheap drivers to buy, so maybe that's one reason why they aren't more popular.
jeff
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The FE108e∑ has stood the test of time. Dates from the late 90s. A lovely driver. Beautifully made.
Has a really seductive midrange, top is what i would call vintage. Much smoother than most Fostex right out of the box (does benefits from a coat of puzzlekoat).
You have to work to have them make any bass, not bad with FH3 and corners, but shines best in Aiko.
Would make a very nice midTweeter.
The lowest they could be practically taken is 180Hz, a stuffed 1.1 litre sealed box which gives a built in 2nd order roll-off.
I’d double that and add a HP. But depends on how loud you want to go.
dave
Has a really seductive midrange, top is what i would call vintage. Much smoother than most Fostex right out of the box (does benefits from a coat of puzzlekoat).
You have to work to have them make any bass, not bad with FH3 and corners, but shines best in Aiko.
Would make a very nice midTweeter.
The lowest they could be practically taken is 180Hz, a stuffed 1.1 litre sealed box which gives a built in 2nd order roll-off.
I’d double that and add a HP. But depends on how loud you want to go.
dave
The metronome is one of those enclosures that make you wonder where is all that bass coming from.
You can step up and choose FE168e∑. This is the driver I use personally. Mr. Pass seconded this as a cheaper option compared to expensive fullrange offerings.
Yes, still made and there do not appear to be any signs of replacement.
Yes, should be fine for that.
Fully agree. Actually, I wanted to post my experiments a little later but it is too tempting, to find out what you guys think.... These speakers are not finalized yet, I want to make them fully active, so far running with external power amp while that project is ongoing.
See the picture attached. This essentially is a IKEA CD tower cut in half, with little compartments on the top for the FE108Sigma, volume ~2liters since that was natural given the position of the little holes for the shelves 😀
I did add an air motion transformer as supertweeter, but undecided as of yet whether I want it or not. The "original" highs of the Fostex I don't like too much, want to add a little sparkle. And for the bass, I bought 4 very cheap woofers per side (€4 each) and will add motion control to them. Crossover frequency for the whole thing is 200Hz.
So, the FE108 is doing pretty much all the hard work, I did put a shelving filter though since the upper mids are really too strong, with the filter kicking in at 3kHz, with 6dB damping. They only came alive after 50hrs or so of burn-in, lots of detail and all the precise imaging you could want. Sweet, if you ask me.....
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this looks very interesting, I'd like to hear more about your experience when you have listened to this.
I have a commercial floorstanding two way speaker and I could be tempted to rip out the metal dome tweeters and put in the Fostex and a new cross-over. My speaker was very expensive, a PMC, but it's value today is limited given it's age (20 yrs) and the tweeters have to be upgraded anyhow.
In this way, it becomes an interesting choice for me,
Either: replace the tweeters for modern units and retain a 2-way with XO around 2.5kHz
Or: turn it into a FAST where the XO could be low-order but I don't know where to put it other than it should not be too low or the Fostex will run out of excursion and a passive XO will also get too challenging.
I suspect Dave (p10) could suggest an XO based on centre-to-centre spacing of the Fostex vs the 6" mid-woofer ?
jeff - they aren't cheap but these days I find my time is too often undervalued and I'd be better to buy the best rather than futz around!
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They may only list a small Xmax but I've run these full range in a small venue and turning them up could make it difficult for people to talk.
There are good reasons for considering the FAST, but there's no need to cut too heavily into the midrange.
There are good reasons for considering the FAST, but there's no need to cut too heavily into the midrange.
The standard recipe i use for turning 2 (or more) way speakers into WAWs is to run a 4” PVC pipe from behind the midTweter out the back of the box.
4” will not be bigg enuff for the FE108, 5 or 6” would be more appropriate.
dave
4” will not be bigg enuff for the FE108, 5 or 6” would be more appropriate.
dave
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in my case, the PMC cabinet is a 'done deal' and I don't want to create a big pipe sticking out the back so I may find this is not the best option compared with a simple tweeter upgrade. I could possibly squeeze a pyramidal cover over the back of the driver to enclose it and separate it from the main transmission line that the mid-woofer lives inside.
Edit: actually, looking at the cut-out drawing a pipe to the back is feasible. It would be irreversible butchery though.
Edit: actually, looking at the cut-out drawing a pipe to the back is feasible. It would be irreversible butchery though.
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I like midTLs, but in your case a trip down to the dollar store and pick out a suitable size bowl to use as a sealed box. somewhere between 1.5-2 litres.
Should be small enuff to be insignificant to the fold in the line.
dave
Should be small enuff to be insignificant to the fold in the line.
dave
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I found a formula somewhere on this forum that the baffle step F3 = 115 / width (m). For my speaker width = 0.2m so F3 = 115/0.2 = 575 Hz
I should measure the response of my mid woofer. I bought one of those calibrated USB microphones that everyone likes at least a year ago and never took it out of the box. I don't know how to use it but they can't be that hard to get the hang of.
Cost is not an issue, priority is quality of results and not making a botch up out of my lovely PMCs.
WRT to BS.
Ideally, if one is using this metric, XO should be 0.707x <BS(-3)< 1x. I tend towards the bottom of the range. Given the close pacement of the twetere to the midbass there should be little issue getting to less than quarter wavelength centre-to-centre.
dave
Ideally, if one is using this metric, XO should be 0.707x <BS(-3)< 1x. I tend towards the bottom of the range. Given the close pacement of the twetere to the midbass there should be little issue getting to less than quarter wavelength centre-to-centre.
dave
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If the c to c spacing was 6", or 0.15m, it would be a quarter wavelength at 550Hz which matches up rather nicely with the BS number.
And if the F-M curve were another metric we'd want to be < 1KHz so we're good on that front too.
It's still in the telephone band but far below the critical part of it.
And if the F-M curve were another metric we'd want to be < 1KHz so we're good on that front too.
It's still in the telephone band but far below the critical part of it.
