Fostex FE167E as midrange driver

Has anyone here used the Fostex FE167E as a midrange driver? I'm thinking of using it as a midrange driver in a sealed box (with baffle step correction) crossed over to a powered subwoofer at 100-150 Hz and augmented at the top end with a suitable tweeter. Since a tweeter would be used at the top and the Fostex would be reasonably inexpensive, I might consider removing the whizzer on the 167.

Dean
 
I have a similar scenario. I want to build a pair of three driver open baffle speakers (ie cheap Orions), and I was looking at the Fostex 167 for mids/highs and an Ascendant Atlas 12" from 100-120hz down, augmented with a good quality tweeter (FT207D maybe) from 10k up. So you think a Fostex is overkill? I was considering the 207 because it goes a bit lower than the 167, but it gets peaky above 5k. The 167 is much smoother up to 10k.

What else would you recommend in the 167's place? The 103 drops off too quickly below 200hz and the RS 40-1197 frequency response doesn't look quite as good as the 167's.

And any suggestions for quality tweeters are welcome. There are just too many to pick from for me to sort through them all. I'd considered Morel or Vifa but none of them look very good. Seas and Scanspeak on the other hand, are too rich for my blood. I take that back, the Scanspeak D2010/8513 looks pretty good but not quite as good as the FT207D. I was looking for something in the ~$50 range. I didn't really want to spend more on tweeters than my mid range.
 
Greets!

Why? It and the other small drivers suggested have too limited a dynamic headroom for any app other than severely compressed signals (OTA TV or radio broadcasts, etc.) or in a MUZAK (background, intimate, etc.) app.

In today's digital world an audio system needs to be able to reproduce up to +30dB transient peaks in the 250-500Hz BW without clipping the amp or exceeding the driver's ~linear limits (Xmax), so with 100dB max peak capability it's limited to 70dB average playback. Even the highly compressed HT reference level requires 105dB peaks/listening position/channel, so forget most (all?) small drivers for any serious music listening/HT if not horn loaded or in multiple driver arrays.

Really, a 6.5" is too small for the intended app, and even an 8" is marginal at best, so why the better designs use two in MTM layouts and XO them when they get ~ 1 WL apart. One of the great losses in today's scaled down world IMO is the dearth of readily available, inexpensive, 10" and 12" wide BW drivers.

GM
 
I've not experienced any of what you've described in my 3-way system. One of the most challenging pieces of recorded music these days is the 1812 Overture on the Telarc label. I guarantee I play it louder than 70db and I've not experienced over excursion or clipping. In fact, the cannon blasts are handled quite admirably with the Extremis handling the major part of that duty.
 
Is xmax that important for midrange? I plan on using Atlas 12's for 150-200hz and down. I figured I could get away with the 167's. Maybe the 207's would be a better idea? They've got 50% more surface area and 2x the xmax of the 167. I suppose I'd want to cross at 5k with an FT17H then.

I'm open to suggestions for alternatives for a midrange driver but I kinda wanted to stick with high efficiency drivers so I can power them with 2x25W Tripath amps in parallel. And of course plate amps for the Atlas'.


EDIT: Due to compusive buying habits, the 207's are on the way. I'll let you guys know how it turns out.
 
Actually I missed something rather important about the amp. It's 2x25W at 4ohms. It's only 2x14W at 8ohms. That's continuous average according to Tripath. I might have to take a step up the line to something more powerful. The 207's are rated for 30W.

I'd get the WR-125S, but they don't look like anything special. The response curve isn't too hot and they've got nothing above 10k, which makes a tweeter mandatory. Their efficiency is only average. They really look like Tang Bands with more xmax to me. I could be competely wrong though, and if it turns out that they're an exceptional driver, I'll buy a pair or two and put the 207's in a pair of really big back horns. For now I'll stick with a more familiar driver. A lot of guys like the 166/167 and 206/207, although no one has used it for open baffle yet. At any rate, if it doesn't work out, I'll know better for next time. They should arrive Friday and I'm going to order the Atlas 12's soon. Maybe 15's even, if they're still on sale.
 
JWFokker said:
Actually I missed something rather important about the amp. It's 2x25W at 4ohms. It's only 2x14W at 8ohms. That's continuous average according to Tripath.

Are you talking about this amp? http://www.6moons.com/audioreviews/sonicimpact/t.html
The proper way to rate an amp is x watts / channel, at rated distortion, into an eight-ohm load, both channels driven. Which makes the Sonic Impact a 5.5W amp according to the six-moons measurements.
 
They really look like Tang Bands with more xmax to me. I could be competely wrong though

Yes, you are. ;)
They look like TBs because TB manufactured them but they are in no other way like the W4s. However, this is why I asked the efficiency question. With a low power T-amp they will not perform to their potential in a large room. As an aside, I have run them with the SI T-amp and they did surprisingly well. Well enough that I had people running in from the adjoining room to find out where the sound was coming from. :)
Good luck with your project. I think it'll turn out well!
 
audiobomber said:


Are you talking about this amp? http://www.6moons.com/audioreviews/sonicimpact/t.html
The proper way to rate an amp is x watts / channel, at rated distortion, into an eight-ohm load, both channels driven. Which makes the Sonic Impact a 5.5W amp according to the six-moons measurements.


Not that amp. I do own that amp (currently out of commision due to a mod gone wrong). The one I'm referring to is the AMP3 from 41hz.com, which is rated for 2x25 into 4ohms and 2x14W into 8ohms. It uses the 2021B chip, whereas the Sonic Impact uses the 2024 chip. I should probably step up to the AMP1 (TA2022 based), which is rated for 2x50W into 8ohms, and also lower THD than the AMP3.


And thanks for the vote of confidence Timn8ter.
 

AJinFLA

Banned
2005-02-09 4:35 am
Tampa
JW,
how you been good buddy? Haven't seen you in a while, so I thought I'd drop in on this thread to see if I could help. My, my, what's all this talk about tweeters? With a Fostex "fullrange"? What's happened since our last post? A tweeter? Did you realize (just like GM pointed out also) that "fullrange" is mostly an extended range midrange, though not by too much. Mediocre bass along with rather poor treble quite often. Well thats a good start. I see you liked the pics of my "Orions" too. At least I had some positive effect on you after our last little exchange;) . Always glad to help of course. I thought the title of the post was rather strange, since the Fostex IS a midrange. Caught my eye. But now unto your design. Ok, so we have a 12" dipole sub going up to 150-200hz huh. My, my, that's awful close to your dipole resonance peak isn't it? Could be problematic. Might be ok though. So far so ok. But now you plan on using a Fostex FE207 8" midbass huh. For open baffle too? Took a look at that beauty @ Madisound myself. Let's see, real banana fiber cone - nice!. Sd 206cm^2, ok, Qts .26 ,ouch thats gonna need some serious eq. - probably 6db, along the lines of the W22 below. But you have lot's of power reserve right? 14w RMS. Driver looks pretty efficient (though not near as efficient as the TB Logitech uses: 112+db from 15w) Well, um, ok, we're still ok. But is that a misprint or does that say 1.5mm Xmax! For an open baffle driver! How wide of a baffle are you going to use? What's your SPL at 150-200Hz going to be? You know its Xmax (not efficiency) limited right? Did you plug those numbers into SL's excursion limited SPL xls. spreadsheet? What's your "D" going to be? What am I thinking, of course you did! I'm not so sure how this is going to work, but what the heck would I know. Maybe Timn8er has a thought on this. He seem's to favor the ol' full rangers also. How's a 1.5mm Xmax 8" fullranger going to fare OB? I try to stay away from these fullranger's (as you may have gathered from our last post). The distortion measurements get real nasty at each end of the spectrum. You know, like those nonlinear tonebursts we discussed before. But hey, you only spent like $180 for the pair. I don't think you could have found a more suitable OB midbass for that kind of money. Now as far as the 207 being down 12-15db off axis @ your 5k XO point (an 8" dia. driver won't break up much past 1k, so 5k is good) and the FT17 being down practically 0db off axis, well that might affect your polar response a wee bit, but I believe you said before that you only listen directly on axis, so again, the off axis ups and downs shouldn't matter much. I hope you have forgiven me for being such an ill-informed jerk on our last post. I must have been having a bad day. I'm sorry. It sounds like you have a rather fine system in the making here. Those Fostex drivers look killer. I can really see why people are enamored by the crossover less sound of the Fullrange, even though you seem to have two.
Hope we can be pal's now that we agree on so much more. No more of that cussing stuff. Post some pics of the whole rig when its done. I'd really love to see it.
Here's mine just in case you forgot.
My idea of "full" range.

Cheers and good luck

AJ:)
 

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