fostex FW208N and FF85K

[navin]

Greg, boy u are up late.....just saw that you are on PST....

it is that romantic thing i am after. that is where teh EL84s come in.

i figured the EL84s would be better mated to fostex drivers than jordan.

how big a box would the 8C require? I have used focal in the late 80s (8N515 bass reflex, 8K516J tranny line) and wonder if they are as romantic as fostex. the xo is right in the region where this difference would be audible (vocals).

also if i were to use the 85K with a woofer what would you recomend for the center and surrounds (125K, 103E)?

dont worry about sheilded. their days are numbered. today almost all HT systems use plasma, LCD, front projection.

as far as sales are concerened i would not worry about that as i am making preparations to purchase these drive units only when i visit the US (Fremont). My expected budget for the woofer is about $70 although this is flexible is the "right" woofer is found.

[navin]

just saw that Jordan JX125/53 sell for $250 a set. Even with the expensive Fostex FW208 and 2 x FF85K i'd save a lot in comparision. if i get a good woofer for $100 I'd be happy. for $130 I'd have a set and for $250 a pair. half the cost of Jordan.

[Greg B]

Greg, boy u are up late.....just saw that you are on PST....

I knew I'd get busted! Insomnia I guess.

it is that romantic thing i am after. that is where teh EL84s come in.

i figured the EL84s would be better mated to fostex drivers than jordan.

I love EL84's. One of my all time favorites, and all I listened to for years. Yes, I think you're right that the Fostex would be more suited. The Jordan nuts seem to run SS as a rule.

how big a box would the 8C require? I have used focal in the late 80s (8N515 bass reflex, 8K516J tranny line) and wonder if they are as romantic as fostex. the xo is right in the region where this difference would be audible (vocals).

The 8C is extinct I think, unless speakercity has some, but there's probably and equivalent. My enlosures are ~9x12.5x33" (OD), but these are technically 'oversized' EBS boxes.

All the focals I have used have been extremely neutral, almost weirdly so. Not romantic at all, but the most realistic voices by far. But the combo of EL84 & ultraneutral focals works VERY well. Definitely a synergy thing. Fostex and Focal are noteably both very dynamic sounding.

also if i were to use the 85K with a woofer what would you recomend for the center and surrounds (125K, 103E)?

The FF125 is a horn driver, and will give you some grief unless you put it in one or EQ it somehow, but it could work. I guess I'd try to use the same mid/high driver in all channels for best matching.

Yeah, I've had an LCD projector for several years and never actually owned a TV, so shielded drivers aren't my highest priority either.

Maybe your original idea is the best. I do sort of like the idea of all drivers from one manufacturer.

GB

[navin]

sorry i took so long to respond. I am still looking for a nice woofer that would mate with the FF85K. While budget is not a serious criteria since the FF85K is only $30 I dont want a $200 woofer it just does not look right :-)

I found this....
http://www.tb-speaker.com/detail/1208_03/w8-933.asp
other candidates....
Peerless HDS 205, Vifa Classic M21, Seas CA21RE4X (H373) and the Focal 7C/8C series that seem to be only available at zalytron (I am leaning towards the 8C012DB).

of these which of them would work best in a 20-25 liter box. WAF dictates that the box be no bigger than 25 litersanything smaller would be welcome.

LF response would be 40-45Hz with capability to deliver 95db/2m/50Hz. Is this spec too stringent for a 7-8" woofer in 25 liters?

[Greg B]

sorry i took so long to respond. I am still looking for a nice woofer that would mate with the FF85K. While budget is not a serious criteria since the FF85K is only $30 I dont want a $200 woofer it just does not look right :-)

Yeah, it doesn't seem sensible. You'd be paying for very flat 'studio monitor' type response and low distortion, but - with the FF85 - the project is more along the lines of 'ultra fi'. I think the sensible application for the FW208 would be the FT48 and the official fostex crossover and box. Fostex factory designs are very well thought out.

I found this....
http://www.tb-speaker.com/detail/1208_03/w8-933.asp

That's a non starter IMO. It's an inefficient subwoofer driver with a heavy cone. It's unlikely to mate well with the FF85, unless you were to use it as a sub, with the FF85's run in vented boxes full range. That might not be a bad approach, but it would be more SPL limited. IOW, it wouldn't play as loud.

other candidates....
Peerless HDS 205, Vifa Classic M21, Seas CA21RE4X (H373) and the Focal 7C/8C series that seem to be only available at zalytron (I am leaning towards the 8C012DB).

Any of those should work OK, except the Vifa which wants to see a bigger box (~40l). I'd be inclined to use a paper cone for better subjective matching, but the peerless is a sandwich type, and should be pistonic to 1kHz or more. Peerless are known for good bass in small boxes. The Focals are likely to sound the most realistic. Seas might be the best compromise. Tough to say.

of these which of them would work best in a 20-25 liter box. WAF dictates that the box be no bigger than 25 litersanything smaller would be welcome.

LF response would be 40-45Hz with capability to deliver 95db/2m/50Hz. Is this spec too stringent for a 7-8" woofer in 25 liters?

Yes. It's not going to happen. Hoffman's Iron Law intervenes. With a fixed box size of 25l, you have to sacrifice either efficiency or LF extension. You're looking at about 90db for that size box with that F3, and that would be with against the wall placement (shallow box). There's a chart out there somewhere. The FF85 is only 88 db anyway. Oh, but you're biamping. You could use two Focal 7C in an MTM for about 95db with an F3 of about 65hz in 25liters. In room, it'd be a bit lower.

Hope that helps.

GB

[Rudolf]

Hi navin,
since you are another strong supporter of the FF85k, Iwould like to present to you my latest configuration with this small jewel:
I combined the FF85k (in a small TQWT) with a dipole sub.

X-over is active analog 24 dB Linkwitz Riley (care of Behringer CX2310 http://www.behringer.com/CX2310/index.cfm?lang=ENG ) at 120-160 Hz. This is low enough to annihilate my dipole box resonance notch at 360 Hz and high enough to make the FF85k comfortable. Since X-over is active, I don´t care for the impedance peak @120 Hz.
The dipole sub (one for each channel because of the highish x-over, and because my equipment allowed for it anyway) is a Visaton W250 8 Ohm (http://www.visaton.de/english/artikel/art_645.htm) in a half W-frame. Sensitivity of both drivers matched perfectly, so I needn´t adjust levels at the CX 2310 in any way. Bi-amping is by vintage NAD 312 and NAD series 20 amps.
The dipole doesn´t go very low, but switching the 25 Hz low cut switch on the Behringer makes a hearable difference. The dipoles outer dimensions are 20x35x30 cm (WxHxD), keeping it in your WAF restrictions :-)

In my 6 x 4,5 m room this combination is capable of quite impressive max. SPL (more than I would want for >1 min) and the FF85k is still safely in its Xmax margin. In the next weeks I will turn the FF85K back to Open Baffle (where it has been successfully before) to get a full dipole system again.

I am a VERY close-fisted guy and this is the cheapest system that could meet my "audiophile" demands. Since the Visaton W250 is a middle of the road standard woofer, you will certainly get an equivalent with comparable Qts, Fs, SPL and Xmax in India. So why not try something like that for yourself?

Have fun
Rudolf

[navin]

Originally posted by Greg B
Fostex factory designs are very well thought out.

The Focals are likely to sound the most realistic. Seas might be the best compromise.

Yes. It's not going to happen. Hoffman's Iron Law intervenes. With a fixed box size of 25l, you have to sacrifice either efficiency or LF extension. You're looking at about 90db for that size box with that F3, and that would be with against the wall placement (shallow box). There's a chart out there somewhere. The FF85 is only 88 db anyway. Oh, but you're biamping. You could use two Focal 7C in an MTM for about 95db with an F3 of about 65hz in 25liters. In room, it'd be a bit lower.

Oh....lets refine this.....my idea was to use a box (sealed or TL or ML-TL) with say a Focal C series or Seas 373/333 or any other woofer that would mate with the FF85K. The INTERNAL dimensions of the box would be about 8"Wx30"Hx6"D (in fact I am hoping to taper the box from 3" at the top to 9" at the bottom averaging 6" D).

on top of this box I was hoping to put 1 or maybe 2 FF85K drivers on an open baffle that would be 8" wide with a 2-3" lip. There would be some back wave cancellation over the top of this baffle s the baffle might not be 8" tall.

I can draw this but to scan it and attach it is outside my skill set.

The drivers of this system are not set in stone. Even the concepts are not. I am open to and am looking at other ideas such as a push push using 2 fullrange drivers only I dont think 2 4" Fe103/107 will be able to satisfy my SPL needs. Larger drivers like the FE167 might make the box too large.

What is set in stone is the box must have very high WAF/SAF and must produce "audiohphile" quality sound. Since this will be part of an HT/AV system I would be looking at drivers like the FE103 for center and rear.

for the rear/center I am looking at a FE103/FW108 combination in about 12 liters. However since these systems will be wall mounted (the TV is plasma) I wonder if I need BSC at all. For this I am looking at something that resembles a B&W's VM1 or KEF's KHT9000.

Yes one FF85K is about 88db. 2 will be 91db. Since I am using a EL84 based amp for this I can change taps when I add the second FF85. 2 FF85K will deliver 91db/1W/1m = 88db/1W/2m. Hence with 10W they should deliver 98db/2m. 1 FF85 will deliver 95db/2m with 10W.

The woofer hence should be able to match 2 FF85K from 50Hz+ albeit using more power.

[navin]

Originally posted by Rudolf
since you are another strong supporter of the FF85k...
the dipole sub...in a half W-frame. Sensitivity of both drivers matched perfectly...The dipole doesn´t go very low..The dipoles outer dimensions are 20x35x30 cm (WxHxD), keeping it in your WAF restrictions :-)

In my 6 x 4,5 m room ...
I am a VERY close-fisted guy ...Since the Visaton W250 is a middle of the road standard woofer, you will certainly get an equivalent with comparable Qts, Fs, SPL and Xmax in India.

Gee thanks.....great idea.....I am also very tight fisted. Do you have a pciture of this. I am bit confused by your descroption.

From what I undertand you have a dipole sub using 2 10" visaton woofers measuring 8"x14"x12" on top of which you have an FF85 in a TQWT?

My proposed room will be about 3m x 6.5m with a 2.6 m ceiling so your room size is similar. I am equally tightfisted especially since each Euro is more than 50 of our Indian rupees.

I dont think I will be able to find an equivalent to the Visaton W250 in india so I might have to import it. lastly I am having another idea what is I use 4 8" woofers like the http://www.visaton.de/english/artikel/art_466.htm or
http://www.visaton.de/english/artikel/art_462.htm

(the W200 seems more suitable for dipole than the more expensive W200S).

I could make a dipole box that is 26-30" tall and 10" deep. :-)

lastly 2 unrelated questions:
1. How is your english so good. Most of my german friends (and I have a few) wrote understandable english but your's is close to perfect.
2. Which part of Germany are you? Having lived in Frankfurt and Viseren (near Monchengladbach) and visted towns like Gottingen, Cologne and Nuremberg it would be interesting.

[Greg B]

I like Rudolf's plan of the open baffle sub with the FF85 run full range. This would probably be easier, though you'd lose some efficiency dealing with the baffle step on the FF85s, and - since an open baffle rolls off 6db/oct below the baffle cutoff - it would take more power here as well. The factory fostex BR alignment for the FF85 does look a bit 'warm', so you may be able to ignore BSC. I don't need it with the FE87 in factory BR.

I have to say, i'm not a big fan of open baffle midrange/tweeter configurations, but it depends on your room. Dipole bass makes a lot of sense. You lose efficiency, but avoid a lot of room interaction problems. Most of the boxy sound I find unpleasant comes from the bass end of things.

There's also the 'sensible' approach of getting FE167E's, putting them in BR boxes, and adding a sub.

At some point, you just have to make your best guess, order the parts, and start suffering, while trying to have fun.

GB

[Rudolf]

From what I understand you have a dipole sub using 2 10" visaton woofers measuring 8"x14"x12" on top of which you have an FF85 in a TQWT?

Has been quite late last night when I tried to explain my speaker configuration. I hope a picture will clear the fog ;-)

The TQWT with the FF85K was developed with much appreciated help from GM (it was my first attempt at MLKs worksheets). The discussion was documented in some earlier thread in the fullrange-driver-forum. Maybe that is down the drain with the recent shift to a new forum format. But the plans are certainly still available from me, if anyone is interested.

The dipole bass started life as a true w-baffle according to SL. In favor of even less room interaction of the sub I splitted it in half. I plan to stack two of these "half" units and place the FF85K in a small OB on top of it.

The pictures show the actual system for one channel. Since it´s still under construction you need not elaborate on the craftmanship of the woodwork. I know how to do better! :-)

the Visaton W200 seems more suitable for dipole than the more expensive W200S.

You are right, Navin. In my configuration I have no means to boost bass electronically, so I prefer a Qts near 0.8 to get as low as possible. Qts~1.0 or even higher might be too sloppy. These drivers are far from hightech, but you will wonder what they can do in a dipole subframe.