The FF85K needs 24db/octave to be used at 300Hz? It cant do with a shallower slope?
I agree the FF85 is a lot of driver for $30. The Jordan costs 4 times as much. I have not seen the Veravox 3 (also $30) to compare; wonder if it can go lower than the FF85K.
With the intention of using one driver from the lower midrange 200Hz+ I am also investigating the larger Jordan (JX92), Veravox (5s), and Supravox (135). The Jordan might be the best bet as it's is very flexible for the kind of boxes it can be used with.
Another option might be the Fostex 103/108. Although all of these options will come at the cost of an extended treble.
I agree the FF85 is a lot of driver for $30. The Jordan costs 4 times as much. I have not seen the Veravox 3 (also $30) to compare; wonder if it can go lower than the FF85K.
With the intention of using one driver from the lower midrange 200Hz+ I am also investigating the larger Jordan (JX92), Veravox (5s), and Supravox (135). The Jordan might be the best bet as it's is very flexible for the kind of boxes it can be used with.
Another option might be the Fostex 103/108. Although all of these options will come at the cost of an extended treble.
I'll be trying the Fostex FF225K in a "Rethm the second" cabinet: the idea for it was that it was fairly similar in behavior to the preferred lowther DX4, but with somewhat lower Qts, Xmax (but in an underhung coil, Xmax means less than with overhung), and much smoother response, giving up the top octave. A Raven R1 rolled in first order at 10k ought to add just the sort of sparkle the unit needs.
Funny thing, the initial plan is to drive this speaker with the Motorola DCP501 tripath receiver: too many speakers in the house hahahahaha
$90 receiver driving some pretty fancy cabinets/drivers
You know your speaker building has gone to excess when you're about to ask your boss if you can warehouse a couple pallets worth at work
Funny thing, the initial plan is to drive this speaker with the Motorola DCP501 tripath receiver: too many speakers in the house hahahahaha
$90 receiver driving some pretty fancy cabinets/drivers You know your speaker building has gone to excess when you're about to ask your boss if you can warehouse a couple pallets worth at work
For me it was the balance between a low xo point and power handling / IM. A 4th order slope let me maximize that.
I've also tried it with 1st, 2nd and 8th order slopes. To me the 4th order sounds the best. I originally thought 2nd order would be better since it could give a better 'blend' between the Fostex and the 15s - but the 4th order seems to make the most seamless transition.
Yeah, I've looked a lot into 4 inch or larger drivers. But most of them seem to have a compromised high end. One of the reasons I find this current design so appealing is that it puts the XO into wavelengths that are very forgiving, in a sense. Based on my sims, and some feedback from a career designer, putting the XO at 300 eliminates lobing errors at the XO point.
The thought of having to roll in a supertweeter - and the impossibility of getting them aligned - puts me immediately off. A three inch driver in my mind is the best compromise for getting around the critical hearing (and design) band.
I'd like to try out some jordans. I'm not willing to spend the money on them until I've extracted every ounce of quality out of these lower priced drivers. I'm also not thrilled about the idea of an aluminum cone, although I've heard good things about the jordans.
But to answer your question, you can technically run the FF85K full range. It has a lot of xmax for a little driver (can't remember the number), so can handle just about any bass waveform (non-EQd of course) you can throw at it. It gives audible distortion on tracks that most other, larger speakers distort on.
I was originally going to use it full range with a sub rolled in, which is very possible, but I think this design is better overall.
If you're thinking about taking a full range driver down to circa 200 - I can't recommend it enough. After just a couple of weeks of testing, I think there is a lot of potential in that type of design. If you look at most graphs of excursion vs frequency, the 'take off' point is right around there - which means your bass drivers is going to still handle the lion's share of the heavy excursions. Crossed over at 300, I can't see the fostex moving.
I've also tried it with 1st, 2nd and 8th order slopes. To me the 4th order sounds the best. I originally thought 2nd order would be better since it could give a better 'blend' between the Fostex and the 15s - but the 4th order seems to make the most seamless transition.
Yeah, I've looked a lot into 4 inch or larger drivers. But most of them seem to have a compromised high end. One of the reasons I find this current design so appealing is that it puts the XO into wavelengths that are very forgiving, in a sense. Based on my sims, and some feedback from a career designer, putting the XO at 300 eliminates lobing errors at the XO point.
The thought of having to roll in a supertweeter - and the impossibility of getting them aligned - puts me immediately off. A three inch driver in my mind is the best compromise for getting around the critical hearing (and design) band.
I'd like to try out some jordans. I'm not willing to spend the money on them until I've extracted every ounce of quality out of these lower priced drivers. I'm also not thrilled about the idea of an aluminum cone, although I've heard good things about the jordans.
But to answer your question, you can technically run the FF85K full range. It has a lot of xmax for a little driver (can't remember the number), so can handle just about any bass waveform (non-EQd of course) you can throw at it. It gives audible distortion on tracks that most other, larger speakers distort on.
I was originally going to use it full range with a sub rolled in, which is very possible, but I think this design is better overall.
If you're thinking about taking a full range driver down to circa 200 - I can't recommend it enough. After just a couple of weeks of testing, I think there is a lot of potential in that type of design. If you look at most graphs of excursion vs frequency, the 'take off' point is right around there - which means your bass drivers is going to still handle the lion's share of the heavy excursions. Crossed over at 300, I can't see the fostex moving.
m@ said:
How come 300hz? I find it a little high. My requirement comes from the fact that I intend to use the same speakers for 2 ch. audio as well as 4.1 or 5.1 ch. HT/AV.
The speaker system would be centered around a fullrange that can be used for wall mounted center and rear channels without ANY bass augmentation.
The front channels would have a 12" woofer and if nesscary a helper tweeter like has been done with so many JX92 designs. It would a biamped 4 box system with 2 woofer boxes and 2 HF boxes. The HF boxes have a size limit of about 9 liters and will be wall mounted flanking a LCD TV.
My 2 choices for the fullrange was either a single 4" (the JX92) or a multiple smaller speakers (to improve power handling) like the 85K array shown in te PDF below http://www.fostexinternational.com/docs/speaker_comp/pdf/recom_enclose/fw137_fw85k_tboy.pdf
The 0.1 channel would be 2 12" woofers similar to the woofer used in the front channels.
All Amps would be solid state given size constraints.
planet10 said:
where are the details of such a system? Is the JX150 still in production?
A strange attractor is bringing all these together here on the mountain....
FE108eS is my favorite midrange (and an ideal candidate for help on the bottom), and a pair that needed some TLC came my way... they now have phase plugs (fixed the problem with the dustcaps) and will be guinea pigs for some C37 that also found its way here. The ribbons were a bribe for some work i did, and the JX150s a payment towards some work i haven't done yet.
dave
FE108eS is my favorite midrange (and an ideal candidate for help on the bottom), and a pair that needed some TLC came my way... they now have phase plugs (fixed the problem with the dustcaps) and will be guinea pigs for some C37 that also found its way here. The ribbons were a bribe for some work i did, and the JX150s a payment towards some work i haven't done yet.
dave
No JX150 -- they are made of unobtainium these days. Due to being cash poor, i had to sell the pair i had bought so long ago... but 3 more -- all with some small problem to fix (making then not worth selling) -- just came into my possession... it is like i'm destined to use a pair.
The system isn't so much being designed as it is coming together organically.
JX150s will either be in a sealed box -- or more likely a TL -- i have a triangulated design on the books already. Something that drags as much bass out as possible but with close to critical Q. The FE108 are crying out for some sort of low resistance box... because the other elements are mono-pole something that reduces rear output so think cross between an OB and an aperiodic TL. XO at the bottom of FE108eS will be determined by where it starts to roll off, i'm guessing that will be 200 Hz or so. I'll add a 1st order pole in the amp (likely an SE tube amp so this is achieved with a smaller than usual coupling cap). Placement of a single pole on the top of the mid amp determined by how low i figure i can safely XO the ribbon 2nd order (1 pole in a EL84 SE in the same manner as the mid amp -- i have a lovely set of tweeter amp OPTs + a blocking cap in series with the tweeter). XO on the Jordans will be determined by what it takes to get them to blend with the Fostex... with response to 8-10k it should be doable.
At the moment a shape something like the Sonus Faber Stradivaria -- a wide baffle fading back from the middle so that the baffle step loss on the FE108eS is at or below its cutoff. The reverse effect on the upper part of the JX150s response will have to be dealt with in the XO.
This may all also be augmented by a (real) subwoofer utilizing the unused space near the ceiling of my lab downstairs which just happens to have a common wall with the listening room -- 4 or 8 12s or 15s could provide an effortless bottom octave or so.
The best amp we have done so far for bass is a 4W PP tube amp... we'll need a bit more power than that, so further development along those lines is currently indicated, but we do keep trying to find a SS amp with similar finesse.
I'm in no hurry to get this together... and it seems to be coming together on its own and will likely evolve furthr from the current visualization.
dave
Because my OB starts to roll of around there. I wanted my big drivers to handle all EQ duty. If the FF85k could handle EQ, I'd probably shoot for 200.
If you're not using them OB, you can go to 200, I would guess. 200 for surround speakers, no problem.
You ever go up to Darjeeling? Man, that's a beautiful place.
m@ said:
I would most porbably be using them in a sealed or aperiodic box.
Right now the debate in my head is between the raggedness of the JX92's HF response vs the polar interference I can expect to face with 4 FF85K in a line array. I figured is 1 FF85K can be used to 200hz then a line array of 4 can be used even lower (maybe even 100Hz).
I am leaning towards the JX92 with the thought that if I find the HF too harsh I would get a pair of tweeters and use them in a 2 way for atleast the front left and right channels (which would be used for 2 ch. CD Audio).
The only fullrange I have heard is the JX92 (not counting some large PA speakers).
I would love to hear the Veravox 5 or Supravox 135 in case they have a smoother HF response than the JX92 and can be used as low.
Cost wise 1 x JX92 or Veravox 5 or Supravox 135 = 4 x FF85K or Veravox 3.
I have not been to Darjeeling. I hear it used to be beautiful but has become too touristy today. When did you go there?
Other places worth visiting before they are "touristised" would be Munnar in Kerala, Kodaikanal in Tamilnadu, and some of the beaches in South Goa. Let me know (via email/ PM) if you ever plan a trip to India and need help.
I'm not sure of your power handling requirements, but don't let the numbers on the FF85k put you off. They can make it to 200 sealed. They are also much louder than the numbers would suggest - but those numbers are for running them full range, as far as I understand it - running them rolled off makes a difference.
The strength of this driver, and others like it I would imagine, is that you can end up with a very clean two-way. Given the clarity of voice, I think it would be ideal for HT.
The highs are clean, but they might not be what you're looking for. In my current setup (with quite a bad DAC) they're not very hi-fi sounding. I'd call them natural sounding. I'm not sure how much of that is my crappy DAC. They're not rolled off though, they actually peak a bit between 10 - 20k.
Anyway, Fostex doesn't have me on retainer, so I'll stop promoting their products.
I was in Darjeeling years ago - just after I finished uni. It didn't yet seem overrun by tourists - but it was so foggy I couldn't see anyone anyway. I did make it to some peak in the early AM and the sky cleared enough to see everest. That was something.
Thanks for the invite. Drop me a note if you ever come to Bangkok. as well.
m@ said:
THe FF85K line array (or single JX92) would be driven by a Marantz SR7000 Reciever or similar machine. I would assume I'd be happy if they cam handle 15-20W rms each.
I saw that peak 10-20K and wonder if that would not be reduced thanks to polar interference in a line array. I have no experience with line arrays though so I dont know how this will affect the FF85K and to what degree. I wish there was a line array forum.
Thanks for the news about Darjeerling. My family does intend to visit it some time soon. Thanks for the invite to Bangkok too. It is not very far from where we are.
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