Comparing the FF85K with the Visaton FRS8M - they're virtually identical in all parameters, except that here in Aus the FRS8M is lees than half the cost of the Fostex.
The differences are in the detail of the FR graphs, the FF85K having a broad shallow dip in the 1-3K region, and a gently rising peak from 10-20K; the FRS8M has a bit of a peak at 10K, otherwise very similar to the Fostex. I'd say it'd make a good alternative.
The differences are in the detail of the FR graphs, the FF85K having a broad shallow dip in the 1-3K region, and a gently rising peak from 10-20K; the FRS8M has a bit of a peak at 10K, otherwise very similar to the Fostex. I'd say it'd make a good alternative.
They are in stock in Melb., will try to get a pair to try, if they are any good will let you know.
Maybe Scott will chime in... he has a pair of uFonken (Built here and shipped over) and i believe also tried the Visaton, My impression from his comments were that the Visaton is nowhere near...
I've not looked at the FR8 (not readily available here), but ihave done mFonken size boxes for many drivers -- with 1 exceptioneach one required different tuning for each different driver (EL70 & Alpair 6 use the same tuning)
dave
I've not looked at the FR8 (not readily available here), but ihave done mFonken size boxes for many drivers -- with 1 exceptioneach one required different tuning for each different driver (EL70 & Alpair 6 use the same tuning)
dave
I've had a pair of the FRS8Ms through here a little while ago. In fact, I've still got them in their boxes somewhere. In out & out performance terms, the FF85K is in a completely different class (although note that mine have Dave's full treatment). The Visaton's reasonable for the price. Sound-wise, it's acceptable -if you'e making some cheap speakers as gifts, you could do worse.
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From the speakers spec alone the 2 drivers seem identical, assuming the spec from FRS8M's manufacturer is accurate. You notice a difference in the sound reproduction, can I surmise that this is caused by the different materials used to build these two drivers? I strongly suspect so.
Factory specs MAY give you a vague idea of a driver's performance...but as often as not, NOT. Largely because they are VERY incomplete.
dave
I've got the Visaton FRS8 (without M), an old Fostex FE83 and Fostex FF85K. The FRS8 and the FE83 are somewhat in the same league, but the FF85K is as far above them as the price difference suggests. For instance I notice that the FF85K is beaming significantly less than both other drivers, although the geometry (size etc.) is almost the same.
Rudolf
Rudolf
Forgive my newbieness, I'm wondering if I can build the MJK h-frame passive design with the FF85k and 15a without changing the crossover of the original
design. Or perhaps I would need to exchange the 150uf low pass capacitor for a 125uf capacitor?
I want to build the h-frame instead of the straight baffle design for the extra bass, which, even though I've obviously never compared the two speakers, I feel I will need. Thanks in advance for any suggestions.
Recently built the H-frames for the Alpha's (using them as subs with the missises Tannoys (Reveal R5A's), got to say brilliant design, built in a day, £25 for the wood including all cutting, £104 for the drivers and £75 for a CX2310 crossover, £200 for TWO 15" subs
), driving them with the power section of an Audiolab 8000A.
I am curently using the left over wood (LCE) to make 2 sets of baffles:
1. For my pair of FE166's standard with P10 phase plugs
2. For a pair of FE207, full P10 treatment with FT17's
The set up will be active using initialy the CX2300 (later the DCX2496, when funds allow) with Single ended EL34 (triode mode) monoblocks for the Fostex's and the Audiolab (initially) for the Alpha's.
This gives me the chance to determine which set up I prefer and to do some experimenting. When I have decieded which set up to use I propose to build a complete OB with the U-frame, as the H-frame is causing a tiny bit of friction, due to its size.
As soon as its all up and running I'll post some listening impressions, though I'm well impressed with the Alphas already.
I'm also thinking of using a single ended class A SS amp for the Fostex's at some point, probably one of Mr Passes designs, any recomendations on which one would be gratefuly received.
NB. The crossover cost me about the same as the components for the passive crossovers would have.
), driving them with the power section of an Audiolab 8000A.I am curently using the left over wood (LCE) to make 2 sets of baffles:
1. For my pair of FE166's standard with P10 phase plugs
2. For a pair of FE207, full P10 treatment with FT17's
The set up will be active using initialy the CX2300 (later the DCX2496, when funds allow) with Single ended EL34 (triode mode) monoblocks for the Fostex's and the Audiolab (initially) for the Alpha's.
This gives me the chance to determine which set up I prefer and to do some experimenting. When I have decieded which set up to use I propose to build a complete OB with the U-frame, as the H-frame is causing a tiny bit of friction, due to its size.
As soon as its all up and running I'll post some listening impressions, though I'm well impressed with the Alphas already.
I'm also thinking of using a single ended class A SS amp for the Fostex's at some point, probably one of Mr Passes designs, any recomendations on which one would be gratefuly received.
NB. The crossover cost me about the same as the components for the passive crossovers would have.
The original project calls for the Erse Super Q inductors. Would it be okay to substitute the I Core inductors? AWG would change from 16 to 18.
Here are the ones I'm referring to:
Parts-Express.com: 9.0mH 18 AWG I Core Inductor | POwer Wire power inductors inductor handles handle gauge DC CTS
Parts-Express.com: 4.0mH 18 AWG I Core Inductor | POwer Wire power inductors inductor handles handle gauge DC CTS 4 gauge
Thanks
Here are the ones I'm referring to:
Parts-Express.com: 9.0mH 18 AWG I Core Inductor | POwer Wire power inductors inductor handles handle gauge DC CTS
Parts-Express.com: 4.0mH 18 AWG I Core Inductor | POwer Wire power inductors inductor handles handle gauge DC CTS 4 gauge
Thanks
Mr. Fur,
Only you know what your budget looks like. However, if you would like my opinion, I'd go with the Erse 16 gauge inductors. I'll probably get a lot of flack on this, but in my opinion, based on a lot of experimenting over the years, is that Inductors are much more significant in the resulting sound of a crossover than capacitors are. I'd get the Erse inductors and to save money, use bipolar electrolytic capacitors with very small value Dayton Poly bypass caps (bypass caps are usually a good idea no matter what the main caps are).The caps can be replaced as time and money is available and offers the benefit of proving to yourself if (or which) caps in a crossover enhance the sound.
Best Regards,
TerryO
How many people have built these on either 18 Goldwood or Alpha 15 ?
I think Martin has nailed the bass here, so I want to try OB again.
I am about to take the plunge and start ordering drivers. I most likely will use the ff85k. Trying to choose between 15 and 18. I will most definitely bi amp.
Thanks
Ed
I think Martin has nailed the bass here, so I want to try OB again.
I am about to take the plunge and start ordering drivers. I most likely will use the ff85k. Trying to choose between 15 and 18. I will most definitely bi amp.
Thanks
Ed
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