Fostex F200A

jgpmhl · « **on:** 20 Apr 2006, 03:45 am »

Hi,

I am considering building the recommended cabinet design for the Fostex F200A full range drivers. Has anyone out there any experience with these drivers? How do they compare to Lowther full range products (besides drier marketing)?

I am also looking into building the boxes out of glass, very thick glass. I figure this material is about as dead as it gets. Thoughts?

Thanks.

JGP

Dmason · « **Reply #1 on:** 20 Apr 2006, 04:16 am »

In my experience, the F200 do do bass, at the complete cost of the midrange. Comparatively, it simply does not exist, in my opinion, and experience, having used them in bass reflex, Bob Brines Tl, and backloaded tractrix horn, which was best of the lot, and allowed me to sell the drivers in a load, for a profit. It is a very well made clone of the JBL LE8, a late '60's-70's design, and very expensive. I strongly recommend there are far better solutions for le$$.

Prepare to use a very good source or the metal dust cap will be the sonic equivalent of the Martian Heat Ray. You will need at least 40 watts of very clean high current power to do them justice.

If I were to build a glass box speaker, I would use two Visaton B200, the lower one LP @300Hz, sealed, with two ScanSpeak aperiodic vents on the back. It would sound even better than it looked. The four drivers would wind up $280 less than the F200A.

Wind Chaser · « **Reply #2 on:** 20 Apr 2006, 05:17 am »

While I have not heard the F200A, I know Dmason is pointing you in a very good direction. The Visaton B200 is an amazing driver. Extremely revealing and the tone... oh the tone... tone to die for... I have paid a lot more for a lot less. The B200 is a gift. It's way more efficient than the F200A, which of course opens up way for far more options in high quality amplification.

Should you be open to exploring the B200, I would suggest foregoing the box and go open baffle. That may seem a little radical, but I highly doubt you'd regret it. I have experimented building enclosures with a few different materials including stainless steel. As the steel cabs are semi cylindrical, they epitomize rigidity. Unbelievable bass. By far the best sounding enclosure I have ever heard, but alas, still an enclosure. An enclosed speaker no matter how exotic the materials will exhibit certain unnatural characteristics that make it easily identifiable once you hear an open baffle. Dare to tread the path; you’ll never look back.

That's my ten cents.

Dmason · « **Reply #3 on:** 20 Apr 2006, 01:29 pm »

WIndchaser is correct. The very best kind of glass box is none at all. Make a flat baffle of glass! Better yet Kevlar.

If you have budgeted $750 for Fostex drivers and more for tempered glass, then you can easily push the speaker budget a few bucks higher, and forget all about glass houses. Here is what I am planning for this summer, and would recommend: 4 pairs of Visaton B200, LP the lower 3 ~300Hz, mount them vertically above one another on a 45 inch high, mounting the lowest one 1 inch above the floor, a 15 inch wide baffle with 15 inch wings. This implementation will yield a VERY useable 97db SPL, will employ floor lift with the ground-plane and wings giving a very good bass heft to below 40Hz, and could easily be cracking your living room walls with 2 watts, allowing you to later budget for a small SET amp. B200 with SET is just amazing. Open baffle that sound and you are so far beyond whatever you have heard in an audio emporium that...

Wind Chaser · « **Reply #4 on:** 20 Apr 2006, 04:10 pm »

Open baffles are not exactly well known but that does not negate their superiority and cost effectiveness, not to mention the simplicity of building them. Loudspeakers by far, more than any electronic component (or even the sum of electronic components, cables and tweaks) will determine the quality of sound in any given system.

I'd much rather listen to the B200’s in OB with a cheap 10 year old all-in-one Sony mini HiFi, than my Jordan full range drivers in steel cabs driven with a vastly superior electronics. There's just no comparison. I know that may seem difficult to wrap ones head around, but traditional speakers, planners included, do not satisfy after one has had the pleasure of an OB experience with a dynamic driver. Whereas OB’s open up and liberate the sound, enclosures confine and strangle the sound. And there isn’t any source, analog or digital, there isn’t any amp, SS or tube, which can compensate for the effects of an enclosed speaker. It’s really something to experience.

Dmason · « **Reply #5 on:** 20 Apr 2006, 05:16 pm »

WIndchaser,

I hadn't realized your conversion had been so complete. Sounds like you are well past the Gates of Damascus, as far as OB sonics go.

The fantastic thing about B200 on OB is that the effect is magnified, as in magnificent, as you add more dynamic B200 cones to the baffle. I have two going right now, this minute, with the ClariT, and the resolution, warmth, and just plain listenability is almost unbelievable. -Richard- is having new baffles routed this week for two B200. He is using the new Music Reference 245.1 45SE amp w/ the EML Smoothies, and complains about not being able to focus on other things, the music is sooooo... interactive with the audience. I see 4 pairs of B200 as a significant improvement over the DarkStar implementation, and W-baffle bass loads, because it is simpler, more homogenous, better sounding, less expensive, higher SPL, you name it. Better. The DarkStars are one amazing speaker set, if I may say so, and the 4XB200 is going to be even better. How's that for an endorsement for saving $ on the F200/BR idea

chadh · « **Reply #6 on:** 20 Apr 2006, 07:53 pm »

My apologies if this question sort of veers on a tangent to the original one, but this open baffle thing leaves me a bit baffled.

If I knew nothing about speaker design (well, that "if" is pretty redundant), and I happened to have a couple of drivers lying around, and I just happened to get it into my mind to build a pair of speakers, I'm pretty sure that in my complete ignorance I would build a pair of speakers in an open baffle.

I can only imagine that, way back in the deep dark ages, people with experience almost as negligible as mine, did the same thing. Open baffle speakers are "primitive", and one would expect that they were the focus of much experimentation very early on in the development of sound reproduction.

But the subsequent development of the art of speaker design has been away from open baffle speakers. And this movement appears to have been far more profound than the movement away from tubed electronics, or away from vinyl. I think I've seen reference to only two manufacturers who make open baffle speakers. And one of these is a VERY new operation.

So, my question is why essentially nobody manufactures open baffle speakers when the claimed benefits of them are so overwhelming?

I don't doubt that open baffle advocates love the results of listening to their open baffle speakers; and I'm happy to believe that there are lots of good things about them that make them appealing. But it defies common sense to think that they can do everything better than speakers in boxes. So what are the (relative) weaknesses of these designs that have encouraged essentially all modern, professional speaker designers to overlook them?

Chad

miklorsmith · « **Reply #7 on:** 20 Apr 2006, 08:23 pm »

Open baffles have stricter placement requirements. It would be tough to sell a few drivers and a board for $20k. OB's have issues with low bass and Americans Love Their Bass. They will not fit on cute stands. They do not represent "the state of the art" and all the upgradeitis going along with that.

And, with AC artisan Dmason giving beta away for free, what's the point?

nodiak · « **Reply #8 on:** 20 Apr 2006, 09:17 pm »

Hi Chadh, I didn't need to be crass in replying to your post I'm sorry. I let some recent life bumps get to me recently and shouldn't have tried to talk audio today.
I deleted my post but will have some more helpful things to say about the Hawtorne Augies atsomepoint. They are worth a look.
Don

Dmason · « **Reply #9 on:** 20 Apr 2006, 09:36 pm »

Chad,

You answered your own questions, essentially. What is left is the impressions the ear makes upon the brain. I see it time and again. Fact is a given driver simply sounds its best on a flat plane, with static air masses on each side of the diaphragm. No loading, no impedances, no back wave, no resonances no -- thing. ...OB sonics are like a lightning strike from the Cloud of Revelation. Once the brain says, "I get it," and as it has been written many times on audio boards, ...they seldom wish for a return.

A very good, well implemented OB design would be 4 B200 and 4 18 inch Real Bass Drivers. Two separate systems, bi-amped, EQ'd to the room, 300 watts on the bottom, about 5 on the top. Rent a room at the next high end audiophooleria, and Watch What Happens. At some point, I may do just that. Show up in rubber boots with plywood, and Rule. I was in a very high end audio salon on the weekend, listening to a $40,000 spread. Very hi fi. Very un-musical. A pair of B200's with a battery powered T amp would KILL that shiny yuppie crap I was subjected to. Why do I say this? Because I have seen it happen again and again now, for about three years.

chadh · « **Reply #10 on:** 21 Apr 2006, 06:32 am »

Hey Don,

Thanks. Not that a "crass reply" is such a terrible offense. But your subsequent note really made me smile and think how great it is when people care enough about these weird, disjointed communities to be sensitive to what they say and how they say it. I'm truly glad that you're enjoying your open baffle arrangement so much, and hope that it helps at least a little with those bumps life is throwing your way.

I admit to suffering as an extreme skeptic. When somebody tells me that option X is simply superior to all other options in some (any) field, I'm unlikely to believe it. When option X is cheap, extremely easy to implement and is overlooked by essentially every appropriately trained expert, it becomes even harder to believe. This is how I feel about open baffle speakers.

It's easier for me to believe that OB speakers display strengths and weaknesses relative to other options, and that some people feel that the strengths outweigh the weaknesses. Not surprisingly, others would disagree. That sort of disagreement appears when people talk about single driver speakers, about the relative merits of tubed and solid state electronics etc. But ultimately, out of those disagreements an understanding develops about the relative strengths and weaknesses of the various approaches. I'm just hoping to understand the weaknesses of open baffles so that I have a feeling for the trade-off one makes when pursuing the OB path.

Cheers,
Chad

BrunoB · « **Reply #11 on:** 21 Apr 2006, 01:09 pm »

Here is an expensive OB dynamic system:
http://www.jamospeakers.com/Default.aspx?ID=5755

Bruno

chadh · « **Reply #12 on:** 21 Apr 2006, 01:32 pm »

Quote from: Dmason

Chad,
What is left is the impressions the ear makes upon the brain. I see it time and again.

My commiserations, Doctor. It's times like these I'm glad not to be in the medical profession. At the sight of impressions made by an ear on a brain, I expect I'd lose my breakfast.

Chad

Dmason · « **Reply #13 on:** 21 Apr 2006, 01:44 pm »

Chad,

You spelled comiseration wrong.

I acknowledged your query with a fairly detailed response, and ..."sarcasm?" Hmmmm, someone takes their audio toys seriously enough for this type of behavior.

Healthy skepticism is healthy, a sign of a scientific mind. "Extreme skepticism," as you describle yourself, is a sign of resistance to change. Someone whom feels challenged by The New. Get a cheap driver from Parts Express, slap it on a board, and see how good it can sound. That is pretty much what I did, satisfied my skepticism, and my board-certified scientific mind.

miklorsmith · « **Reply #14 on:** 21 Apr 2006, 02:22 pm »

How about Soundstaging and Imaging - two militantly pursued concepts of esoterica? I would bet that OB's in general, especially in the multi-driver arrangement earlier described, would score poorly.

Well-heeled audiophiles would scoff, good sir! As for me, once I discovered Tone and Dynamics, I couldn't care less about the other two. The former are objects of intellectual pursuit while the latter incite love and affection.

HARD LEFT

As to the box/no box question of superiority, how many of the Openly Baffled have heard Druids or Definitions? I haven't heard OB's but a lot of the strangulation attributed to boxes here I related to speakers with heavy XO's which happen to reside in boxes. Of course, Louis' work does not suffer such. Maybe those comparisons are the closest I'll get.

Dmason · « **Reply #15 on:** 21 Apr 2006, 02:34 pm »

Miklor

You really hit a point there. The no XO loads-in-boxes have the least constrained sound of all. I have been listening to Louis' SuperHemps for a couple months now, and with the Big 3 inch Port, which has a DIA more like 7 inches, it does far more than simply vent the box, an awful lot of higher FR gets out, radiating. In this respect, I have to say that the SuperHemp, also with their WIDE 15 inch baffle are the closest thing in my experience, to no box at all, in terms of a bass reflex aligment, ie, very very much a departure from experience, and from expectation. Add a very very inert box, minimize resonances, and backwave attenuation, and you get a VERY good compromise. Plus, it hits an easy 35Hz using 2 watts SET. A fun situation. I like both.

I may like 4 X B200 even more. My idea is to use a simple single tone stack for <100Hz...My scientific mind wont know until it is tried, is the point. After my not insignificant additional driver purchases, time spent, tweaking, I would, of course, as usual, share ALL findings on AC, and welcome all ...responses, in order for them to benefit from my efforts as usual, and allow them to respond negatively, if they wish.

mcgsxr · « **Reply #16 on:** 21 Apr 2006, 02:48 pm »

A valid question, this one about why OB, since all speaker development seems to be in the opposite direction...

I guess it comes down like this - large displacement engines ruled the roost 70, 60, 50, 40, even 30 years ago. Now there are biturbo, supercharged, and high revving motors all with tiny displacement that get the job done.

And then there is the Viper...

I guess, there is more than one way to skin a car or audio cat, and lots of folks seem to prefer one over the other.

For me, the sheer simplicity of connecting a driver to an amp, on a panel, and getting excellent results, has stopped me from investigating any other way to make sound above 100Hz, as a DIY guy.

The ROI is stupendous...

miklorsmith · « **Reply #17 on:** 21 Apr 2006, 03:09 pm »

Hey, my point was not to discourage the thought of paralleled OB drivers at all, merely to speculate why audiophiles may perish the thought.

I think it's a great idea. Reduced cone movement per driver = lower distortion and more drivers equate to more total air moved which should increase overall tonal penetration, which is something the Def's do exceedingly well and is notably absent from nearly all speakers I've heard, comparatively.

A larger "soundwall" might increase apparent stage size. Even if the "pinpoint" location is reduced, who cares? No, this seems like a great idea indeed.

How about substituting the F200A's for the Visatons? (moment of supreme density)

Dmason · « **Reply #18 on:** 21 Apr 2006, 03:11 pm »

Return On Investment is perhaps the highest of all. Over the moon on that point.

Screw a 15 inch pro audio driver into the annulus of a 15 inch Sono tube, and there is your bass engine. This was a recent revelation as well. You could wrap it in veneer and call it a High End Bass Augmentor. Put some brass feet on it and sell it for a grand.

JeffB · « **Reply #19 on:** 21 Apr 2006, 04:31 pm »

I suspect open baffles are not so common due to aesthetic reasons. A wide baffle is needed in a world of narrow baffle speakers to fit next to a television. Also the open back may not have good WAF.

I would love to try an open baffle setup, but there are some things keeping me from it.

1) I have limited space, thus requiring a narrow baffle. This will severely limit the bass response. I expect a cut-off around 300Hz.

2) I am not sure how to fill in the bass response, because a) the cut-off frequency is a little high for most sub-woofers, and b) I still need a stereo image between say 80Hz and 300Hz. I could create two boxes with an 8" driver in each, but that would seemingly negate many of the effects of going open baffle. Cabinet vibrations are most notable in the lower frequencies.

3) I worry about needing baffle step correction. Perhaps a Behringer EQ would help here.

4) No 30-day trial period.

5) Even with all the positive comments, I worry about the quality of the high frequencies and dispersion of high frequencies. With an 8" driver I worry about upper midrange detail.