I know a few of you have used the older Foster driver with alnico magnet in the BHorn II, and since I now have a pair coming my way, I was wondering what tweaks you have found work best with this particular driver. There's next to no specific info on this driver out there, and I do plan to do some experimenting of my own, but I'd love to do so with a base of information to stand on to begin with.
The speakers will be wired with Audio Note SPa silver cable and driven with a 2A3 stereo amp I have yet to build (Quest Silvers applied gently in the mean time), and an Audio Note Kit Pre or M3 Phono at various times. The front end is either an AN CDT Two MkII and DAC 3.1x Balanced or a Voyd Table, AN-1S arm and IQ3 or IO 1 cartridge and AN-S3 mc xfrmr.
The speakers will be wired with Audio Note SPa silver cable and driven with a 2A3 stereo amp I have yet to build (Quest Silvers applied gently in the mean time), and an Audio Note Kit Pre or M3 Phono at various times. The front end is either an AN CDT Two MkII and DAC 3.1x Balanced or a Voyd Table, AN-1S arm and IQ3 or IO 1 cartridge and AN-S3 mc xfrmr.
FE103"A" in BhornII
If you bought the drivers from Dave Dlugos (Planet10) without the wooden phase plugs, shame on you.
If not, order a set of the plugs straight-way.
He and I have used this driver in various enclosures over the past few years, ranging from Bert D's cute little folded TQWP, Fostex's factory recommended ( Nagaoka designed) BLH "type", to the Buschorn. I may have missed a design or 3, but I think it's dafe to say that the best we've heard them is in the BHII.
Since you're reasonably assured the drivers are fully broken in (after only 30 or so years), there's really only a couple of tweaks needed;
1) Did I mention phase plugs? These made a huge difference in my system ( EL84 triode/PF monoblocks); opening up the midrange significantly and dramatically improving the off-axis dispersion, image stability and depth. We experimented with "helper" tweeters above 10K, but with any reasonably decent front end, and a SET as transparent and dynamic as EL84 or 2A3, it was hardly worth the trouble. (300B amps could be another story)
2) Apply a thin layer of Duct Seal ( Ideal Industries 31-601) to the stamped frame, in particularly filling the gap between the rear of the basket and magnet loop. The goal is to make as smooth a transition as possible. Maybe Dave can post a picture of a suitably modified driver.
The enclosures themselves benefit from sand filling of the large internal and lower fold voids - a little harder to install after the boxes are glued up, but where there's a will .... I used "Tru Grit" (really) sand-blasting abrasive.
If you haven't built the boxes yet, don't waste your time with any material other than Baltic Birch. Due to the amount of bracing from the internal folding panels, you could probably get by quite nicely with 15mm (approx 5/8"). A small hardwood or 3/4" brace across the final mouth of the horn doesn't hurt either, and makes for a convenient hand-hold when moving.
The trickiest part of voicing the speaker is damping the compression chamber. Some folks have experimented with blocking it off entirely when using the FE108E Sigmas, which I had myself, until very recently. I didn't care at all for the results, and went back to about 2/3 stuffing with 1/2" acoustic felt (also from the "frugo-phile" audio recycling guru), but YMMV.
As for placement, I have been happiest over the past 5 years or so with a placement diagonal across a room corner; i.e. the line forming the front baffle of the enclosures forming the base of an equilateral triangle, with the corner as the apex.
Due to the rear mouth of the BHII, you'll need to experiment with distance from the side walls ( I'd suggest starting around .5 - .75M) and toe-in.
Enjoy, and smile when your guests ask where the "other" speakers are
If you bought the drivers from Dave Dlugos (Planet10) without the wooden phase plugs, shame on you.
If not, order a set of the plugs straight-way.
He and I have used this driver in various enclosures over the past few years, ranging from Bert D's cute little folded TQWP, Fostex's factory recommended ( Nagaoka designed) BLH "type", to the Buschorn. I may have missed a design or 3, but I think it's dafe to say that the best we've heard them is in the BHII.
Since you're reasonably assured the drivers are fully broken in (after only 30 or so years), there's really only a couple of tweaks needed;
1) Did I mention phase plugs? These made a huge difference in my system ( EL84 triode/PF monoblocks); opening up the midrange significantly and dramatically improving the off-axis dispersion, image stability and depth. We experimented with "helper" tweeters above 10K, but with any reasonably decent front end, and a SET as transparent and dynamic as EL84 or 2A3, it was hardly worth the trouble. (300B amps could be another story)
2) Apply a thin layer of Duct Seal ( Ideal Industries 31-601) to the stamped frame, in particularly filling the gap between the rear of the basket and magnet loop. The goal is to make as smooth a transition as possible. Maybe Dave can post a picture of a suitably modified driver.
The enclosures themselves benefit from sand filling of the large internal and lower fold voids - a little harder to install after the boxes are glued up, but where there's a will .... I used "Tru Grit" (really) sand-blasting abrasive.
If you haven't built the boxes yet, don't waste your time with any material other than Baltic Birch. Due to the amount of bracing from the internal folding panels, you could probably get by quite nicely with 15mm (approx 5/8"). A small hardwood or 3/4" brace across the final mouth of the horn doesn't hurt either, and makes for a convenient hand-hold when moving.
The trickiest part of voicing the speaker is damping the compression chamber. Some folks have experimented with blocking it off entirely when using the FE108E Sigmas, which I had myself, until very recently. I didn't care at all for the results, and went back to about 2/3 stuffing with 1/2" acoustic felt (also from the "frugo-phile" audio recycling guru), but YMMV.
As for placement, I have been happiest over the past 5 years or so with a placement diagonal across a room corner; i.e. the line forming the front baffle of the enclosures forming the base of an equilateral triangle, with the corner as the apex.
Due to the rear mouth of the BHII, you'll need to experiment with distance from the side walls ( I'd suggest starting around .5 - .75M) and toe-in.
Enjoy, and smile when your guests ask where the "other" speakers are
Oops, not Foster - likely panasonic/matsushita
Actually, these aren't coming from Dave, but I tripped over his site, and it was in ordering the phase plugs that he informed me that the drivers weren't what I thought they were. Once the drivers get here, I'll measure and order up.
Nope, cabs aren't built yet, and I've read through your site, Dave's and a few others. Baltic birch was a given from the get go. I don't want my music to sound dead, which is what I always hear from MDF.
Sand is in the picture, as will be outrigger spikes since this speaker can't possibly be really stable on carpet.
Yeah, I can see from reading up that fine-tuning the size and damping of the cc will be critical. One side will be screwed on and finishing will have to wait a while. ;-)
Strangely enough, the speakers I sell in "real life" are designed for corner placement as well, which always gets the high end crowd's shorts in a knot.
These speakers will probably go with me to the Great Plains Audio Fest April 29 - May 1 in Tulsa OK. By tomorrow the beginnings of the site for the show will be up at www.greatplainsaudiofest.com
Actually, these aren't coming from Dave, but I tripped over his site, and it was in ordering the phase plugs that he informed me that the drivers weren't what I thought they were. Once the drivers get here, I'll measure and order up.
Nope, cabs aren't built yet, and I've read through your site, Dave's and a few others. Baltic birch was a given from the get go. I don't want my music to sound dead, which is what I always hear from MDF.
Sand is in the picture, as will be outrigger spikes since this speaker can't possibly be really stable on carpet.
Yeah, I can see from reading up that fine-tuning the size and damping of the cc will be critical. One side will be screwed on and finishing will have to wait a while. ;-)
Strangely enough, the speakers I sell in "real life" are designed for corner placement as well, which always gets the high end crowd's shorts in a knot.
These speakers will probably go with me to the Great Plains Audio Fest April 29 - May 1 in Tulsa OK. By tomorrow the beginnings of the site for the show will be up at www.greatplainsaudiofest.com
Re: Oops, not Foster - likely panasonic/matsushita
Welcome o the forum Dave.
More later... gotta go fix a set of isophone coaxes...
It is syncronystic that the local hifi dealer is a big AN fan/seller... Chris has built up a couple of the boxes for the kits.
dave
Cal's 10F3s with the major teaks....
dave
Welcome o the forum Dave.
DRCope said:
More later... gotta go fix a set of isophone coaxes...
It is syncronystic that the local hifi dealer is a big AN fan/seller... Chris has built up a couple of the boxes for the kits.
dave
Cal's 10F3s with the major teaks....
dave
And speaking of Cal's FE103As.... here is a pic of them in his new "Jimmy Buffet" 4-ways (or maybe 3.5 way). They are actually just place holdng for a pair of Coral 103As which -- unmodified & with a bit of "stiff surround syndrome" -- he liked better than the tweaked Fosters. His Corals are over here for surround resurrection and tweaks including phase plugs.
Dave's 103As, to my best guess, are also Corals and very similar to Cal's, the prime difference being the baskets.
Also of note in Cal's JBs are the Foster inverted dme tweeters. These are the only ones i have ever seen and look really nice (and Cal says they sound really good too)
dave
Dave's 103As, to my best guess, are also Corals and very similar to Cal's, the prime difference being the baskets.
Also of note in Cal's JBs are the Foster inverted dme tweeters. These are the only ones i have ever seen and look really nice (and Cal says they sound really good too)
dave
Attachments
Here is a pic of the Corals (i'm going to call them that, but still have some suspicions they may actually be Panasonic/Matsushita -- note that these were the guys that pushed FR tech the furthest of any of the big 3 OEMS)... note what looks like may be the points of ribs sticking out from under the dust cap)
dave
dave
Attachments
and a group photo... mostly Foster FE103As ... of special note are the set on the lower right, these are a Canadian made Radio Speakers of Canada variant found i a set of the trendy Electrohome speakers -- unfortunately foam surrounds that are now dust. Since this pic was taken i've gotten at least 3 more flacvours of Corals (2 of those are singles), 2 more flavours of Foster, and the Panasonics above. Dave's are another i haven't seen. I mention numbers because this is probably fairly representative of the population distribution.
dave
dave
Attachments
FE103As in BK101s -- for anyone tempted to build these, you might as well just put them in a sealed box (except these are cooler looking) -- that said, these speakers in my lab are one of the most useful speakers i've ever owned... the jacks on the front are very useful.
dave
dave
Attachments
and here they are in the Fostex FE103 recommended horn... these need work. They have a "closed-in" character in the mid-range that makes them hard to listen too. 1st thing we are going to try is apacer plate on the front to make the compression chamber larger (Chris B-Horns with FE108ES developed a similar charachter when he decreased the compresion chamber). The Tim Forman-style ML-Voigts with 40-1197s easily out perform them. (the vintage iMac is intended to become a digital music server, and the black box has the Peerless 8s -- the ones with the really low Fs).
dave
dave
Attachments
So when we say that the B-Horns are the best we've tried, we have tried a few others.
Once Fuzzmeasure gets T/S capability (or the weather gets better) i will get a sample set of parameters and i have a bipole 103 horn bouncing around in my head that will get out sometime.
An early concept sketch attached -- it has evolved from this sketch.
dave
Once Fuzzmeasure gets T/S capability (or the weather gets better) i will get a sample set of parameters and i have a bipole 103 horn bouncing around in my head that will get out sometime.
An early concept sketch attached -- it has evolved from this sketch.
dave
Attachments
planet10 said:
A bit off topic, but I was thinking of doing the same with mine. I wish I was proficient enough to work out a way to strip it down, get rid of the screen and fit all the remaining circuitry, HD and CD/DVD player into a 'hi-fi box' with an lcd display and proper audio in/out connections
backing up to the ribs
Dave,
I see the ribs in the cone in the larger driver, but I don't see anything in the pix of mine either in the cone or the dustcap. I assume, if they're there, that they stiffen the cone with little weight penalty, which would make the wave launch more uniform. What about the resulting sound makes them "special"?
Geez, it's nice to have such a wealth of information and experience at hand as I dip my big toe in the FR pond!
Yes, Sound Hounds is a great hifi shop. Terry and crew are a class act and know whereof they speak. Careful, though. The E kits will spoil ya! ;-)
Dave,
I see the ribs in the cone in the larger driver, but I don't see anything in the pix of mine either in the cone or the dustcap. I assume, if they're there, that they stiffen the cone with little weight penalty, which would make the wave launch more uniform. What about the resulting sound makes them "special"?
Geez, it's nice to have such a wealth of information and experience at hand as I dip my big toe in the FR pond!
Yes, Sound Hounds is a great hifi shop. Terry and crew are a class act and know whereof they speak. Careful, though. The E kits will spoil ya! ;-)
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