This design really has evolved well, has there been any work/progress on a scaled up version for 6.5" drivers?Thanks Chris
I'm looking at a 6.5" driver. Early sim's show a falling response parallel to the infinite baffle profile and ~4 dB above.
No sooner do you boil it down when I come along and spin it..
let me second guess Dave and Scott on this - extrapolating experience with a range of Fostex and Mark Audio drivers in the FH3, I'd be inclined towards something like the FE166E / FF165K, etc for a larger F-Horn
I personally found the Mark Audio drivers an bit bass heavy in the couple of horn type enclosures in which I've heard them so far, and definitely prefer them in Pensil and of Mar-Ken series.
Just finished a slightly modified FH3 version for FE126en.
Instead of the little widget at the bottom where the internal and back pieces meet, I made both the internal and back pieces longer so they sat where the widget would have, 1 1/2" from the bottom, and then I used a 3/8" round over bit and rounded the outsides of each piece over. Seemed simpler than attaching a piece of 1/2" round to it.
I also rounded over the top of the interior panel.
I then felted the entire interior chamber with 2mm felt. I tripled it up at the spots that is says to apply 1/2" felt.
The cabinets are also 1/8" narrower internally. I decided to route the side panels so that the interior and exterior panels would lock in. 1/16" router grooves. I then used an expanding adhesive silicon in the grooves and screwed everything together. Wanted the seal of the silicon but it doesn't have much structural strength.
Listening to them right now through my Bottlehead SEX. Once the drivers break in I will experiment with some polyfill and take some measurements. Gotta say I am impressed though. These things sound great.
Instead of the little widget at the bottom where the internal and back pieces meet, I made both the internal and back pieces longer so they sat where the widget would have, 1 1/2" from the bottom, and then I used a 3/8" round over bit and rounded the outsides of each piece over. Seemed simpler than attaching a piece of 1/2" round to it.
I also rounded over the top of the interior panel.
I then felted the entire interior chamber with 2mm felt. I tripled it up at the spots that is says to apply 1/2" felt.
The cabinets are also 1/8" narrower internally. I decided to route the side panels so that the interior and exterior panels would lock in. 1/16" router grooves. I then used an expanding adhesive silicon in the grooves and screwed everything together. Wanted the seal of the silicon but it doesn't have much structural strength.
Listening to them right now through my Bottlehead SEX. Once the drivers break in I will experiment with some polyfill and take some measurements. Gotta say I am impressed though. These things sound great.
My primary interest is the A12 i plan on ordering after tax season, but i'll be happy if my ole Fostex FE166ES-R are good with them.
RE flat-paks... keep an eye on the planet10-hifi forum, Chris & i are just now detailing the 1st run. There will be a pre-order with a discounted price.
As to the efficiency difference... what some users are getting away with with the MA drivers i have found quite surprising. One client (Doorman) went from Fonken167 to CHR-Ken (a loss of 10 dB), and is still happy with his 3.5 w amp. YMMV
In my room, i like to have ~10-20w on tap for the smaller MA.
dave
As to the efficiency difference... what some users are getting away with with the MA drivers i have found quite surprising. One client (Doorman) went from Fonken167 to CHR-Ken (a loss of 10 dB), and is still happy with his 3.5 w amp. YMMV
In my room, i like to have ~10-20w on tap for the smaller MA.
dave
FWIW, I'd stick with the Fostex at those power levels, but then I prefer it overall in this enclosure, regardless of available power.
IMHO, the Mark Audio drivers come into their own with about 5watts of tube power, and deliver their most refined performance in enclosures other than horn - in which I find them a bit too fat in the bottom end for my own taste.
of course YMMV
I'm so infatuated with the idea that I'm going that route anyway - Mark Audio drivers in horns - but can I ask you to describe the fatness a little? Is it just ... too many decibels in the low end? Or is it lumpy, bumpy, or resonating? In other words, is the tubbiness frequency-domain, or is the time domain affected?
(I realize that I'm asking for a subjective description - one would be most well appreciated.)
I found the fatness kinda pleasant -- more than i'd consider balanced and micely rounded. And that out a ways from the wall. It was actually expected as the FH3 were damped for the FE126, more was expected to be needed with the higher Q drivers, but needing the A7 in the Pensils, never got the opportunity to play with that. FE127eN are mounted up now. Just have to wire em up to the terminals. They should similarily need more damping to reign in the LF.
dave
dave
FWIW, I found the batting calculated and weighed out by Dave for A7 in Pensils a bit over-damped, and removed approx 1/3 of the volume. Thank goodness I made the back panel removable - otherwise controlled access to the lower portion of tower would be "virtually" impossible - even without cross-linked bracing.
So for folks contemplating the FH with whichever driver, I'd strongly suggest the initial assembly should allow for removal of one side to permit adjustment of damping levels. Tailor the optimum only after drivers are well broken in, and with speaker sited in its final room location, and I wouldn't judge with "free" side clamped on - the mass and tension of clamps will affect the enclosure's resonance characteristics. Rather, use #6 wood screws for temporary attachment and weatherstripping tape for seal.
BTW, a bit off topic for a FH thread, but the Pensil7 is another very nice performer by Scott. Damned simple build compared to the "--Ken" series, and makes for a killer small room (320 sq ft) HT speaker.
(PS -I'll sort you that tenner out later.