Frugel-Horn Mk3

I've bought myself a pair of Markaudio CHP-70's from Blue Planet Acoustic for the equivalent of only 72 USD including shipping. These are the European version with the black frame and yes, that price is for a pair, as they're on sale.

I have very little experience with DIY loudspeakers. I made a pair of sealed enclosures with Philips full-rangers as a teenager, so these would be the first loudspeakers I've built in over thirty years :)

Anyway, I'm thinking of putting these into Frugel-Horns Mk3 and I've read the Frugel-Horn threads with interest, but haven't seen any mention of a baffle step correction/compensation circuit. Is it necessary or will the horn loading be enough?

If not, can I simply use a BSC calculator to determine the circuit or is there a more arcane method?

Regards,

MAW61

try without BSC - it's easy enough to add later if you like; I would suggest you consider the supra-baffle - it certainly made quite an improvement in previous BLH projects I played with ( FHI / Clark A126)
 
I searched but can't find any reference to supra-baffle for 2 drivers aligned vertically. If 2 frugals are stacked (top one inverted) you could use one big supra-baffle to bind them. Actually after testing with a mock-up the final product would be just one big cabinet with shared tops. Anyone know of an image or drawing of a baffle like this?
 
I searched but can't find any reference to supra-baffle for 2 drivers aligned vertically. If 2 frugals are stacked (top one inverted) you could use one big supra-baffle to bind them. Actually after testing with a mock-up the final product would be just one big cabinet with shared tops. Anyone know of an image or drawing of a baffle like this?


I haven't stacked or siamesed a pair of FH, but by the time you conjoined a pair vertically, you'd be close to the Valiant / Maeshowe dual rear mouth, seen here from an event this August

185126d1282600610-7th-annual-vancouver-island-diyfest-2010-fr-fri-saburo.jpg



the axis dimensions of the ellipse were 267x386 (~10.5"x 15 1/4")

frankly, I don't think this design needs 2 drivers per side to fill a room, even one as spacious as Dave's

every couple of years I have to revise the statement "most impressive enclosure in which I've yet heard the Fostex FE126E" - and for now, this is it:

http://www.wodendesign.com/Valiant.html
 
Last edited:
Thanks Chris - I'm sure you're right about not needing 2 per side but since I'll be getting a quad of EL70s this is just something I want to try along with some bipole designs. I guess I just need to stretch that baffle out and see what happens.

Have you tried mets for bipoles - or are you "the guy", and want to try bipoles with something else? My favorite dual driver design for the MA drivers so far is the funky little micro-tower - tons of WAF, and sounds great.
 
Really haven't tried anything as I haven't ordered the drivers yet. Well I am building some B20 half changs for another room but don't have the el70s. I saw where you referred to the castles as your 'daily drivers' and I want to try those. WAF not an issues in this room. Basically since I can't make up my mind I want to cobble together different boxes with osb and see what I prefer. Mets are on the list as are Maeshowes. We'll see how it goes - sounds good on paper though.
 
Really haven't tried anything as I haven't ordered the drivers yet. Well I am building some B20 half changs for another room but don't have the el70s. I saw where you referred to the castles as your 'daily drivers' and I want to try those. WAF not an issues in this room. Basically since I can't make up my mind I want to cobble together different boxes with osb and see what I prefer. Mets are on the list as are Maeshowes. We'll see how it goes - sounds good on paper though.


time to ride my current hobby horse - if you're playing around with cheap prototypes, take a look at:

http://homepage.mac.com/tlinespeakers/FAL/downloads/microTower-maps-150909.pdf

if you forego the bracing and fancy finishing, etc., you could blast a pair together in a couple of hours.
 
you'd be close to the Valiant / Maeshowe dual rear mouth, seen here from an event this August
every couple of years I have to revise the statement "most impressive enclosure in which I've yet heard the Fostex FE126E" - and for now, this is it:
Woden Design | Valiant
Chris, they're described as suitable for modest spaces to modest to large for the Valiant, i'm not clear on the size of the room range. Can you tell me what distance do they need to be from side and particularly the rear wall given the rear firing double mouth? Also about how far of a listening position distance from the driver?
 
Chris, they're described as suitable for modest spaces to modest to large for the Valiant, i'm not clear on the size of the room range. Can you tell me what distance do they need to be from side and particularly the rear wall given the rear firing double mouth? Also about how far of a listening position distance from the driver?


I've heard them in 3 separate locations with the FE126E, and 2 with the EL70:

my place:

1) FE126 - 450+ sq ft open plan upstairs, carpeted, lots of upholstered furniture, spaced 3 feet from corners of 15ft wall (~ 9ft separation), 1ft from back wall. about 30` toe-in - sweet spot seat approx 10ft - source iTunes/MacBookPro/ Airplay > AEX toslink> Citypulse DAC > EL84 triode P/P . I haven tried to break any windows in this room since the Adire Shiva sub about 10yrs ago, my max SPL is well under 95dB, but that's still enough to fill the room adequately for me

2) FE126 / EL70 320 sqft "den" - the TV system - approx same placement / listening as above - Motorola HD cable box> Rotel RB850

Dave's place (back in August, hard to remember which of 4 pairs of drivers we didn't listen to ):

I can never remember the total cubic volume, but with steeply sloped ceiling and open floor plan (must be at least 500 sq ft?), it's plenty big enough to reveal shortcomings in low frequency energy and dispersion patterns.

Due to general clutter, speakers are generally 3-4 from back wall, and at least as far from closest corner to the right - and at least 15 ft on the left side. You'd think a single pair of 4" drivers would have trouble in this space - not necessarily so. Listening position is approx 10-12?

With their diffuse LF energy dispersion pattern, the tall double rear mouthed horns are IMO very well suited to larger spaces, and have less integration issues than front mouth variants of approx same dimensions.
 
That ''general clutter'' as Chris puts it, sure makes for a decent listening space with lots of possibilities for experimentation, and I think all the stuff goes a long way acoustically to make a nice sounding room as a side benefit..

I remember my first visit there and enjoying some good sounds, and liking when we listened to the old 103's and whatever artist was playing, not to leave out all the other good sounds too ..

You do realize that if you were to push up daisies tomorrow, you'd be leaving the better half (Ruth) with a whole lotta stuff to go through ;)

You have a good room to really give OB, IB, or whatever a good go and hear, lots of possibilities as you already know.. Gotta love the privacy and acreage that close to the city too, nice locale!
 
With their diffuse LF energy dispersion pattern, the tall double rear mouthed horns are IMO very well suited to larger spaces, and have less integration issues than front mouth variants of approx same dimensions.
Would the diffuse LF dispersion/less integration issues allow for both the Valiant and Victor to be used in smaller more modest room's with 7' or 8' between drivers and from the listening position?
 
Would the diffuse LF dispersion/less integration issues allow for both the Valiant and Victor to be used in smaller more modest room's with 7' or 8' between drivers and from the listening position?


From what I've heard - yes - if the room is less than 300sqft, I'd personally be quite happy with the performance of the smaller of the two named designs - Valiant /FE126 or Maeshowe / Alpair 7.
 
Another pair built. These ones live in Port Douglas, Far North Queensland, Australia. I've been following this and other threads on the FHmkIIIs for a couple of months. I would have posted earlier but every time a had a question, the answer was already in the thread!

Anyway, Big thanks to Dave, Chris and Scott, and everyone who asked the questions and got the answers I needed.

I used 18mm ply and loaded them with CHR-70s. Finished with figured cherry veneer they sound and look ace!

Murray.
 
Be easy enough to try. Given that the FH Mk3 works with the Mark Audios there is a good chance that it will be fine. At least 1 pr of successful Mk1s were made with FE127 and Mk3 is more versatile.

Poke me if i don't get back... i've got to pull the A7 out of our prototypes to put in the Pensils, i have a set of FE127eN waiting for a box.

dave


Hey Dave,
Did you ever manage to get the set of FE127eN into this design?
Byron