Frugel-Horn Mk3

[wagtail]

hi, i am awaiting delivery of alpair 7's for pencil 7 build but it was the frugel-horn which fired my enthusiasm for a diy build so i think i will have a go at the mk3, where can i get the dimensions please?

[Scottmoose]

V. little time as I've three lectures to write today, but FWIW, some general notes:

-Simplicity was a primary object of this box; it also needed to be compact (while taking feedback from the 1st FH into consideration), and forgiving of different drivers (within reason), largely to help encourage people new to the hobby.
-If a pipe has positive expansion, viz. expands toward the terminus, then by definition it's a horn. FH3 is as much a horn as FH1; albeit a very different variation thereof this time around.
-No, it can't be unfolded. Sorry Jeff, but glad you like the look of it. The dimensions of the cabinet are functional parts of the design (to answer your other question, those boxes in the background are a prototype pair of my Maeshowe cabinets that Dave & Chris are playing with).
-Back-horns don't actually possess compression chambers per se (save in the case of reactance-annulled designs). FH3 began as a single-tapped hypex horn with the expansion briefly choked at one point to provide a degree of low-pass filter effect (per Olson & a little pre T/S BR design). Fo however is actually little affected.

[Bigun]

Looks very nice.

will there be one of those large baffle thingies to go on the front as an upgrade ?

[edjosh23]

Dave,
You said in the other thread you had trouble tearing yourself away from the A7. Is there a driver you like most in this design?

Josh

[chrisb]

Originally Posted by Bigun

Looks very nice.

will there be one of those large baffle thingies to go on the front as an upgrade ?

what a supra idea!

There was not quite enough time to execute that for this particular demonstration, (the 4 pairs for the driver swapping on Maeshowe took priority), and we also wanted to test a range of (4 different) drivers in this pair to confirm versatility. The (latest version) FE126E was quite impressive indeed.




Interested builders might like to know that due to the curved side panels of this latest version, when using BB plywood a little creativity is required to yield all the parts from a single 5x5 sheet and retain vertical grain direction on the most visibly exposed parts ( sides/front/ top), but then grain pattern/matching is a particular hobby horse of mine.


In the case of our first build, accumulated offcuts from other projects were used, so the following cut plan was after the fact. For the side panels I made an MDF template, rough cut with jig saw, then finished with router and pattern bit.

a 4x8 sheet would have lots of room to spare

[chrisb]

Originally Posted by SemperFi

We all need a pair at times. Though sometimes they can grow a bit large and we need to get back to earth. The way it is to be a man.

and a large pair can certainly get in the way in the shop - fortunately after 37yrs of marital bliss, that's no longer an issue for me

[chrisb]

Originally Posted by Phil Townsend

How did you like the Mark Audio Drivers in this box?

There was too little listening time at the tail end of the 3 days of craziness that is the "festivus",* so our initial impressions need to be tempered, but I personally preferred the FE126En in this enclosure

In other designs, such as Maeshowe, or the appropriately dimensioned "Ken", the Alpair7 is certainly an eye-opener

http://www.diyaudio.com/forums/clubs...ml#post2284036



*only a brief overview of the organized chaos of such events:

http://www.diyaudio.com/forums/clubs...ml#post2278948

[planet10]

FH3 as we got to is a big vent mass loaded tapped horn (hypex executed with 2 conical sections)

Plans are ready to be released to a few brave beta testers (actually anyone that wants). Damping for different drivers, alternate construction methods wrt the "point", suprabaffles, deflectors all need exploration. Measures in room. Documents -- a single sheet so far -- need fleshing out.

The Mark Audio drivers sounded good. The A7 was my favorite in them. Some may find that the bass may need a bit of reduction (more damping, pulled more out into the room).

dave

[LCole]

I was curious as to whether the 'choke' in the hypex horn could be raised to the point that it would be removed. I understand the choke acts essentially as a low pass filter but would increasing the line length (thus the height of the cabinet) do the same thing?

I'm terrible at modeling these things and I'm sort of a noob when it comes to the design process so normally I'd just go build the thing (modified) and report back my findings if they were particularly favorable. Too many irons in the fire at the moment.

You'll have to forgive all my queries and speculation- I'm not trying to take away from what I see as a physically marvelous looking speaker. It has, however, sparked my imagination enough to build a variant of it, a little taller perhaps, but similar in other respects. I figured that you, as its initial designer , could verify whether my vision, variant, spawn or whatever is worth pursuing: a folded tapped hypex horn, very similar in design but less of (or none) a choke.

I would be interested in trying to build what you've got there, as is though, maybe to be used as a reference for further design.

No response to my querie regarding something similar but for the BOFU's?

[type]

Originally Posted by planet10

FH3 as we got to is a big vent mass loaded tapped horn.

Plans are ready to be released to a few brave beta testers (actually anyone that wants). Damping for different drivers, alternate construction methods wrt the "point", suprabaffles, deflectors all need exploration. Measures in room. Documents -- a single sheet so far -- need fleshing out.


dave

How would they be without the curved back? How do I get the plans?