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History
The Frugel-Horn
existence directly follows from answering the question "DIY design similar to
hornshoppe?" -- a thread that was on a previous incarnation of the Decware Forum
(closed down now). (the person who asked the question is now enjoying his own
set of diy Frugel-Horns with modified FE126e)
Initially we derived a modified Buschorn MK1, widely regarded as being a reference
for compact corner-horns, by modifying it to accept larger drive units. The design
was simulated (assuming free-space positioning) and the results compared to the
measurements taken by Stereophile of the excellent Hornshoppe
Horn which rumour has came from a similar genesis. Free space positioning removes
room influences from the response, and ensures that only the horn's performance is
analysed. An impedance curve tells you a lot about a box, and in the case of a horn
the peaks & nulls are a reflection of the horn's expansion and foldings. The
respective responses, simulated and measured, matched closely. This assured us that
we had a horn with bass alignment very close to the speaker in the thread title,
and something we could build on. A sim won't tell you about all the little tweaks
& tricks to make a good sounding speaker a great one, but, if one adds in years
of experience, it does give high confidence that at least it is close. (plans for
this modded B-Horn are in one of the appendices of the Frugel-Horn plan document). |
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The
initial conceptual 3D line render with an FE108eSigma
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Red (FR) &
black (Imp) are the mod B-Horn sim, purple (FR) & green (Imp) the Stereophile
measures -- clik for larger graph
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We built 2 of these so
that we could get a handle on different drivers -- primarily the FE126 & FE108eS.
We were happy with the 1st prototypes for the FE108; the ones with FE126 need some
CC tuning. Detailing the CC and changing to modified FE126e has us preferring the
126 over-all. It is really astounding what these little babies can do (and we weren't
done yet).
While developing these plans we saw places where some changes could be made to make
the design more elegant and more versatile for DIY use. This primarily involved rerouting
the 1st folds to move the voids to where they could be used as additional compression
chamber volume (or as many have done, opened up to punctuate that these are folded
horns). The width was also increased slightly givng an 8% larger mouth and a slightly
less radical mouth aspect-ratio. |
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insides of Hornshoppe
Horn
-- this linked picture from the positive 6moons.com review and has also been
posted by Ed Schilling on public forums a number of times -- it was the inspiration
for the modified B-Horn test mules
This design was built
and immediately some changes were made to simplify the horn path to make it easier
to build (alpha 1.3.0). These plans were released. Some early adopters built this
horn and the general consensus was that we had something worth pursuing further
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Meanwhile Ron Clarke was
doing his magic to the horn mouth. He derived the optimum curved mouth exit and the
deflector. The curved mouth helps compensate for its high aspect ratio (ideally a
horn has a square or circular mouth) and the deflector minimizes reflections back
into the mouth and ~doubles the controlled mouth flare. We had already incorporated
supraBaffles similar to those on his Austins. These 3 "add-ons" to the
alpha 1.3.0 gave 5 possible levels of build. Renderings were done to illustrate the
possibilities.
The full-up build of the horn (alpha 1.4.0 Level 3) was built and got its 1st public
exposure at the 3rd annual Vancouver Island diyFest where acceptance was overwhelmingly
favorable. Based on this, the build was elevated to Version 1 status (and alpha 1.3.0
builds became Version 1 Level 0 builds).
A comprehensive set of plans was completed & released. A number of horns have
been built from these and feedback is coming in -- generally very positive. Minor
updates have been released. |
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alpha
1.2.1b with supraBaffle & modified FE126e
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Form follows function
and comparisons with the horn that inspired the Frugel-Horn are inevitable. No-one
has done a direct comparision. Technically the Frugel-Horn -- in level 1 & higher
builds -- has some technical advantages, but as we all know the devil is in the details
& execution will always play a role.
With size & format more or less fixed the Frugel-Horn will not pretend to offer
things that really are the realm of larger horns. If you can live with something
larger and more obtrusive there are other options such as Ron Clarke's A126 (the
current reference for our evaluation), the Dalek Horn, and any number of others --
many now residing here on this site. |
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