Guesswork & Woodwork
Introduction : The Fortress Of Solitude
The classic profile of a high-end speaker system is at heart a multi-driver,
complex-crossover, low-efficiency brick-- nestled protectively in blankets of damping and reinforced
silence. To reconcile the complex behaviors of the differing drivers and to minimize resonance and reflection, the cabinet
is usually constructed of of massively thick, super strong materials. The system is assembled with all possible
build overkill, and lots of internal layering, all in an effort to be a neutral source of sound, free of cabinet influences
The sleeping, blanketed brick is thus constrained in every direction,
acoustically isolated, mechanically cushioned, and electrically locked into submission, and consequently, must
be awakened with a strong kick from powerful amplification. So a few hundred watts of feedback-controlled
power amplifier may not even be enough. It may take totals of a thousand watts of bi- or tri-amplification, to
awaken some of the sleepier overgrown bricks.
Anyone with trained or experienced ears can tell you that virtually any music
playback construction has its own sound -- whether a messy euphonic color-generator, or an overdamped lockdown from which
lifelike sounds can never bloom.
It would be false to claim that my approach here to speaker systems is 1oo%
a refutation of the 'locked-down-brick' school of high end loudspeaker. Because the truth is that this level of
build overkill and coffin-like cabinet-making is very much beyond my skills and resources anyway. Because half the approach
here is that of necessity, there will be no huge table-saws, cnc-cutting, routering, vacuum-clamping stations or
ovenbaked finishes; there will be no eight-foot sheets of materials, no inch-and-a-half thicknesses of anything.
Because I have no experience with those procedures, no real competence with those materials, and just don't have
any of that on hand.
But there should be no mistake-- fifty percent of the approach is still is
the idea that amplifiers with full harmonic qualities but lower wattages should be able to drive reasonably efficient
speaker systems, in well-thought-out cabinetry that is light and rigid. Like a cello's sound box, strutted and
braced with numerous site-specific ribs and crosspieces each designed to their own purpose, each reinforcing the overall
integrity of the whole.
The Dull Glow Of Limited Success
Since I knew that these wouldn't be the last enclosures for my new/old Tannoy
dual concentrics, I had the idea that the first efforts might just be the right time to try something adventurous. I
had the idea that lightweight construction-- but with fairly sophisticated bracing -- might be an approach to good sound that
wouldn't deaden the harmonic bloom, or discourage lively pacing & poise in the time domain. Perhaps I could sidestep
the curse of the hibernating bricks.
As a first look into the world of the Tannoy renaissance, I had read the indispensible
TannoyMania by Harvey Rosenberg. My thought was that soon enough, my Tannoys would evolve into a
Transmission Line effort, and eventually, a Back-loaded Horn enclosure, but like any completely new project with its own learning
curve it might be best to start with something simpler. So why not first try some simple boxes with walls intact, as
with 'infinite baffle' types, and live with those for awhile. Not too further down the road, 'bass reflex' ported boxes
could be the next effort.
Well on the way by now, I ran into an article on the Hans Hilberink Tannoy
Monitor Gold©®™ site, that mentioned the phrase 'torsion box' ... an interesting
approach that accomplishes a large, braced enclosure that isn't life-threateningly overweight. But this version
apparently required a serious wood shop. So I promptly looked elsewhere, in that such cabinet work was
beyond my resources here. My "resources" in the woodworking department, it should be mentioned, are best described
as budging the needle just beyond zero. I knew for a fact, for example, that building any rectilinear box of 12" speaker
scale with perpendicular walls and accurate joinery was pretty much beyond my range of capability. But that really couldn't
be the end of the story.
Because the storyline I'm sticking with is that you should extend all of
your budget into the part of the system you can't manufacture yourself, ie the raw speaker drivers -- and moving
along in time you'll be able to build cabinets of increasing sophistication and/ or eventually settle on original Tannoy or
custom carpentry. This should ensure an ongoing baseline of playback integrity, with each new level enlarging
the frame, validating that those expensive drivers are expanding their capabilities.
So, I'd have to do a bit of range-finding, taking various stabs at under-
and over-building some small-box woodworking, like transformer or powersupply boxes and chassis projects, and I did just
The dull glow of limited success illuminated a path, a way in through the kitchen
door, just for me. If I couldn't reliably make razor-straight cuts or mitered edges or ninety-degree corners,
I'd just have to order some in from the outside world.
Since purchasing custom-cut panels of virtually any woods or plys was an expensive
invitation to fouling the joinery (I knew without trying), I hit on the hollywooden idea of using stand-ins
for the real thing. All that was required, really, were inexpensive, uniform, and relatively square wooden forms
around which I could construct my cabinetry.
Before I go on, it should be apparent that I had absolutely no qualm or uncertainty
that my Tannoys might sound their best in a matched set of Westminster Royals -- or Canterburys -- or Churchills or Glenairs,
for that matter. It's just that the raw drivers are so ridiculously expensive these days, and the first couple of cabinet
renditions to house them would have to be conscious of my budget. As in: no budget at all for cabinets, due to
the budget having been spent entirely on the perfect vintage speaker drivers.
A long road to get to this, but that's the way some of this do-it-yourself
audio goes; a couple of eventual days of execution, preceded by months of figuring out your own peculiar strategy.
And that road came to a halt outside my local wine-merchant's premises. Not the shop, exactly, which was also a
help in its own way, but outside, at the Dumpster.
Where I found stacked, higgledy-piggledy, a dozen or so average
wine crates. It was the holidays, and they were moving a lot of product. The crates are made of low-grade
boxwood but displayed exactly what I didn't have -- reasonably square ninety-degree corners, clean edges, and a workable,
building-block size & scale appropriate to speaker cabs. These could be tacked together to obtain the shape,
used to build the cabinet forms around, and then knocked apart from within and discarded.
As I thought further about the idea, I noted that these stand-ins were themselves
capable of transporting twelve bottles each, somewhere between thirty and forty pounds in total, across international distances,
and had proven themselves over hundreds of years and still counting. Although they were in many respects contrary to
loudspeaker objectives (resonant and flexy, non-rigid) they might endure the trial run to provide more than just
temporary forms, and could be used as skeletal frames, once glued, strutted, braced and then mass-relieved via cutouts,
to create an internal bone-structure on which to build outwards ...
So at least there was something of a roadmap, an itinerary of maybe-yes
maybe-no experiments to make, none of which involved completely closing the door on future versions, and none of which
required much in the way of expenditure.
We were on our way toward a landing. We know you have many choices of
speaker enclosure strategies, and we congratulate you on choosing the cheapest seats in the house.
Next, let's revisit that Torsion Box idea ....