Two types of add-ons are immune to the antipathy caused by such
'evils' as graphic equalizers or click suppressors. Most diehards
will forgive/approve of dedicated extras of any type because they
can be regarded as extensions of the basic components rather than
as sonic intruders. The other 'okay' black box is the more
sophisticated, usually external crossover system which allows the
user to bi-amplify his or her speakers. As the latter most often
tends to be the former, you can assume that most hi-fi casualties
approve of dedicated crossover systems with even greater vigour
than they'd show for 'universal' crossovers.

After a flurry of activity a decade ago, when 'active' and
'bi-amping' were hot buzzwords, the hi-fi community reverted to
the simpler, less costly path of conventional or single-amplifier
operation, partly because of a growth in popularity for
bi-wiring. Virtually a halfway house between the amp-per-driver
luxury of bi-amplification and the mundane operation of
conventional wiring, bi-wiring swept the industry in the best
trickle-down manner; it's now found on quite inexpensive two-way
box speakers. Among the champions of bi-wiring was Apogee, whose
complex full-range ribbon systems benefitted immeasurably from
the technique. It also served as a respectable compromise for
Apogee owners who couldn't afford a second high-current amplifier
and outboard crossover for true bi-amplification.

Although a number of companies, like Audio Research and Krell,
produce active outboard crossovers of a universal nature, the
design team at Apogee accepted the premise that the best
crossover is dedicated to the speaker with which it will be used.
Even the easy-to-access specifications of crossover points and
slopes will not guarantee a perfect match, and simply setting a
universal active crossover network to suit a speaker with, for
example, a 6dB per octave slope at 2kHz won't necessarily result
in the ideal pairing. Apogee felt that good as some of the
currently available crossovers may be, they cannot optimize a
system unless they've been designed specifically for that system.

In addition to offering attenuation of up to 6dB in 1dB steps for
the woofer and the mid/tweeter, the company's DAX (Dedicated
Active Crossover) allows the user to adjust the balance between
woofer and mid/tweeter in 0.2dB steps and to adjust the 'rake
angle', a sort of 'hinge' in the tonal balance which tips the
midrange above 1kHz in +/-0.5dB steps at around 5kHz. The DAX
also provides facilities to match the crossover to the amplifiers
for input impedance loading, gain characteristics (for using
different amplifiers top and bottom) and for using single-ended
or balanced operation. Because of the way the various DAX
controls interact, the unit can vary the group delay, important
when sculpturing the gain vs. phase relationship -- and one aspect
of DAX-equipped Apogees is near-perfect phase response.

By addressing both the requirements of only three specific
loudspeakers (you order your DAX preset for Caliper Signature,
Duetta Signature or Diva) and allowing for matching to any
amplifier, the DAX provides what amounts to total control for
biamplifying their speakers. This in turn enables the listener to
tailor the sound for both the electronics and the listening
environment, beyond the obvious tweaking one can perform by
speaker positioning, cable selection and wholesale changes of
hardware. In the case of the Diva, the DAX takes over from the
passive box with its four toggles for boost or attenuation at
four frequencies, but the switch for the tweeter on the passive
box remains operable. This is because the DAX is a two-way
crossover while the Diva is a three-way system. The DAX sees the
tweeter and midrange as one section; the toggle on the passive
box allows the user to cut or boost the tweeter by 2dB in
addition to shaping the operation via the DAX.

The Diva's passive box therefore takes on a different role and no
less than three-and-a-half pages of the owner's manual deal with
converting it for use between the DAX and the Diva. You don't
have to worry about this because your dealer will undertake the
conversion, which involves replacement parts supplied with the
DAX and the bypassing of much of the passive enclosure's innards;
remember, the bulk of its functions are now controlled by the
DAX. Still, if you enjoy spending a couple of hours inside a nest
of wires, be my guest. With the Duetta, instructions are also
supplied for user conversion, but the Caliper must be modified by
the dealer.

Speaker conversion aside, the actual installation is a doddle if
you've ordered your DAX correctly. I asked for a version set up
for using single-ended amplifiers, the same top and bottom (two
Aragon 4004s), but even if I decide to change, the manual covers
the range of adjustments which are accessed via dip switches
inside the DAX. If you want to mix amplifiers, you'll have to
know the gain characteristics, while choosing between balanced
and single-ended operation merely involves flicking the toggles
to the left or the right. As for input impedance matching, the
DAX arrives in standard form with 80k ohms preset for
single-ended operation or 10k ohms for balanced. Four other
values are available for either mode. (See specifications below.)

The DAX slips into the system just where you'd expect it to,
between the preamplifier and the power amps. I ran the Audio
Research SP-9 into the DAX and the DAX into the Aragons via
Master Link cables, with Lieder speaker leads connecting the
amplifiers to the modified passive boxes. The gold RCA sockets on
the back of the DAX are clearly marked, the rear split into left
and right halves, so feeding the four signals from the DAX is no
more confusing than wiring up a conventional stereo set-up.

The DAX itself is one of the most attractive pieces of high-tech
hardware I've ever seen. Apogee has come up with a satin black
finish which screams of luxury, visual confirmation that this is
one high-priced goodie. The fascia is split into three sections,
the left and right thirds containing four rotary controls each
while the centre consists of what might be the most useful
display yet to grace a hi-fi component. Left-to-right, the groups
of knobs include woofer attenuation, woofer-mid/tweeter balance,
mid/tweeter attenuation and rake, with separate knobs for each
channel. The Hewlett-Packard display, glowing a fetching green
(which must be this year's colour as the Aragons, the SP-9 and
the CAL Tempest II power supply also glow green), gives you
digital read-outs of every setting, again separated into left and
right. With this bank of controls and the digital confirmation,
it's possible to set up the system for sonically asymmetric rooms
using test tone generators and spectrum analyzers, or you can (as
you'll see) use it to compensate for recordings with any previous
settings being easy to note. Power to the DAX is via an outboard
unit a third the size of the DAX. This houses the on/off switch
and a front-panel LED; it connects to the DAX with a locking
cannon plug.

Apogee presupposes that its customers know what they want to
hear, so instructions for setting the controls amount to little
more than doing it by ear. I did manage to find out how Apogee's
Jason Bloom approaches the problem each time he sets up a DAX and
his advice means less to-ing and fro-ing. Future DAX owners, take
note:

1) Adjust the mid/tweeter attenuator, which is another way of
asking yourself, 'Do I need to cut the upper frequencies?' (In
the unlikely event that you need to boost those frequencies,
there's still the toggle on the passive box.)

2) Adjust the balance between the woofer and the mid/tweeter.
This maneuver attenuates either portion in 0.2dB steps. You
won't believe it until you hear it, but this operation is audible
enough to change the character of the system from
forward-sounding to muted, despite the seemingly limited
operating range. And only a deaf person or a reactionary/liar
would deny the audibility of a change of even one step.

3) Adjust rake angle. By tipping the response up or down in 0.5dB
steps, it's possible to compensate for brightness or dullness
without any loss of information or frequency extension. I've a
feeling that owners of Quad electronics will find this not a
little familiar.

4) Adjust woofer attenuation. This is especially useful for those
who would have Apogees in small rooms. (No, there's no woofer
boost because it's unlikely that anyone would ever need it. And
if they do, they can always go back to steps 2 and 3.)

But here's where it gets bizarre. Word had reached me that the
DAX, even with everything at '0', improved the performance of the
Divas beyond the gains that you'd expect from mere biamping. That
struck me as odd until I accepted that the DAX -- two amplifiers
instead of one notwithstanding -- is a vastly more sophisticated
crossover than the passive box supplied as standard. And not only
does it do a better job of signal splitting, the DAX also
optimizes the interface between amplifier and speaker, allowing
the amplifiers to see a trouble-free resistive load instead of
the complex impedance of passive-crossover'd Divas. But the
reason it bothered me is because I preferred the DAX at '0' on
four out of five recordings. Like most of you, I refuse to
believe my good fortune when I find that my system and/or room
needs no help.

And so it came time to play...

Here's where I usually go crazy and tax Roget to the limits. It's
also the point where I regret that specialist magazines haven't
taken note of what's going with graphic novels, because I sure
could do with some help from the likes of Alan Moore. Picture a
frame-by-frame EC-type cartoon of KK, saliva dripping down his
stubble'd chin, eyes wide and nearly touching his Zeiss lenses.
The hair -- what's left of it -- is up on end and a balloon from
KK's mouth reads 'YAAARGH!' or some such exclamation. Yeah, the
DAX is like that. If this wasn't a family magazine, I could
really go to town, but it is so I can't and besides, Editor
Harris prefers to have contributors of sluggish pulse.

Well, THAT'S TOO DAMNED BAD!!! The DAX is simply the niftiest
little marvel I've ever used, a jolt of steroids which boosted a
system that I thought could only be improved by tiny increments.
It is to the Diva what spinach is to Popeye. And it's Kryptonite
to everyone else.

Listen: When I set up the DAX, I was also playing host to
somebody who has no reasons for wishing success on this product.
I won't embarrass him by revealing his name; all I'll say is that
he's from the competition. Anyway, we put on some serious music
-- Billy Cotton's Wakey Wakey Show and George Melly on C5 Records
-- and he just looked at me, uttering a British expletive which
rhymes with 'buckshee' and grinning from ear to ear. We fiddled
with the knobs, cranked up the volume, dug out some naff mono CDs
of ultra-thin-sounding British pop from the 1960s. We rocked. And
we heard the Kinks' 'Waterloo Sunset' like it's never been heard
before.

What the DAX does is turn the Diva from a simply magnificent
speaker system into some kind of limitless performer which
virtually defies criticism. Auditioning the system with music of
utter familiarity, I was embarrassed at how much more the Diva
could offer. And the areas which benefitted most were areas which
I didn't think need any improvement.

The most blatant manifestation of the DAX is the way it allows
the Diva to present deep bass notes. I admit that, on occasion,
the Diva can sound a bit overwhelming, with bass which thunders
and roars. Suitably DAX'd, the Diva's extension remains constant
but the bottom octaves acquire a sensation of greater control.
That's with everything set at '0'. You want to tighten things up
even more or recess the midband for reggae or House at the max, a
touch of the controls will shift the balance to suit your tastes.

Equally chilling are the gains in soundstage creation, image
placement and specificity. The Diva, sans DAX, is simply one of
the best imagemakers I've used; the DAX opens the sound and
removes and last vestiges of texture to the silences between
instruments and players. What the controls do is allow you to
dial in the most realistic stage depth in a manner not unlike
that of the control unit for the Infinity IRS Betas.

And the more you learn about the controls and their capabilities,
the more they take on the nature of a focussing ring on a camera
lens. What they do is nudge the sound one way or the other in
tiny, repeatable steps and without any sense of added noise.

But here's where I find myself at cross purposes with the whole
concept of active crossovers. Until the DAX arrived, I thought of
trick crossovers as a way of optimising the speaker, something to
set once and leave alone. Because I reviewed the system with such
a wide range of material, from LP transfers of 78s from 1926 to
too-hot-to-handle club mixes to purists' delights, I found myself
using the DAX to compensate for the recordings rather than the
hardware or the room.

The DAX is ghostly quiet and absolutely precise in everything it
does. Although it doesn't have an instant bypass mode to allow
the user to compare settings in A/B fashion, the digital readout
means that you can tweak something and return to a previous
setting for comparison purposes with absolute accuracy. Starting
each LP or CD with the readings at '0', I then altered the sound
as per the above-mentioned steps. After a few hours, I was able
to ignore the four-step procedure and go straight to, say,
woofer-mid/tweeter balance or rake if I knew that the other
controls didn't need adjusting. Judicious use would suppress
ludicrous sibilance (some Juice Newton and Poco recordings) or
restore weight to thin recordings (most Beat Boom UK pop).

What I don't want to do is give the impression that the DAX works
like a dream-world equalizer or even like the rather splendid
Cello Palette. The effects are most assuredly audible, even those
0.2dB changes, but the adjustments to the sound are too subtle
and too precise to suggest any gross tampering. What it becomes,
then, for an Apogee owner is the ultimate surgical instrument.

Which leads me to the two questions I asked Apogee. The first is
whether or not they'd be offering it with remote control, because
it sure would be handy to be able to adjust it from the listening
position. They have thought about it, but the price -- already
breathtaking at #4500 -- would have to go even higher and they're
not certain the demand is enough to warrant the option; call it a
'maybe'. The other question is whether or not Apogee would
consider making a version for use with other makes of speaker,
but -- in line with their arguments about the need for absolute
dedication ot each model -- this would be too impractical and
probably too much hassle in simple political terms.

So that means that this joyous device is only available to Apogee
owners. All I can say to those who possess Duettas, Calipers or
Divas is that you must forget about everything else in your
upgrade progression and put the DAX at the top of the list. And
here's a justification if you need it:

In the year I've been using the Divas, I've tried them with
single amplifiers (in bi-wired mode) running to over #10,000 per
pair. The DAX offers such a transformation with even the
affordable Aragons that two Aragons plus DAX at a grand total of
#8100 is preferable to any other non-DAX combo I can name. What I
have yet to experience are the gains of going to balanced
operation, and I still want to try the mix'n'match flexibility,
especially as the DAX renders the system 3dB more efficient and
therefore even safer with big valve amplifiers. As it stands, the
DAX is nothing less than the most exciting development yet for
Apogee owners, a device so clever that I wish other manufacturers
would offer similar units for their bi-ampable speakers. #4.5k
for a black box? Yes. And it's worth ever single penny.