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The Series II Models
Since the introduction of the original Acme Low B-2 in December 1993, and
the Low B-4 in September 1994, the speakers have remained unchanged until
now, with the exception of a rust-proof powder coating on the front grilles.
The original period of development of these two models was long and painstaking,
and I believed at the time of their introduction that nothing could be done
to improve them.
In the ensuing years, with the distribution of the speakers all over the
United States and six continents (no customers in Antarctica yet), we have
had the opportunity to receive comments and feedback from a very diverse
group of individuals. Most of the suggestions had been anticipated during
the design process, and weren't particularly helpful. Some advice has
been valuable, however, and was filed away until such a time as a number
of small improvements could be incorporated into a different enough speaker
to justify a new designation: 'Series II'.
The incorporation of these changes has been concurrent with the development
of our new Low B-1 1x10"; model, which is being introduced as part of
the 'Series II' line, even though no previous 1x10" model existed.
One other reason these several small changes have been 'saved up'
for their simultaneous introduction into a design which I believed to be
essentially perfect years ago is that the manufacturer of our little tweeter,
Audax, actually discontinued this marvel of high output and cost effectiveness
in mid 1996, shortly before Scott Malandrone, of Bass Player
magazine discovered our products and introduced them to the bass playing
world in the November 1996 issue.
After the review in BP was published, we scrambled for tweeters, and bought
every one we could find in the United States and Canada. A sizable pile of
tweeters it was. But not any more. We've used them up.
Interestingly, after examining a great many tweeters from a great many
manufacturers since then, we were reaching a point of total frustration when,
voila, in mid 1998 we were able to examine samples of the latest high-sensitivity
models from, you guessed it, Audax.
They say the fruit doesn't fall far from the tree, and in this case
they are right - our new tweeter of choice is the model from Audax which
superseded our beloved shallow horn. The new model is a slightly deeper horn.
It has a larger voice coil, a rare-earth neodymium magnet, handles more power,
and in fact, exhibits slightly less coloration, and better projection than
our original tweeter, which was quite good. Like its predecessor, it
is a marvel of high output in a tiny package. Unfortunately, it's a
little more expensive, but it sounds better too, so that's OK.
The incorporation of this new tweeter into an existing design is what made
development of the 1x10" model take so long. It required an enormous
computer model to 'exactly' duplicate the response of the original
system through passive equalization. Extensive passive EQ is difficult, because
it has a way of making the impedance drop too low for most amplifiers to
handle. The job was devilishly difficult, but in the end was quite successful.
What are the other changes which distinguish the Low B Series II from the
original? Several things.
The distinctive metal edges which gave our speakers such a conspicuous appearance
were considered important in the early days of the company because, frankly,
we were trying to be noticed. This isn't a concern any more. In fact,
we have heard of TV producers who actually balk at the idea of having such
a glaring piece on their soundstage.
After we upgraded the bare metal screens to a powder-coated finished version,
in 1997, as a rust preventative, it became clear that eventually the metal
edges would benefit from a similar treatment. The Series II models have a
new charcoal black powder-coated steel edge protector. Better.
The original Low B crossovers had a design drawback which has been corrected
in the new models. The attenuators, which control the output of the midrange
and tweeter were unprotected. In cases of stupidity or accident (about 3%-4%)
it was possible to burn one or both attenuators out. It had never occurred
to me that this would be a problem, and even though it has been an unusual
occurrence, it has been annoying and frustrating for manufacturer and customer
alike.
Not any more, however. We found a way to add a component to the crossover
which actually introduces itself gradually into the circuit as the attenuation
is increased, and it is now all but impossible to damage the attenuators.
The trade-off is that the midrange and tweeter output can only be reduced
by 20 dB, which is equal to 99% power reduction, instead of being totally
shut-off.
Another change which has been made to the crossover is that instead of being
supplied with twin 1/4" input jacks, as before, the Low B now comes
equipped with a single 1/4" jack, banana jacks, and a Speakon connector.
Both banana and Speakon provide greater electrical integrity than the more
common 1/4" phone-type connector, and the industry seems to be aware
of this, so I've decided to jump on this bandwagon.
Handles. I've been internationally condemned and universally chastised
for my choice of small, recessed handles for the Low B systems, particularly
in the case of the large B-4 unit. I know when I'm licked. I admit that
the handles I've used on the B-4 are essentially useless, other than
providing internal support for the ports, and I've caved in to popular
demand- the Low B-4 Series II now has larger, heavier, and more useful handles.
It's the best example of this type of handle I've been able to
find, and they aren't cheap. The B-2 still has the small recessed handle,
because it hasn't been such a problem with this smaller speaker.
The Low B-1 is equipped with a Fender-type strap handle. It is a great handle
in terms of preserving cabinet integrity, and serves the second function
of helping avoid obstruction of the speaker's side-mounted port.
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