(The following text is excerpted from the new Series II "Owner's Guide," and describes the improvements over the previously existing Acme Low B systems.)
Introducing 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, viola, 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fall far from the tree, and in this case they are right- our new tweeter of choice is the model from Audax which superseded our beloved shallow horn.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 it’s 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.