Volume 7 Number 5
Hands-On Review - Acme Low B-1 Series II

by Michael O'Brien

Like all Acme speakers, the full-range B-1 is designed to reproduce the 31 Hz B string, and to do this the B-1 has one custom designed 10-inch Eminence woofer, which is the same woofer used in the B-1's bigger brothers: the B-2 and B-4. This woofer is capable of longer excursion (the speaker's path of travel from front to back) than other similarly sized woofers, which is what allows the Acme bass speakers to speak so low. The B-1 also shares the same five-inch cone midrange and one-inch dome tweeter as its siblings. The B-1 is 15.75 inches (40.0cm) high, 15.75 inches (40.0cm) wide, and 13.5 inches (34.3cm) deep, and it weighs a back-pleasing 31 pounds (14.1kg). The B-1's strap handle is placed to be perfectly balanced with the speaker's magnet, so carrying the B-1 is nearly effortless; further, this handle does not diminish the cabinet's structural integrity as larger handles can. The B-1 is available in four- and eight-ohm configurations, is covered with heavy-duty carpeting, has vinyl and padded covers optionally available, and can be factory-fitted with a receptacle for "common" tripod stands. The rear-panel speaker connections include 1/4" banana-type, and Speakon. The B-1 has the same midrange and tweeter attenuators as all Acme speakers. The B-1's port is side mounted. This unique port placement is unaffected by any directional activity as port direction [placement] is utterly unimportant as long as the port isn't covered. The B-1's frequency response is rated as 41 Hz to 22 kHz, +/-3 dB (-6 dB at 31 Hz).

The B-1 I is built like a tiny wooden tank and seems nearly as bullet proof with its black metal edges, grill screen and heavy-plastic interlocking corners. Knocking on any cabinet surface yields no stray resonances, which if present can detract from the sound quality of any cabinet, especially bass cabinets. And Acme's documentation is more like an engineering white paper than a manual; it's as thorough as any musical-instrument documentation you can name (if not more so). The list price for the B-1 is $360.00 (US), shipping included, and Acme offers a two-week trial policy.

Acme sent us two four-ohm B-1s. We used them with an Aguilar DB-659 tube preamp and a Crest Vs-450 (225W/ch. into four ohms), a Walter Woods' integrated amp (1000 watts, bridged-mono into four ohms), and an Acoustic Image (A.I.) CLARUS integrated amp (200W into four ohms; 300W into two ohms). We also used one B-1 as an extension cabinet with an A.I. CONTRA combo amp (same power specs as the CLARUS). In addition, we used the B-1s at a Jazz gig (in a medium-sized club) with a stork 1964 Precision, a German-made double bass with a K&K pickup, the M. CLARUS, and the Walter Woods (in bridged mono with one four-ohm B-1).

Other instruments used for this review, but not at the Jazz gig, included Sadowsky four and five string basses, a Rick Turner four-string fretless Renaissance, and Elrick four, five, and six-string basses. We also compared the overall sound of two B-1s versus one B-2.

In our reference tests and comparisons, and with every bass, two B-1s sounded uncannily like one B-2, although there was a perceptibly greater fullness to the B-2s lowest frequencies, especially with the five- and six-string basses (as admittedly subjective as this might seem). But overall, the now legendary Acme low-end extension and heft were there in spades; the overall frequency response was rich, full smooth, and "hi-fi" without a trace of the "peakiness" or selective frequency drop-out found in other speakers. In addition, the B-1 sounded great with the A.I. CONTRA, adding a great deal of fullness to the CONTRA's sound; the B-1 would make a fine extension cabinet for just about any combo amp.

Like its larger relatives, the B-1 is no less power hungry: Acme rates the B-1 at 175 watts RMS continuous (150 watts sine wave at 30.87 Hz) and rates its sensitivity at 90 dB (1 watt at 1 meter). But as we quickly discovered. the B-1 can successfully and safely be used with amplifiers capable of much larger power outputs. But first, here are some words of advice: use low EQ sparingly with the B-1.

Because the B-1 is a full-range high-fidelity speaker, it provides full sound quality without the need for gross EQ adjustment, which can needlessly rob precious amplifier power and can result in excessive and distortion-inducing woofer excursion. With every amp we used we found that flat EQ settings always seemed to yield the most pleasing and effortless sound from the B-1s. Also, ensure your amplifier has good damping capability which is the amp's ability to control speaker excursion at low frequencies and is expressed by a ratio between the amp's output impedance and the speaker's impedance (called the "damping factor" [DF]). Amps with the best DF are typically solid state amps because transistors have an inherently low output impedance. Conversely, tube amps have notoriously high output impedances and, therefore, a low DF In other words, and considering the stated premise of using the right tool, you'll probably have better success using the B-1s with a high-quality solid state amp than you will with a tube amp, especially a low-wattage tube amp, regardless of quality or "tweak" appeal. But of course the final discriminators are your ears: if something sounds good to them, then it works.

Live, the two B-1s sounded very good with the CLARUS (seeing a 2-ohm load). This rig effortlessly reproduced the double bass's subtle tones; the rich sound of the bass's wood was everywhere in the room. Each note seemed to be the same volume, and the low-end extension was simply sensational. The B-1s projected all the double bass's frequencies clear to the rear of the room. We then tried one B-1 with the mono bridged Walter Woods amp; there was no discernible diminishment of low-end extension or projection. The double bass's complex woody tones were every bit as present everywhere in the room. The single B-1 had no problem standing up to the drums, guitar, and trumpet, and this was in a very loud room with very hard floor, wall, and ceiling surfaces. The sound of the Precision through both rigs was equally impressive, although the extra heft provided by the Walter Woods' 1000 watts was no doubt a function of this amp's approximately 6 dB of additional headroom versus the CLARUS. Clearly, a direct comparison of the 300-watt CLARUS to the Walter Woods would be unfair, especially considering that the CLARUS's primary design goal is as an acoustic-instrument amp. But in this specific acoustic context, the CLARUS was an excellent march with the two B-1s and the Upright.

In conclusion, the B-1 is the right tool for you if you have a high-quality solid state amp, your jobs put you in small- to medium-sized rooms, and you want to reproduce the fullest sound of your bass instrument to its greatest potential. As for flexibility, and depending on the type and variety of jobs you play, you might consider buying two or even four eight-ohm B-1s. Think about it: this way you could bring one or two B-1s for the small jobs and two or four for the big jobs. This would work perfectly if A) your monaural amp is capable of two-ohm loads or B) your stereo amp is capable of four-ohm loads, both channels driven. (Plus, the B-1's banana connections provide added cabling and impedance-matching flexibility.)