The woofer is generally the largest driver in the system, which covers the bass and mid-range frequency.

The B+ used a 12” woofer with a paper cone and an AlNiCo magnet. In the 1990’s and 2000’s, we sold a small number of replacement woofers using a black poly cone and a large ferrite magnet. Both woofers used a biodegradable foam surround which needs to be replaced every 30 years or so.

With the return of your original B+ woofer, we offer an upgrade replacement woofer, which uses a paper cone and a neodymium magnet. The upgrade replacement woofer offers superior bass transient response, as well as increased power handling. As an added bonus, the surround technology on the upgrade replacement woofer will not require periodic replacement like the original did.

Included in the price of the upgrade replacement woofer is the pre-installed SubBass Activator circuit. This unique device is hand-wired to extend the reproducible low frequency range of your speakers and protect them from subsonic transients.

This upgrade is recommended in pairs, for optimum stereo reproduction. Price per each.

The high tweeter is generally the smallest driver in the system which covers the highest frequencies.

The B+ used a one-inch polycarbonate dome tweeter. It offered the greatest high frequency extension that was available at the time, with relatively wide dispersion. This tweeter requires no periodic maintenance, but can fail from being overdriven.

A damaged tweeter may either produce an audibly distorted “scratchy” sound, or may produce no sound at all, making the speaker sound very dull. In either case, a damaged tweeter should be replaced with a new tweeter.

As an upgrade replacement tweeter, we offer a three-quarter inch cloth dome tweeter. It produces slightly smoother treble response, with wider dispersion than the original.

We have no more of the original tweeter face plates leftover from production of the B. If you so choose, you may send in your original tweeter in advance, so that we can fit your new tweeter to your original face plate. Please let us know when you place your order if you would like this additional service. If you do not return your original tweeter, you will receive your upgrade replacement tweeter mounted on a wooden face plate.

Recommended in pairs for optimum stereo reproduction. Price per each.

The grill is the cloth and frame used to cosmetically conceal the drivers without affecting the sound.

The B+ used a grill with brown fabric covering a jointed particleboard frame, ornamented with the original die-cast Ohm logo badge in the upper left corner.

In almost all cases, the grill was nailed in place at the factory. We recommend carefully removing the grill and replacing the nails with hook and loop fasteners. (The nails should tap out very easily with a hammer from the back of the grill.)

Sometimes, the grills can become damaged. Grills with a buckling or broken frame, or with holes or runs in the fabric, should be replaced with a new grill.

Our new replacement grill for the B+ features black fabric covering a single piece plywood frame. It comes with hook and loop fasteners pre-installed on the back, and a new Ohm logo badge installed on the front. (Sorry, no more of the original die-cast logo badges!)

Recommended in pairs for cosmetic matching. Price per each.

The crossover is the electrical circuit that protects the tweeters from the low frequency energy that is reproduced by the main drivers. This can only fail, in rare instances, from overdriving the speakers.

The B+ crossover offered a single adjustment for the tweeter, by way of a knob on the back of the speaker. Of all the parts in the B+ crossover, this is the part most prone to failure. Still, it should be replaced only if it’s been shown to be damaged.

In our extensive experience with these crossovers, the electrolytic capacitors in this circuit do not typically “drift” or decay with age. They should be replaced only if they’ve been shown to be damaged.

When you send in your original B+ crossover, Ohm will repair or replace it, at our discretion. We strongly recommend sending in both crossovers, even if only one needs service, so that we can match the repaired “bad” crossover to the “good” crossover.

These crossovers are both glued and stapled in place, so please take your time and work carefully if you need to pull one out of its cabinet.

Price per each.

The low tweeter is generally the midsize driver in the system which covers the upper mid-range and low treble.

The B+ used a phenolic ring tweeter to augment the output of the same high tweeter used in the B. The effect was a substantial increase in power handling, which drastically reduced failures in the updated model.

This tweeter requires no periodic maintenance, but can fail from being overdriven. A damaged tweeter may either produce an audibly distorted “scratchy” sound, or may produce no sound at all, making the speaker sound very dull. In either case, a damaged tweeter should be replaced with a new tweeter.

As a replacement tweeter, we offer an enhanced version of the original phenolic ring tweeter, featuring a Penta-Vented^TM cone and Ferrofluid liquid cooled voice coil. Both of these innovations increase linearity of the tweeter’s response, and improve power handling. The replacement tweeter also comes with a protective mesh screen covering the front, and a hollow state limiter wired in line and mounted on the back of the tweeter.

Price per each.