Ohm B

The Ohm B was the very first speaker shipped by Ohm in 1971. It was a very large bookshelf (the exact size of the then popular AR-3a) speaker. It was a 2-way system with a 12” woofer and 1” dome tweeter. 2-way systems with large woofers were later popularized by the Advent Loudspeaker.

Purchase OptionsPriceOrder

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.

$345 2

The 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 one inch cloth dome tweeter. It produces slightly smoother treble response, with much higher output capability than the original. It is therefor far less prone to failure.

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.

Crossover service

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.

$179 3
(1) With the return of the original part for recycling within 60 days.
(2) With the return of the original part for recycling before the shipment of the new part.
(3) Recycled repaired and tested.
(4) Per pair.
(5) Special shipping rate applies.
Ohm B Specifications
Production Period
early 1970s
Nationally Advertised Price
$500 per pair
Amplifiers Recommended
25 - 100W
Impedance (typical)
Frequency Response
32 - 20,000 Hz (+/-3dB)
Sensitivity @2.8 Volts
86 dB
Recommended Room Sizes
1600 - 4800 cu.ft.
  • The Ohm B was the very first speaker shipped by Ohm in 1971. It was a very large bookshelf (the exact size of the then popular AR-3a) speaker. It was a 2-way system with a 12” woofer and 1” dome tweeter. 2-way systems with large woofers were later popularized by the Advent Loudspeaker.

  • The upgrade option available for the OHM B is a new pair of poly-cone woofers, which includes a SubBass Activator, which eliminates the drive below the speaker's natural response to reduce distortion and clean up the deep bass. This allows for lower distortion, higher output and deeper bass, plus uses a self-resetting protection circuit.

    Note: Most Ohm upgrades require no specialized knowledge and are easily completed completed by any person. It takes less time to install your own upgrade than it does to package and return ship your speakers to the factory, therefore, we recommend you save time and money by doing this yourself. We ship the upgrade to your door with clear, easy instructions. If for any reason you prefer to have the factory complete your upgrade installation, we will be happy to do this for free, however, you will be responsible for shipping and handling costs each way.

  • Ohm allows up to $500 for the return of a complete pair of undamaged Ohm B's toward 25% of the purchase price of new Ohm speakers.

Contact Us

Ohm Acoustics Corp.
28 Tiffany Place, Unit 1L
Brooklyn, NY 11231 USA
Toll free: 800-783-1553
Phone: 718-422-1111
Service: 718-422-1111
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