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Pair of black rectangular indoor/outdoor speakers with silver woofers, mylar midrange and tweeter, U‑brackets attached

Acoustic Audio

Acoustic Audio 251B indoor outdoor 3-way speakers 400 W black pair

SKU CH-MQP3-FG802

Weatherproof indoor/outdoor pair delivers 3-way sound with 4" woofers, 2" midranges and .50" tweeters at 99 dB sensitivity and 100 W RMS each

  • Driver size4 in Dome Woofer 0.5 in Mylar Tweeter 2 in Mylar Midrange
  • Frequency range37 Hz
  • Rated impedance8 Ohms
  • Audio sensitivity99 dB
  • Product typeIndoor/Outdoor Speakers
  • Product colorBlack
  • Weather-resistant cabinets handle rain and snow
  • 3-way driver array covers 37 Hz to 20 kHz
  • 99 dB sensitivity produces loud output from modest amps
  • 100 W RMS per speaker sustains clean playback
  • Included U-brackets simplify wall or ceiling mounting

Indoor/Outdoor 3-Way Pair

The Acoustic Audio 251B is a passive two-speaker set built for indoor and outdoor installation. Each cabinet houses a 4-inch poly woofer, a 2-inch mylar midrange and a 0.50-inch mylar tweeter in a sealed black ABS enclosure. Spring-loaded raw-wire terminals accept standard speaker cable. Mounting brackets and hardware are included for wall or ceiling placement.

Sustained Output and Coverage

Rated at 100 watts RMS and 200 watts peak per speaker, the pair handles continuous programme material without compression when driven by an amplifier delivering between 20 and 300 watts per channel. The 99 dB sensitivity at 8 ohms yields high output levels from modest power, while the 37 Hz low-frequency extension supports full-range reproduction down to the lowest octaves. Weatherproof cabinets resist rain, snow, sun and ice for year-round exposure.

Upgrade From Basic Stereo Pairs

This set replaces single-driver patio speakers or entry-level bookshelf models that lack dedicated midrange clarity and deep bass authority. The three-way topology separates vocal and instrument detail from low-frequency impact, making the jump worthwhile for whole-house audio, home-theatre surrounds or commercial background systems where consistent coverage matters. Buyers needing wireless streaming or powered convenience should look elsewhere.

How it compares

Measured against everything we stock in Home Speakers & Subwoofers, at today’s prices. Recalculated every night.

Price $34.99
Cheaper than about 93% of the 1,147 comparable items (median $133.99).

Specifications

Product
Brand nameAcoustic Audio
Model name251B
Product typeIndoor/Outdoor Speakers
Product colorBlack
Audio & video
Driver size4 in Dome Woofer 0.5 in Mylar Tweeter 2 in Mylar Midrange
Frequency range37 Hz
Rated impedance8 Ohms
Audio sensitivity99 dB

Questions about this item

How much heat or noise does the 251B produce when running all day?

These are passive speakers with no internal amplifier, so they generate no heat or fan noise regardless of how long they play.

What must I already own to drive the 251B speakers?

You need an amplifier or receiver with raw speaker-wire outputs capable of 20 to 300 watts per channel at 8 ohms, plus CL3 or raw speaker cable.

Will the 251B work alongside my older 8-ohm bookshelf speakers in a multi-room setup?

Yes, the 251B presents an 8-ohm nominal load and 99 dB sensitivity, so it matches the impedance and plays at a similar volume level to other 8-ohm speakers driven by the same amplifier.

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