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Two round plastic speakers in a pair, 4021 model

Ruth's sister

Ruth's sister 4021 4 Ω 3 W speaker pair

SKU CH-7QG9-B7KRD

Two-piece 4 Ω 3 W full-range speaker set with 99-10000 kHz response and 89 dB sensitivity for notebook DIY audio

  • Stereo sound from a matched pair of 4021 drivers
  • Full-range 99-10000 kHz response covers the audible band
  • 4 Ω 3 W rating suits low-power notebook amplifiers
  • 89 dB sensitivity delivers clear output from modest power
  • Round plastic cabinets with paper diaphragms for lightweight DIY installs

Pair of 4021 4 Ω full-range drivers

Two 4021 moving-coil loudspeakers are supplied in a single pack, each rated at 4 ohms impedance and 3 watts continuous power. The round coaxial-composite cones use paper diaphragms and are housed in plastic cabinets. They are intended for home hi-fi use or as wired DIY replacements in notebook computers and similar electronic equipment.

Sustained output within the 3 W rating

Rated input power is below 25 watts, so the drivers operate comfortably at their nominal 3 W level without thermal compression. The full-range frequency characteristic covers 99 Hz to 10 kHz with omnidirectional directivity, maintaining consistent dispersion during extended listening sessions. Sensitivity of 89 dB ensures adequate volume from modest amplifier power.

4 Ω impedance matches compatible amplifiers

The 4 ohm nominal impedance is the critical specification for amplifier pairing; the connected amplifier must be stable into a 4 Ω load to deliver the rated 3 W without distortion or protection shutdown. Channels are listed as 5 (4.1), indicating multi-channel system integration is possible when the amplifier supports that configuration.

Highlights

  • Stereo sound from a matched pair of 4021 drivers
  • Full-range 99-10000 kHz response covers the audible band
  • 4 Ω 3 W rating suits low-power notebook amplifiers
  • 89 dB sensitivity delivers clear output from modest power
  • Round plastic cabinets with paper diaphragms for lightweight DIY installs

Specifications

No published specifications for this item yet.

Questions about this item

How much power do the 4021 speakers draw during all-day use?

The input power is under 25 W and the rated output is 3 W, so continuous draw stays very low.

What must I already have to connect these 4 Ω drivers?

You need an amplifier or device with Euroblock terminals that can drive a 4 Ω load at 3 W per channel.

Will the 89 dB sensitivity match my older amp without volume issues?

At 89 dB sensitivity the pair works well with typical vintage or modern amps; no extra gain staging is required.

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