What the maker puts in writing
- “Each OoO speaker holds two 3-inch square frame woofers in a ported enclosure, achieving usable bass extension down to 60Hz”
- “The tweeter is based on Micca’s popular 0.75-inch silk dome design, using a high efficiency neodymium magnet and small diameter bezel for tight driver spacing”
- “A 6dB/Octave low-pass circuit is used on the woofers while a 12dB/Octave high-pass circuit with level matching is used on the tweeter”
- “Its slim shape can be used horizontally as a center channel speaker, vertically as bookshelf speakers, or use with optional wall mounting brackets as surround sound speakers”
- “The compact Micca OoO speaker sounds much larger than it looks”
Thirty hertz from doubling the cones
Micca sells both of these on this shelf, and the comparison is as clean as it gets:
COVO-S, $59.99 — one 3-inch woofer — “usable bass extension down to 90Hz”
OoO, $129.99 — two 3-inch woofers — “usable bass extension down to 60Hz”
Same brand, same driver diameter, same ported principle. Thirty hertz of difference — close to half an octave.
Because bass is a question of air moved. Doubling the number of cones doubles the radiating area, and each cone then travels a shorter distance for the same output: less distortion, and a lower limit before the driver runs out of excursion.
The other route to the same place is one larger cone. Dayton’s B65 at $79.98 uses a single 6.5-inch driver — roughly four and a half times the area of a 3-inch — for fifty dollars less.
Square frames, which is why it can be this slim
Two 3-inch square frame woofers.
A conventional driver has a round frame, so the cabinet must be wider than the cone by the full width of the mounting flange all the way round.
A square frame puts the fixing holes in the corners, letting the cone come much closer to the cabinet edge. More radiating area for the same baffle width.
On a speaker 3.90 in (99 mm) deep that is the whole point. And the tweeter follows the same logic: “a small diameter bezel for tight driver spacing”, which closes the gap between drivers and keeps their outputs better aligned.
It is a center channel lying down
Can be used horizontally as a center channel speaker, vertically as bookshelf speakers.
Woofer — tweeter — woofer. Laid on its side, that is exactly the standard center-channel layout, and it exists because a center speaker has to fit the narrow space under a television: the drivers spread sideways rather than stacking.
The practical benefit of a symmetric array is that it behaves the same whichever way up it goes. A conventional speaker with the woofer under the tweeter, laid on its side, radiates unevenly across the room — the two drivers’ outputs now cancel sideways rather than vertically, so one seat on the sofa hears a dip the next one does not.
If you are assembling a system from this shelf, one OoO as the center and a pair as surrounds is a coherent plan.
And the crossover is deliberately asymmetric
A 6dB/Octave low-pass circuit is used on the woofers while a 12dB/Octave high-pass circuit with level matching is used on the tweeter.
That is the most considered crossover statement on the shelf, and the asymmetry is the point.
The woofers get a gentle filter — one component, minimal phase disruption, letting them run up naturally.
The tweeter gets a steeper one, because a 0.75-inch dome has almost no excursion available: feed it bass and it hits its limit, raising distortion across the whole treble band. Twelve decibels per octave keeps that out.
And level matching addresses the arithmetic of this design: two woofers produce more output than one for the same input, so the tweeter needs lifting to match them or the speaker would sound bass-heavy.
For comparison, Micca’s MB42 uses 6 dB/octave throughout and the MB42X G2 uses 12 — and that single difference is the forty dollars between them.
What is not published
No impedance, no sensitivity, no power handling — where both MB42 models publish all three (4–8 ohms, 85 and 86 dB, 75 and 80 W).
Sensitivity is the omission that matters, because it decides what amplifier you need: every 3 dB is a doubling of required power. Only Dayton’s B40 publishes a recommended range (10–50 W).
No frequency ceiling, only the 60 Hz floor. And the floor is stated as “usable”, which is an honest hedge — unlike a bare range with no tolerance. The only true tolerance on this shelf is the SMSL’s ±3 dB.
Optional wall brackets, where the Edifier has one built in and both Daytons have keyhole points.
5,561 g and 175 × 279 × 99 mm are published.
Prices quoted in this text were read on October 4, 2026. The live price is at the top of the page.
