The Motion Foundation B1 is the standmount that brings MartinLogan's folded tweeter into a price most systems can reach. That transducer is the reason to look at this speaker rather than a conventional dome design.
Folded Motion works by pleating a thin diaphragm and squeezing air out from between the folds instead of pushing it forward. Moving mass drops sharply, and treble arrives with a speed that domes struggle to match at any price.
An aluminium mid-bass cone carries everything below the crossover, and the handover sits high, which keeps voices on a single driver through most of their range instead of splitting them.
Sensitivity is generous and the load is mild, so a modest integrated amplifier drives it properly. It suits a smaller room, or the rear channels of a system whose front speakers already share this tweeter.
MartinLogan Motion Foundation B1 official product page
| ITEM | DESCRIPTION |
|---|---|
| Folded Motion tweeter | A pleated diaphragm with far less moving mass than a dome. |
| Aluminium mid-bass cone | A stiff cone carrying the whole vocal band below the crossover. |
| High crossover point | Voices stay on one driver instead of being split across two. |
| Generous sensitivity | Drives properly from a modest integrated amplifier. |
| Range tweeter match | Shares its treble character with the floorstanders above it. |
| DETAIL | VALUE |
|---|---|
| Driver complement | 1 x 0.94" x 1" (2.4 x 2.5cm) Gen2 Folded Motion Tweeter S, 1 x 5.5" (14cm) aluminium cone mid-bass driver |
| Frequency response | 48 Hz - 23 kHz ± 3 dB |
| Sensitivity | 89 dB |
| Nominal impedance | 5 ohms |
| Recommended amplifier power | 15 - 100 watts |
| Crossover frequency | 3,400 Hz (2-way) |
| Dimensions | 34.6cm x 18.4cm x 24.05cm (13-11/16" x 7-1/4" x 9-1/2") |
| Weight | 5.2 kg each |
| ITEM | QUANTITY |
|---|---|
| Motion Foundation B1 loudspeaker | Pair |
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