MartinLogan Motion XT C100 vs Polk Reserve R400
The MartinLogan Motion XT C100 is more sensitive (93 dB vs 89 dB), so it plays louder per watt and plays lower (42 Hz vs 48 Hz). The Polk Reserve R400 is an easier load for a receiver (8 Ω vs 5 Ω) and costs less ($699 vs $1,600).
What each one works with
Checked against every product in our catalogue by the same engine as the compatibility checker.
| Motion XT C100 | Reserve R400 | |
|---|---|---|
| Receivers and amps that drive it | 28 of 29, 14 after a setting change | 29 of 29 |
Specs side by side
Values that differ are bold. A dash means that model doesn't publish the spec.
| Motion XT C100 | Reserve R400 | |
|---|---|---|
| Impedance | 5 Ω | 8 Ω |
| Sensitivity | 93 dB | 89 dB (2.83 V, 1 m) |
| Low end | 42 Hz | 48 Hz |
| Drivers | 1 × 32 mm, 2 × 165 mm | 1 × 25 mm, 2 × 165 mm |
| Size | 24×8×14 in | 24×8×14 in |
| Recommended amplifier power | 20–300 W | 40–200 W |
| Weight | 15.4 kg (34 lb) | 14.9 kg (32.8 lb) |
| MSRP | $1,600 each (MSRP, September 2026) | $699 each (MSRP, September 2026) |
Every spec and pairing: MartinLogan Motion XT C100, Polk Reserve R400.
Try either one in your own room.
Draw your room in 3D, place it with the rest of your system, and see every connection checked. Designing is free.
References
- MartinLogan Motion XT C100: Spec sheet, martinlogan.com, retrieved September 15, 2026
- MartinLogan Motion XT C100: Retailer listing, audioadvice.com, retrieved September 15, 2026
- Polk Reserve R400: Spec sheet, polkaudio.com, retrieved September 15, 2026
- Polk Reserve R400: Owner's manual, polkaudio.com, retrieved September 15, 2026
- Polk Reserve R400: Manufacturer product page, polkaudio.com, retrieved September 15, 2026
Brand names are trademarks of their owners. Not affiliated with or endorsed by any manufacturer. 3D models are our approximations. Prices are manufacturer list prices (MSRP) as of the month shown. How we earn from buy links: affiliate disclosure.