This 2 way bass reflex speaker contains an Air Motion Transformer Eton ER4 and a Eton 8-472/32 HEX.
Like already determined by Klang+Ton assessing the Duetta the ER4 requires a small volume.
An excerpt of the review by Hobby HiFi: "The E-Motion is a loudspeaker for all types of music and for highest quality demands. With the exception of extreme volumes this speaker is delivering the goods. This considered the E-Motion is certainly not expensive. Only thanks to the EURO one doesn't have to spend an mount with five digits for a similar finished loudspeaker."
Due to the low tuning (the bass extends to 20 Hz) the E-Motion is not suited for extreme volumes. Otherwise, the relatively small diaphragm's linear excursion would be too big.
For highest volumes we recommend a Duetta or Duetta Top with an adequate subwoofer, like a large Sub-Kult or an Alcone Sub 12 or Sub 22/400.
price for the E-Motion kit without cabinet per unit: EUR 639,00 Hint: without Bawotumex the kit is 64,80 EUR cheaper
or with high-end crossover: -with Mundorf copper foil coil 3.9 mH/cfc12 (0.39 Ohm) -with Mundorf copper foil coil 0.68 mH/cfc16 (0.26 Ohm) -with the lowest loss capacitor we know of (ahead of ER4): Mundorf MCAP-Supreme 15uF / 800 V
Price for the E-Motion/high-end kit without cabinet per unit: EUR 780,00
Home Hobby HiFi Overview Floorstanding Loudspeakers