Specifications:
Frequency range: 38Hz~20kHz
Nominal impedance: 8?
Sensitivity: 97dB
Drive units: 300mm paper cone Woofer, cloth surround, aluminum diecast basket
510mm Dome titan.compressive alt driver, rear-radiant ,Neodymium magnet
Horn: Normal wood or piano wood,90 degree level extension.,
Cabinet: MDF plate, normal wood surface, phase inverter sonic structure
Crossover frequency:1000Hz
Dimensions: 950*430*500(H*W*D)
Net weight: 35kg

While Opera audio has remained loyal to the tube amplifier, analog sources and high-efficiency loudspeakers, the  listener experiences very natural sound.

Fifteen-inch horn loudspeakers remind one of the period before transistors ruled and tube amplifiers was the way to drive high-efficiency loudspeakers. With an output of 98dB at 1 meter from a single watt, M15's are the sensitive type. A humble 300B-based 8-watt amplifier has enough oomph to party.

The M15 is a two-way speaker equipped with a massive 15-inch/ 38cm paper-cone woofer with a cloth surround  . It uses a large wooden horn tweeter crossed over at 1000Hz to a 15" cone woofer. A 3" dome compression driver at the rear drives the pressed-wood horn that sits on a castanet woofer module, both with matching fine-furniture-grade walnut veneers. Similar as Altec but better than their metal horn design , the horn is not physically attached to the woofer module.

This construction design improves the direction characteristics and the response off axis.

The modified tweeters bring better frequency response. Both linearity and stability are improved by using a specialized cone imported from the UK . The voice coils have a hgh effiency and power handling.

Even though construction design is capable of excellent integration, a crossover remains necessary to define the transition between both drivers. For the M12 and M15 line, opera audio relies on the simplest possible network design. A pure copper gilded 75uf circuit board and SCR capacitor and an oversized coil are all that separates the big unit from the tweeter.

With the above improvement, the high frequency of the M15II and M12II is more extended, the mid frequency is fuller and the low frequency is deeper. At the same time, It has a better analytic and more detailed sound.

Specifications:

Frequency range: 30Hz~20kHz
Nominal impedance: 8?
Sensitivity: 98dB
Drive units: 380mm paper cone Woofer , cloth surround, aluminum diecast basket
720mm Dome titan. compressive alt driver, rear-radiantion
Horn: Normal wood or piano wood, 110 degree level extension, built-in sound divider
Cabinet: MDF plate, normal wood surface, direct reflective acoustics structure
Crossover frequency:1000Hz
Dimensions: 1085*580*458mm(H*W*D)
Net weight: 60kg