The Interface D combines the best qualities of the finest speakers in the world without their weaknesses. The result is a new standard of accuracy, efficiency and overall performance.
There are speakers with exceptional midrange definition. And speakers with deep bass or exceptional stereo imaging.
Really of 28 Hz
The Interface D's bass response is virtually unprecedented. Its 3-dB-down point is 28 Hz. And unlike some speakers which have limited output at low frequencies, the Interface D can produce an incredible 106 dB long-term sound pressure level at 28 Hz.
The bass is also smooth. This is due in large part to placing the 12" woofer in a downward-firing position. This couples it to the floor and wall which smooths the response, by eliminating boundary effects caused by front mounting, and efficiency is increased by 3 dB.
A new kind of midrange
The efficiency and high output ability of the woofer made almost impossible demands of the midrange. In fact, it would have been impossible to design a midrange driver of reasonable size, high efficiency, high output and low crossover point using conventional speaker technology. So we designed our midrange using the same optimally vented technology we pioneered for woofers.
This optimally vented midrange uses exactly the same 16-pound magnetic structure as the woofer. So it can deliver long term sound pressure levels of up to 115 dB and peaks up to 125 dB. At the same time, it's small 6-1/2" cone provides excellent dispersion over its entire frequency range.
Without vented technology, a small cone couldn't produce high sound pressure levels at low frequencies - it just couldn't move enough air. But the self-contained, vented enclosure solves that problem. The enclosure and vent size are critically selected so at low frequencies, a small movement of the cone produces a large movement of the air in the vent. Over the lowest itself provides most of the system's output.
The exceptionally low crossover (350 Hz) made possible by the optimally vented midrange has an important audible result. There is no crossover in the most critical part of the vocal range. At last you'll hear an almost unbelievable clarity and definition. It's the "sweetness" many audiophiles associate with electrostatic speakers, but without their inherent weaknesses.
The tweeter without "horn sound"
This tweeter has natural, accurate sound and has significant advantages over conventional cone and dome drivers.
It is 10 dB more efficient than any cone or dome could possibly be. And it can play louder than conventional tweeters. This additional output is extremely important in contemporary music. At realistic volume, synthesizers and closemiked brass or percussion make severe demands of a tweeter. Thanks to its horn tweeter, the Interface D reproduces that kind of music accurately.
The third advantage of our horn tweeter is equally important-unusually uniform and well-controlled horizontal dispersion over its entire frequency range. The dispersion of all cone and dome drivers varies with frequency. At low frequencies, dispersion often exceeds 180 degree which causes severe diffraction from the edges of the cabinet. This result in cancellation effects and less uniform total acoustic power output. But a higher frequencies, conventional tweeters have much narrover dispersion. These constantly changing dispersion angles result in a vague, blurred stereo image.
But the Interface D's dispersion is tightly controlled by the 120 degree angle of the horn. Even at low treble frequencies, dispersion remains well under 180 degree, eliminating diffraction effects. And even above 16,000 Hz dispersion is better than 110 degree.
Specifications
Frequency Response: 23 - 20,000 Hz ±3 dB, 28 - 18,000 Hz , 1 m on axis
Total Acoustic Power Output: ±3 dB, 28 - 18,000 Hz
Horizontal Dispersion:
Angle 170° ±5° in the 500 - 1000 Hz octave bands
Angle 115° ±10° in the 2000 - 16,000 Hz bands
Anglw 110° in the 16,000 Hz band
Recommended Amplifier Power: 1,5 watts per channel minimum; 500 watts max
Sound Pressure Level: 97 dB at 1W/1m
Midband Sound Pressure Level (in a Typical Listening Room):
90 dB average, 100 dB peak with a 1,5 watt amplifier;
115 dB average, 125 dB peak (10 ms) with a 500 watt amplifier.
Maximum High Frequency Sound Pressure Level( In a typical Listening Room): 103 dB long-term average (10,000 Hz)
Midband Power Capacity: 50 watt long-term average; 500 watts peak (10 ms)
Crossover Frequencies: 40 Hz acoustic, 350, 3000 Hz electrical (may be bi-amplified at 350 Hz)
Transducers:
12" downward-firing woofer
6-1/2" vented midrange
Radial horn tweeter
Impedance: 8 Ω nominal; 5 Ω minimum
Controls: Environment slope (0 dB, -3 dB, -6 dB, -9 dB at 10,000 Hz)
Dimensions (H x W x D): 32" x 21-3/4" x 15-1/2"
Weight: 114 lbs
Cabinet: Walnut veneer