Audio Nirvana Super8 Cast Frame
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With its build quality, sensitivity and performance, Super8 Cast
Frame is a typical sample of the Audio Nirvana line. The phase plug
is copper anodized, machined solid aluminum. The cone is made of
rigid yet very light paper. The surround is accordion style and made of cloth,
treated with a substance, that after more than six years of
operation is still soft and a bit sticky in touch.
This is the manufacturer's datasheet
for Audio Nirvana Super8 Cast Frame
My Measurements
Driver Properties | Thiele - Small Parameters | ||||
---|---|---|---|---|---|
Chassis material | Vacuum-molded aluminum alloy | Parameter | Measured | Datasheet | |
Membrane material | Paper | Fs | 48.3 Hz | 42.8 Hz | |
Magnet System | Neodymium | Re | 7.2 Ω | 7.2 Ω | |
Surround | Impregnated Cloth | Qms | 2.55 | 3.38 | |
Voice Coil Diameter | 32 mm | Qes | 0.18 | 0.184 | |
Nominal Impedance | 8 Ω | Qts | 0.17 | 0.175 | |
Sensitivity | 95.8 dB/W/m | Vas | 74 ltr | 73.3 ltr | |
Rated Power | 30W | Le | 0.15 mH | N/A |
This driver is suitable for back-loaded horn applications.
That's why I included a measurements in so-called "Universal" Horn.
More details about this project can be found
here.
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Frequency response at 1m with 2.83 V input RED - on axis, BLUE - 15 º off axis, GREEN - 30 º off axis
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The second, third and fourth harmonic curves measured at 2.83V input RMS.


Burst decay response, measured at 1m on axis
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
The impedance curves
Conclusion
As a typical Audio Nirvana driver, Super8 Cast has excellent sensitivity, pronounced trebles and excellent power capability. It can perform a loud music with ease and sureness. The aggression in the upper middle is perceptible, which should be corrected by a proper crossover network according to the listener's liking. Before start with corrections, the long break-in time (3 mints or more) should be taken into account. The only reasonable application for a driver with such a is backloaded horn. The best matching amplifiers are single-ended triode designs based on low internal resistance valves like 6П19П or 6C41C