Sonido SFR-175 Alnico
After the successful presentation of its fullrange drivers on the market, Sonido introduced Alnico magnet line. I took a sample of SFR-175 AlNiCo thanks to my friend Peter Haralanov - an audiophile from Bulgaria.
The Alnico series has the same paper as the ceramic drivers.
We can see the manufacturer's stamp on the back
The surround is coated textile with accordion shape.
The driver has a wooden phase plug, fastened with a screw through the
magnet system and can be easily removed.
This is the manufacturer's datasheet
My Measurements
| Driver Properties | Thiele - Small Parameters | ||||
|---|---|---|---|---|---|
| Chassis material | Die-cast aluminum alloy | Parameter | Measured | Datasheet | |
| Membrane material | Paper | Fs | 54.2Hz | 54 Hz | |
| Magnet System | AlNiCo | Re | 6.9 Ω | 7.2 Ω | |
| Surround | Impregnated Paper | Qms | 5.1 | 14.7 | |
| Voice Coil Diameter | 28 mm | Qes | 0.43 | 0.35 | |
| Nominal Impedance | 8 Ω | Qts | 0.42 | 0.34 | |
| Sensitivity | 92.7 dB/W/m | Vas | 21 ltr | 27 ltr | |
| Rated Power | 24W | Le | 0.24 mH | 0.25 mH | |
Frequency response at 1m with 2.83 V input RED - on axis, BLUE - 15 º off axis, GREEN - 30 º off axis
On the right - the frequency response with the phase plug removed.
The second, third and fourth harmonic curves measured at 2.83V input RMS.
Burst decay response, measured at 1m on axis
The impedance curve in 18 ltr sealed box
Conclusion
SFR-175 Alnico is full-bodied fullrange driver with calm and detailed performance. It is suitable for various enclosures as well as an open baffles.
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