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driver assuming only 0.1 ohm Rg for the source amp. The Qa was set at 15, indicating a reasonably

heavy stuffing, and the enclosure was adjusted to result in a modeled Qtc of 0.707, or 28.8 liters. Now I

increased Rg to add the cable resistance, the DCR of the inductor, and the voice coil heating effects.

For the purposes of this example, I assumed 0.4 ohm, which is about a 6% increase in Re, rather than

the 8% of the Stereophile article. Taking all the factors in account, this adds another 0.9 ohms to the

series resistance. The result is the cyan curve. Now the modeled Qtc has increased to 0.767, and

resulted in roughly a 0.5 dB loss above 75 Hz. To retain a .707 Qtc under these conditions the box

enclosure would need to be increased to 37.8 liters, or over 30% larger. -But with the extra volume

comes a 5 Hz extension in f3. This is shown in the red curve.

Continued...

Electrical Factors affecting system impedance -And their consequences on system Q |