Hello, all

Many woofers having a low Qts, their frequency range may be extended by means of the ~2 Ohm output impedance of a tube amplifier or an identical resistor added in series to the output of a transistor amplifier, at the expense of a larger enclosure size.

Consider, for example, a driver with a resonance frequency of 30 Hz, a Qts of 0.3 and a Vas of 50 litres. With a zero output impedance, a box of 11 litres is required to bring the total Q up to 0.707, in which case f-3 will be 75 Hz. But after adding a certain series resistance, the driver's Qtc may be raised to, say, 0.5 and a volume of 49 litres will be required for a flat frequency response with an f-3 of 45 Hz.

My question is: will the 11-litre and the 49-litre boxes be equally fast, i.e. have equally good impulse responses? Or in other words, are electrical and acoustic dampings thus interchangeable as long as the total system Q is the same? And if so, does it apply to vented enclosures as well?

Many woofers having a low Qts, their frequency range may be extended by means of the ~2 Ohm output impedance of a tube amplifier or an identical resistor added in series to the output of a transistor amplifier, at the expense of a larger enclosure size.

Consider, for example, a driver with a resonance frequency of 30 Hz, a Qts of 0.3 and a Vas of 50 litres. With a zero output impedance, a box of 11 litres is required to bring the total Q up to 0.707, in which case f-3 will be 75 Hz. But after adding a certain series resistance, the driver's Qtc may be raised to, say, 0.5 and a volume of 49 litres will be required for a flat frequency response with an f-3 of 45 Hz.

My question is: will the 11-litre and the 49-litre boxes be equally fast, i.e. have equally good impulse responses? Or in other words, are electrical and acoustic dampings thus interchangeable as long as the total system Q is the same? And if so, does it apply to vented enclosures as well?

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