My estimate of the Vivid B1's voltage sensitivity was a little lower than specified, at 87dB(B)/2.83V/m, which is about average. The speaker is specified as being a 4 ohm load, presumably because, as can be seen in fig.1, the impedance drops to a minimum of 3 ohms in the low midrange and remains below 6 ohms for most of the region below 700Hz. However, the high impedance in the treble compared with the midrange will shelve the speaker's high frequencies up if it is used with a tube amplifier possessing a high source impedance, as most of them do.
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