Reference 3a Royal Master Control loudspeaker

[Stereophile]

<img src="http://www.stereophile.com/images/8883aroyals.1.jpg" alt="8883aroyals.1.jpg" width="250" height="191" border="0" align="right" />The match between amplifier and speaker for single-ended operation is critical, which is why John Atkinson suggested I let Wavelength's <a href="http://www.stereophile.com/interviews/196rankin/index.html">Gordon Rankin</a> lead when it came to choosing a speaker to partner his special-edition <a href="http://www.stereophile.com/tubepoweramps/196wavelength/index.html">Cardinal</a> amplifiers. If you're not talking roughly 92dB sensitivity and a fairly benign load, say no lower than 6 ohms, you're just not talking single-ended. That precluded running the Cardinals on the big Avalon Ascents with their lowish 86dB sensitivity (in spite of the relatively benign impedance curve).
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After more discussion it became evident that the best speakers to use were the very ones Gordon employed in his own reference system

[Source: http://www.stereophile.com/content/reference-3a-royal-master-control-loudspeaker]