Phil,
The LS3/5 might beat the Spica on tonal accuracy ... I'll admit that. But the margin of victory would be quite small IMO.
On the other hand when it comes to imaging and casting a wide deep soundstage there is no competition. The LS3/5 is not even close to the Spica. It is this that makes the Spica such a legendary speaker.
As to the issue of impedance I would think it would depend on the amplifier, its rail voltages and its ability to deliver current and double its power into 4ohms. Some amps can't deliver current (older Quads) and sound much better into high impedances. Others (Cyrus, Densen to name a couple) deliver current in spades and seem much less fussy about impedance.
The LS3/5 might beat the Spica on tonal accuracy ... I'll admit that. But the margin of victory would be quite small IMO.
On the other hand when it comes to imaging and casting a wide deep soundstage there is no competition. The LS3/5 is not even close to the Spica. It is this that makes the Spica such a legendary speaker.
As to the issue of impedance I would think it would depend on the amplifier, its rail voltages and its ability to deliver current and double its power into 4ohms. Some amps can't deliver current (older Quads) and sound much better into high impedances. Others (Cyrus, Densen to name a couple) deliver current in spades and seem much less fussy about impedance.