Any budget conscious recommendations?
The
AudioSource AMP-100 looks interesting, for a very low price, although I have no particular familiarity with it. It includes a volume control, which would allow you to adjust the relationship between the volume of the speakers it is powering and the volume of the other speaker.
Here are links to the manual and manufacturer's description.
... purchase a separate power amplifier and drive the Energy speakers in series from that.
That amp is rated to drive 4 ohms, corresponding to two 8 ohm speakers in parallel. It's hard to predict how well it would handle driving the two Energy speakers in parallel, in part because the range of frequencies at which they dip to their 4 ohm minimum (which would be 2 ohms for the parallel combination) is not specified. It might be worth trying the parallel connection, though. A series connection would in effect convert the 50 watt amp into approximately a 12.5 watt amp as far as each speaker is concerned, since each speaker would see only half of the voltage the amp is supplying (1/2 voltage = 1/4 power). The amp is rated to supply 61 watts into 4 ohms, or 30.5 watts into each of the speakers if they are paralleled.
If you try the parallel connection, listen for signs of distortion on musical peaks, especially on drum beats and other high volume bass notes.
Regards,
-- Al