AVR for 4-Ohm Speakers
As it turns out, AVRs that can comfortably drive 4-ohm speakers are not common, at least among HT's AVR Top Picks. Of the six models in our midrange price class ($800-$2500), only two are specified to be able to handle a 4-ohm load—the Integra DTR-50.2 ($1400, reviewed here) and Onkyo TX-NR1009 ($1399, reviewed here), which provide Audyssey MultEQ and MultEQ XT room correction, respectively. Integra and Onkyo are corporately related, so it's no surprise that both have similar capabilities in this regard.
Of the remaining midrange Top Picks, the Pioneer Elite SC-57 ($2100), with its class-D amps, and VSX-52 ($900, not class-D) are both specified down to 6 ohms, as is the Marantz SR7005 ($1600). The specs for the Anthem MRX 700 ($2000) do not include a range of acceptable speaker impedances, but its power ratings are given only for 8 ohms. Too bad, because its Anthem Room Correction is said to be nothing short of amazing.
Your FC8s have a specified power-handling capacity of 20-300 watts, while the Stratus Silveris can handle 15-250W with a recommended program power of 200W. The DTR-50.2 and TX-NR1009 specs include a dynamic power of 250W into 4 ohms.
Looking at HT's measurements of the DTR-50.2, with two channels driving 4-ohm loads, the amp reached 0.1% distortion at 200.4W and 1.0% distortion at 259.8W. The same measurements of the TX-NR1009 yielded 218.1W and 250.4W, respectively.
These results are very similar and well-suited to your speakers, and the two units are virtually the same price, so I'd say it's a toss-up for you. I'd probably go for the Onkyo with its MultEQ XT room correction, which uses higher-resolution filters than the older Integra's standard MultEQ—plus the Onkyo provides nine amp channels as opposed to seven in the Integra.
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