I see folks here frequently recommending using a crossover between stand mounted loudspeakers and sub woofer. I've been running my Harbeth Compact 7es-3's full range along with various sub woofers using only low pass filters. I hear the Harbeths straining at higher volumes and now I'd like to try using a high pass filter with the Harbeths. My electronics are Benchmark DAC2HGC and AHB2. I'm looking for recommendations for a high quality, low noise active crossover between the Harbeths and 2 subs.