We're looking at a complete DEQX system; DEQX HDP-5 preamplifier/digital linear phase crossover/frequency & group calibration and room compensation/Roon certified end point, DEQX A250x3 monoblock 3 channel amplifier, DEQX/Legen Acoustics ISR active monitors ($16995/system). Frequency response is a reported 100Hz - 10kHz (+/- 0.5dB anechoic).

While you can buy the HDP-5 ($5995) and A250x3 monoblocks ($2795/pair) separately, the speakers are only available as part of the full monty. DEQX has been at this room correction game for a long time, since the mid-1990s, so they've had plenty of time & experience to hone their skills.

From my brief listening to some lovely analog tape, their work has paid off.