I am fortunate to own the TAD Ref 1 for a little over 4 years now. During this time I have many friends that have brought their preamps, dacs and amps over to evaluate the sound and the TADs have sounded well with all the equipment. Most equipment that was used would be considered Hi-End. The only issue is the base control with some tube amps. I have CAT JL3 Signature Mk2 monos which cannot control the 2 12" woofers well enough. I also have Pass Labs XA 160.8 monos that do a fantastic job with woofer control. The 'beryllium concentric driver has a richer sound that delivers a predictable sound that IMHO is fantastic. I evaluated many high end speakers before I decided on the TAD because they produced a richer sound.