I cannot speak for the Argent Room Lens, but the Walker HDI is a very worthwhile high level tweak. It should probably be added after everything else in the system is mostly correct to fully appreciate it's value.
To put price in perspective, the HDI at retail is about the same investment as a foot (or less) of the interconnect cables usually found in a high end system.
The performance is distinctly audible with my Soundlab speakers, adding impact and dynamics to the bass frequencies and smoothing the extreme high frequencies while improving depth of image. I have had others tell me that similar performance gains were had with dynamic speakers as well.
To put price in perspective, the HDI at retail is about the same investment as a foot (or less) of the interconnect cables usually found in a high end system.
The performance is distinctly audible with my Soundlab speakers, adding impact and dynamics to the bass frequencies and smoothing the extreme high frequencies while improving depth of image. I have had others tell me that similar performance gains were had with dynamic speakers as well.