2026: Arrival. The AMP-54R from Stockholm first parachuted into my downstairs stereo 2.1 rig whose dual 15" sound|kaos sub's primary purpose is acoustic room treatment. It cuts bass reflections by well more than 50% via quasi cardioid dispersion. That's from a classic figure-8 dipole pattern rendered still more directional by the RiPol aka Axel Ridthaler dipole principle. In addition, below 150Hz two active PSI Audio bass traps absorb pressure build-up in the front corners. At 100Hz/4th-order, a Lifesaver Audio Gradient Box II crossover splits the signal into a high pass (Dazzle amp, IQ speakers) and low pass (Ncore 500-based Nord Acoustic mono amp, subwoofer). My room's 35Hz and 70Hz primary modes now fall into the RiPol dispersion and PSI absorption window. Hello effectively bass-treated room without huge passive traps. In crossover bypass via remote, the sub gets no signal, the speakers uncut signal to 20Hz. Whilst this shows an amp's performance over the speakers' rear-ported 9½" SB Acoustics Satori woofers, it also reactivates sub 100Hz room response. That instantly triggers typical narrow-band modal ringing and nonlinear room gain. So my default review mode is 2.1. Its bass is far cleaner. Volume control is by passive-magnetic multi-tapped autoformers in another Lifesaver Audio product, the petite icOn 4Pro shown below on the sidewall rack displaying '31'.
The front end is a 40GB RAM 27" iMac hosting Audirvana Studio with embedded Qobuz Sublime account. Separately there is Spotify Lossless. Local files live on an external 4TB SSD and run through Audirvana. Cloud files encounter two slaved LHY Audio LAN distributors. The SoX upsampler in Audirvana handles x 4 upsampling before that USB signal hits a Singxer SU-6 super-cap-powered USB bridge. That dispatches reclocked digital signal via AES/EBU to a Sonnet Pasithea R2R DAC. Alternate source is a Denafrips CD transport set to 176.4kHz upsampling. Kinki Studio Tai Hang DC filters and current conditioners handle power delivery for both the sidewall and front-wall hardware. The Enleum would dock atop the Dazzle in fixed-gain mode. My little pond was ready for its frog whose skin John DeVore calls a greenish grey. Most appropriate then.
Going for seconds would happen in this upstairs system. That too exploits a 2.1 labour split but here at 40Hz given this 15-inch sub's classic omni dispersion where higher bandwidth would cause more room involvement. The Zu Method sub runs off a built-in Hypex Fusion amp whose DSP I set to be +3dB at 20Hz. The Virtual Cobra monitors run off Kinki Studio EX-B7 monos. The active analog crossover sits in another Lifesaver Audio box, a large custom autoformer passive. The offline front end starts with a FiiO R7 as SD-card USB streamer run off a SilentPower iPower Elite external PSU. A Soundaware super-cap-powered D300Ref USB bridge reclocks that signal then outputs I²S/HDMI into a Cen.Grand DSDAC 1.0 Deluxe set to fixed gain and DSD1'024 resampling. Here the AMP-54R would replace DC-coupled 250W class AB monos.
That covered the ancillary x's and o's. Time for the physical inspection.
