Twochannel Reference Build — Neutral Sealed Separates

For a listener building a dedicated two-channel room around accuracy rather than a house sound, who wants full separates rather than a single integrated box. It rewards clean recordings and careful placement, and asks for an amplifier chosen to control the sealed 4-ohm load rather than the largest wattage on the shelf. Streaming is the primary source; no analog front end is included here.

The Magico A3 is a sealed three-way in a brace-heavy aluminum cabinet: two 7-inch Graphene Nano-Tec woofers, a Graphene midrange, and a beryllium dome, presenting a 4-ohm load at 88 dB. The sealed alignment matters more than the driver list. Without a port, the low end rolls off at a gentle 12 dB per octave from around 26 Hz, which trades maximum output for a shallow, predictable slope that room gain can fill in, and the cast-aluminum enclosure stores little energy of its own, so what leaves the drivers stays close to what the amplifier sends them. A speaker that adds so little of its own signature only earns its keep if everything upstream is equally self-effacing. That sets the brief for the electronics. The A3's published window runs from 50 to 300 watts, and the Bryston 3B³ meets the top of it exactly, delivering 200 watts per channel into 8 ohms and 300 into a 4-ohm load. Its damping factor of 500 and 0.005-percent distortion mean the amplifier is sized to reach the rating and stop there, keeping the woofers under electrical control through the lowest two octaves without inviting the over-excursion a much larger amplifier would permit on a sealed box. The Bryston contributes no warmth and no edge of its own; its job is current and control, nothing more. Ahead of it the signal passes through three more boxes, each isolated for one reason. The Innuos Zenith Mk3 serves files from its own storage over a wired connection and hands them by USB to the Denafrips Terminator Plus, an R-2R ladder converter that resolves PCM to 24-bit and DSD to DSD1024 at 0.001 percent distortion. Ladder conversion is chosen here for its linearity at low signal levels, where delta-sigma designs can lose resolution. The Terminator's balanced output, near 625 ohms, drives the Pass Labs XP-20 — a line stage split across two chassis so its power supply sits apart from the audio circuit — into a 48-kilohm input, and the XP-20's 200-ohm output in turn feeds the Bryston with the same margin. At every junction the source impedance is a small fraction of the load, so no interface tilts the response. The result is a system with no editorial hand of its own. The sealed cabinet, the ladder converter's low-level linearity, the two-chassis preamp's isolation, and an amplifier chosen to control rather than dominate all point the same direction: reproduce the recording and add nothing. Neutrality of this kind is only convincing if it holds top to bottom, and the weakest permitted link would be an amplifier that ran out of grip into the 4-ohm load. That is exactly why the Bryston, sized to the A3's ceiling rather than a higher-wattage design that would coast past it, is the correct partner rather than merely a powerful one.

Neutrality gives nothing away for free. The A3's flat, sealed balance renders sibilance, compression, and thin mastering exactly as recorded, so a library of loud modern pop will sound as hard here as it was made. The sealed alignment also caps output and reach: usable bass runs out near 26 Hz and, lacking a port's boost, needs room reinforcement or a subwoofer to feel the lowest synth and organ notes. The 88 dB sensitivity means this is not an efficient, low-power setup — the 4-ohm load wants the current the Bryston supplies and would starve on a low-powered amplifier. Five separate boxes also mean five power cords, four interconnects, and real rack space, plus the setup discipline a resolving speaker demands; small changes in toe-in and the gap to the front wall move the tonal balance more than any electronics swap will.

• 01

  Swap 3B³ → X250.8 (+$5,555)

  Trading the Bryston for the Pass X250.8 keeps the neutral aim but adds first-watt Class A operation and a much heavier power supply: 250 watts into 8 ohms with deeper reserve into the A3's 4-ohm load and a slightly denser tone, at a higher price and far greater heat and mass.

• 02

  Swap A3 → A5 (+$13,100)

  The A5 keeps the sealed, aluminum-cabinet neutrality but scales it up to a larger three-way with 24 Hz reach and a 50-to-1000-watt power window, so it plays louder and lower in a bigger room. Exploiting that ceiling means moving past the 3B-cubed to a higher-current amplifier, so this is a two-part upgrade rather than a single swap.