Macworld - USA (2019-12-B)

DECEMBER 2019 MACWORLD 119

of them overheating (though I would err on
the side of caution and add some active
ventilation if I was stacking them in an
enclosed entertainment center).
The Sonos Amp is ostensibly a retail
product, but it was designed to also
address the needs of custom installers
who might mount a bunch of them in a
component rack. The Amp measures 1.5
RU high (2.52 inches) and is 8.54 inches
square. This enables them to be mounted
two abreast in a standard 19-inch rack.
The Amp doesn’t have rack-mount
ears, but it is outfitted with a standard M5
thread mount on its bottom. At a press
event at Sonos’ Boston headquarters late
last year, Sonos Amp product manager
Benji Rappoport showed me an actively
cooled rack cabinet holding 32 Amps.

SONOS AMP LISTENING TESTS
I first tested the amplifier with four very
different stereo speaker pairs, one pair at a
time. I used Q Acoustics’ Concept 20 (go.
macworld.com/qa20) bookshelf speakers (6
ohms nominal impedance) in my home
theater; Bowers & Wilkins’ 603 tower
speakers (8 ohms nominal impedance, also
in my home theater); B&W’s M-1 Mini
Theatre satellite speakers (8 ohms nominal
impedance) mounted high on a wall in my
great room; and Focal’s Custom OD 108
outdoor speakers (go.macworld.com/fcod)
(8 ohms nominal impedance) mounted high

on a wall in my enclosed patio. For the tests

with the M-1 Mini Theatre (the smallest of

the three sets of speakers by far), I paired

the Amp with a Sonos Sub.

The Amp performed like a champ with

each set of speakers. Volume didn’t get

loud enough to drive me out of the room

while listening to the two-way Q Acoustics

bookshelf (1-inch tweeters and 5-inch

woofers) or the three-way B&W tower

speakers (1-inch tweeters, 6-inch mid-

range, and dual 6.5-inch woofers), but

both combinations easily filled my home

theater without the need to crank the

volume to the max.

Listening at more moderate—and

The first step of

the Sonos Sub

tuning process

plays a rapid-

fire bass line in

an A/B listening

test that lets you

evaluate the

Sub’s phase.