98 August2019nstereophile.com
DUTCH & DUTCH 8C
measurements, continuedatop a sturdy 24"-high Sound
Anchors stand. The combination
looked top-heavy but felt stable
and welded to the floor. I began
by placing them where I usually
place stereo speakers: about 6'
from the front wall and about 8'
apart. While that wasn’t nearly as
close to the front wall as D&D
recommends, it was a familiar
starting point and made it easy to
access the controls on the back
panel.
First, I plugged my Audio
Research MP1 preamplifier’s L/R
analog outputs into the D&Ds,
but at either sensitivity, even with
the MP1’s prodigious voltage out-
put, I could barely hear anything.
It wasn’t going to be that easy.
I plugged an Ethernet link into
each 8c and, following instruc-
tions, I used my computer’s web
browser to visit lanspeaker.com,
the site where Dutch & Dutch’s
web-base app resides. The website
found both speakers and told me that their volume controls
had been set very low at the factory. I linked the two speak-
ers so that I could control them as a pair, turned them up,
and they sang. The sound was clean and sweet, with a nar-
row soundstage with solid center fill. Sorta small.All connections and con-
trols are on the lower edge of
the rear panel. Beginning at
far left, there is a plate with
the serial number, followed
by four signal connectors, the
first three XLRs. The first
of these is the main audio
input, which can function as
a balanced analog input or as
an AES3 digital input. When
used as the latter, the adjacent
output provides throughput
to another 8c,^5 and each
speaker can be assigned the
left, right, or both chan-
nels of a stereo source. The
third XLR is a full-range,
DSP-controlled subwoofer
output. (At review time, the
software supporting this was
not yet available.) The last
connector, an RJ45, is es-
sential for setting up the 8c’s
DSP functions and can also
support playback via the local
network. Next is a small pushbutton for selecting analog and
digital inputs, analog input sensitivity, and choice of digital
channel; next to this is a column of LEDs that indicate the
user’s selections. At far right are the inlet for the power cord,
the fuse bay, and the main on/off switch.
Setup
It took a bit of wrestling, but I managed to place each 8c
24kHz. This suggests that the 8c’s
internal digital signal processing oper-
ates with a sample rate of 48kHz.
I couldn’t find a setting in the web
menu to change the DSP sample rate,
but to see if this was the case only
with analog input data—ie, to see if
the analog input’s A/D converter runs
only at 48kHz—I fed the speaker AES/
EBU digital data sampled at 96kHz
and repeated the on-axis frequency-
response measurement. The result
was the same: a sharp rolloff above
20kHz and a Nyquist frequency of
24kHz. As a final check, I set the 8c’s
analog subwoofer output to full range
with the website app and analyzed its
analog output signal while I fed the
speaker 96kHz digital data. There was
no difference. It appears that Dutch
& Dutch’s DSP operates at a fixed
48kHz sample rate, and that digital
data with a higher sample rate are
downsampled.
The blue trace below 300Hz infig.2 shows the response of the 8c’s
front-panel midrange woofer measured
in the nearfield. The upper-bass rise
is due to the nearfield measurement
technique, which assumes that the
drive-units are mounted in a true
infinite baffle—ie, one that extends
to infinity in both the horizontal and
vertical planes. The driver’s output rolls
off below 100Hz with what appears
to be an 18dB/octave slope. The redtrace is the nearfield output of the two
subwoofers mounted on the 8c’s rear
panel, plotted in the ratio of the square
roots of the woofer’s and subwoof-
ers’ radiating areas. The subwoofers
cover the range from 20Hz to 100Hz,
with a steep rolloff below 20Hz. To my
surprise, however, two sharp notches
can be seen in this graph. I recon-
nected the speaker to the network and
checked the controls with the websiteFig.3 Dutch & Dutch 8c, lateral response family at
50", normalized to response on tweeter axis, from
back to front: differences in response 90–5° off
axis, reference response, differences in response
5–90° off axis.Fig.4 Dutch & Dutch 8c, vertical response family at
50", normalized to response on tweeter axis, from
back to front: differences in response 15–5° above
axis, reference response, differences in response
5–15° below axis.5 After the output of the first 8c is connected to the input of the second 8c, a
termination plug (provided) must be inserted in the second speaker’s Throughput
output.