Dayton Audio DATS Dayton Audio Test System - Manual (Page 4)

seem like a high percentage, but never exceeds 0.025 Ohms. From the raw measurement data shown
in the appendices it is clear that the repeatability of DATS measurements is excellent, and in some
instances the same value is measured for all ten measurements. Frequently the first three digits are
constant for all ten measurements, indicating excellent measurement precision.
Unit ID 1000 Ohms 100 Ohms 10 Ohms 1 Ohms
A -.032% +.040% -.131% -2.179% (-.022 Ω)
B -.023% +.034% -.108% -1.899% (-.019 Ω)
C +.132% -.329% -.482% -2.142% (-.021Ω)
D +.162% +.146% +.065% -.815% (-.0081Ω)
E +.047% +.301% +.284% -.083% (-.0008Ω)
F -.032% -.015% -.299% -1.604% (-.016Ω)
Figure 4: Mean measurement error for ten trials at each impedance for each unit.
The six test units performed with accuracy better than +/-1%, except at 1 Ohm, where the highest
percentage error was -2.179% for unit A. This may sound high until you realize that the actual error
never exceeded 0.025 Ohms. The accuracy specification for these six units (calibrated to +/-
0.1% at 1k Ohms) would be +/- 0.5% or .025 Ohms, whichever is greater. When calibrated with a
1% resistor the accuracy specification would be degraded to +/- 1.5% or .035 Ohms, whichever is
greater. Similar testing on capacitors and inductors reveals this same high level of accuracy. Out of
the box and uncalibrated, it is normal for DATS units to exhibit a basic accuracy of around +/-5%.
References:
[1] A. N. Thiele, “Loudspeakers in Vented Boxes: Part I and II, Loudspeaker Anthology, vol. 1
(Audio Eng. Society, New York, 1978).
[2] R.H. Small, “Vented-Box Loudspeaker Systems, Part I: Small-Signal Analysis, “J. Audio Eng.
Soc., vol. 21, (June 1973).
[3] Joseph D’Appolito, “Testing Loudspeakers”, published by Audio Amateur Press, 1998.