miniDSP EARS, User Manual

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miniDSP Ltd, Hong Kong / www.minidsp.com / Features and specifications subject to change without prior notice
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Measurements are easier to interpret if some smoothing is applied to the graph. This can be done from the main
Graph menu. For most purposes, we suggest using 1/12
th
-octave smoothing, as illustrated in Figure 3.
3.2 O
THER TYPES OF MEASUREMENT
The bar along the top of Figure 2 can be used to select other types of measurement. Some of these will be the
subject of future app notes on our web site, but here is a brief overview of the most relevant and useful for
headphones (and IEMs):
All SPL Shows multiple SPL measurements. To take an average of several measurements, click All SPL
and select the ones that you want to average using the checkboxes at the bottom. Then click on
the Average the Responses button.
Distortion Displays measured harmonic distortion versus frequency. The graphs are displayed in dB, but
you can read off the distortion in percent at any frequency by placing the cursor on the graph,
then reading off the distortion % next to the graph names underneath.
Impulse EARS is not suited for impulse response measurements unless the measurement program uses
the phase information in the EARS calibration file when it displays the impulse response. REW
doesn
’ t currently do this.
Waterfall The “waterfall” or CSD (cumulative spectral decay) plot is a hybrid time -and-frequency display
that is useful to show resonances in the response. Note: while it seems likely that a headphone
with a “clean” CSD will sound better than a headphone with a “messy” CSD, we are not currently
aware of formally-published research in this area.
Another type of measurement you will see in some online measurement sets is the headphone impedance vs
frequency. EARS can
not be used to make impedance measurements.
EARS is also not well suited for sound isolation measurements, as the omnidirectional microphone capsules pick
up sound from the
back of the “ear,” limiting the maximum attenuation that can be m easured.
Figure 3. The effect of smoothing on a graph