BRUEL & KJAER 2672, Руководство пользователя

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Chapter 4 — Using Type 2672
Filters
Sound Quality Conditioning Amplifier Type 2672
User Manual
BE 1461 –11
4
−
5
4.5.2 Overload
Each channel has an overload warning light (Ovld.). These light when the signal
exceeds 5 V rms.
4.6 Filters
4.6.1 High-pass
The high-pass filters filter out unwanted low-frequency noise. They are second order
filters with a 12 dB/octave cut-off. You can set the lower cut-off frequency (–1 dB) for
each channel to 0.3, 10, or 20 Hz.
4.6.2 DFCF
This is the Diffuse Field Correction Filter for use when making binaural recording
using HATS Type 4100 or 4100 D.
This diffuse-field response (see Fig.4.2) of HATS Type 4100 (D) is given on the cali-
bration chart provided with the simulator. As can be seen in Fig.4.2, the response
is far from flat, and normalisation is usually required. This is achieved by equaliza-
tion in Type 2672 (DFCF On), before the signals are processed and recorded on a
DAT recorder, and can improve the signal-to-noise ratio by as much as 10 dB in the
frequency range 2 – 6 kHz.
Fig.4.2 Diffuse-field characteristics of the head and torso simu-
lator
10
5
dB
0
- 5
- 10
- 15
950516e
Frequency (Hz) 200 2000 20000
Right ear Left ear