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A new step in speech intelligibility measurements
With the introduction of Dirac 6 and the Echo speech source,
speech intelligibility measurements can now be performed faster and more accurately than ever.
The Echo delivers acoustical stimuli used by Dirac to measure different speech intelligibility parameters.
These stimuli are fully calibrated, so it is no longer necessary to work with an external equalizer
or to set the signal output level to comply with the standards.
The Echo-Dirac combination also performs very well at high background noise levels.
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The Echo Speech Source
- Fully calibrated sound levels and spectra
- Reference level of 60 dB(A) at 1m
- Raised level of 72 dB(A) at 1m
- Continuous or Intermittent Noise stimuli
- Calibrated human Test Voice
- Adaptor for common tripods
- External input and output
- Compact: 10x10x17 cm
- Lightweight: 1 kg
- Battery powered: 24hrs continuous
- Mains power supply included
- Optional protective carrying case
You can see how easy it is to measure the speech intelligibility
using the Echo speech source in this video.
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Innovative stimuli
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Dirac 6 and the Echo speech source make use of a special intermittent pink MLS signal.
This signal consists of a pink filtered MLS followed by a period of silence during
which the background noise is recorded. The use of MLS signals in a stand-alone device
such as the Echo is made possible by Dirac's advanced handling of asynchronous
signals.
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The pink MLS signal is discreet as compared to sweeps or modulated noise signals,
because it more closely resembles common background noise signals, such as traffic or HVAC noise.
Its pink frequency spectrum, optimal for acoustical measurements, enables the use of a small loudspeaker,
making it possible to fit everything in a tiny box.
Background noise is captured during the silence part of the stimulus, and stored in the second channel
of a dual channel measurement file. In this way, you will also have accurate background noise levels
together with the measured impulse response. Speech and noise levels may be altered manually for analysis
of 'what-if' scenarios.
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ISO 3382-3 Open plan offices
The intermittent stimulus is also used for measurements in open plan offices.
ISO 3382-3 requires 4 quantities being measured at each measurement position,
and in Dirac 6 that only requires a single measurement.
From the measurements at multiple positions in the office,
Dirac calculates the parameters STI, LP,A,S,
LP,A,S,4, D2,S, rD and rP.
The STI, the LP,A,S and most other parameters can be graphed versus
the source receiver distance with optional regression lines.
Find out how to perform ISO 3382-3 measurements using Dirac in this video.
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New in Dirac version 6
- Support for the Echo speech source.
- Time saving intermittent stimuli.
- All parameters required by ISO 3382-3
- Graph parameter values versus the source-receiver distance.
- Continuous MTF graphs.
- Load and save measurement setups in the measurement window.
- Multi-channel import (also B&K PULSE files).
- New level parameters: Lmin, Lmax, Lpeak and LN with A/C/Z frequency- and F/S time-weighting.
- Display Leq and derived values for measurements with pink stimulus.
- Improved support for ASIO sound devices.
- Automatically add new measurements to a parameter graph.
- Export displayed data (ETC, spectrum etc.).
- Many more additions and changes.
Some of the new features of Dirac are presented in this video.
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