SP395 SoundPro Audio Integrator Form7492 Operation Manual
52
the TDA test. You can switch directly between the Setup Screen and the Run Screen within the
Setup/Run field. All setup screen fields are described below.
TDA Setup Screen and Control Fields:
1. Test Function – identifies the current test function MB-RT60 (Multi-band RT60).
2. Setup/Run – switches between the TDA Setup Screen and the TDA Run screen. The
TDA Setup Screen provides selection for configuring the TDA test. The TDA Run screen
provides the test results.
3a. Initial Delay of Distance (Value) – Enter the speaker to microphone distance so that the
TDA function can compute Ts and offset the input filter correctly with respect to the
sweep generator. Selects distance in 0.1 increments from 0 ft. to 999.9 ft.
3b. Initial Delay or Distance (Units) – selects the unit of measurement used to set speaker
distance either feet (ft) or meters (m). Select between m (meters) or ft (feet).
4. Sweep Time – Sets the time for the generator to sweep the TDA through the range of 20
Hz to 20 kHz. Variable from 7-30 seconds.
5. Sweep Delta – This field sets the additional delay time between the generator sweep and
the filter sweep for each consecutive sweep. Note that, if you are running a single sweep,
this field has no effect.
6. Number of Sweeps – Specifies how many subsequent sweeps are performed ranging
from 1 to 20.
7. Filter Q – The Filter Q field controls the steepness or sharpness of the band-pass filter
skirts ranging from 2 – 50.
8. Space Equivalent Bandwidth (S.E.B) – This field is not selectable.
9. Space Equivalent Values in ft. and mS – Indicates S.E.B. values computed from the
Sweep Time and Filter Q selections. Values describe a distance and/or time in which
reflected sound is significantly reduced in level 3 dB.
Initial Delay – Enter the speaker to microphone distance so that the TDA function can compute
Ts and offset the input filter correctly with respect to the sweep generator. However, this delay
value is not as critical as it is with other time delay analysis methods, since we are sweeping an
actual filter, rather than deriving the response through convolution of an impulse response, or
with a dual FFT transfer function. These other methods require very accurate Ts measurements.
With the SP395 TDA method, an incorrect Ts time simply results in a graph that is shifted
slightly on the frequency axis.
You can simply measure the distance with a tape measure (in feet or meters), or you can use the
Energy Time Graph to measure the initial delay time.
Sweep Time – Sets the time for a single sweep, from 7 seconds to 30 seconds. A shorter sweep
time completes faster, but a longer sweep time gives more low frequency energy, and more
accurate results. Sweep time interacts with filter Q to determine the Space Equivalent
Bandwidth. See below.
Sweep Delta – This field sets the additional delay time between the generator sweep and the
filter sweep for each consecutive sweep. Note that, if you are running a single sweep, this field
has no effect.
Number of Sweeps – You can set the number of sweeps from 1 to 20. Normally, you run one
sweep if you are testing a transducer, and you run multiple sweeps if you are testing room decay
and wish to create a set of curves.
To Next Page
Loading...
