STIPA male
Recommended EQ / DSP setting when using a STIPA test signal at maximum level:
Apply a high‑pass (HP) filter at 300 Hz–400 Hz with a 12 dB/octave Butterworth slope.
Note:
Why does the achievable sound pressure level improve when the signal is filtered?
Frequencies below 250 Hz are hardly transmitted by the tunnel horn, so the level in the 125 Hz band can be reduced.
This frees up output voltage in the 100‑volt amplifier for the remaining third‑octave bands.
Impedance Measurement
Please ensure that the horn’s sound‑exit opening is not blocked during the measurement, for example, by resting the
horn on the floor. Any obstruction will lead to inaccurate readings.
Some impedance meters take measurements at a fixed frequency - usually 1 kHz. Because resonances are present at that point,
the meter can indicate an impedance that is too high and does not reflect the actual power consumption (see diagram)