Phonic PCR2213, Руководство пользователя

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27. OK, now the HF is correctly sent into HF speaker(s). Un-mute the MF output, and mute the HF output.
Keep LF muted.
28. Turn on the MF power amplifier and slowly turn up the level control, you should hear MF sound from the
MF speakers.
29. Press down all the mute switches of PCR2213 and release the LF mute switch.
30. Turn on the LF power amplifier with input level at minimum.
31. Slowly turn up the level control of the LF power amplifier, you should hear strong LF sound from the LF
speakers.
32. Un-mute the HF and MF, and turn up the level until the LF, MF and HF are about balanced.
33. Turn up HF, MF and LF levels until the sound pressure level reached 10dB below designed operating
level. (If you set the operating at 90dB, you shall reach 80dB. If you set the operating at 100dB, you shall
reach 90dB, so on and so forth Our recommendation is 0VU at 90dB SPL for most of the application.)
34. Press down the low cut if you’re using vented LF speaker which doesn’t extend to 30Hz or lower.
35. Press down the Horn EQ if you’re using HF horn which is constant directivity design.
36. Refer to 5.5 for limiter adjustment.
37. Fine tune the system with the steps instructed by the test instrument you are using. Please note the delay
time can also be fine tuned with precision instrument such as ETF or TEF which include time domain
measurement.
*(Delay adjustment based on the HF diaphragm is the farthest, and MF is farther than LF. If this is not the case,
and MF is the farthest, refer the LF delay time from MF, and HF may need additional time delay unit to
compensate the offset.)
5.4 DELAY TIME
The speed of sound is affected by air temperature. You can calculate the sound speed as following:
C
= 49 * (459.4 + °F)
1/2
in feet per second.
C
= 20.6 * (273 + °C)
1/2
in meter per second.
Where
C
is the speed of sound.
To compensate the offset between the speakers, the time will equal to the distance divided by speed.
T = D/
C
Where T is the delay time in second, and D as distance in meter or feet between the speakers.
The maximum delay time is 4 msec, which equal to 1.42 meters at 25°C or 4.52 feet at 72°F. This distance is
sufficient for most speaker installation except those separating the speaker cabinet far apart. The very large
long throw horns usually measure at 1.2 meters. If you have any huge horn to work with direct radiate bass
unit, it is a good idea to move the bass a little back than the horn mouth. Keep the speaker driver distance
within 1.4 meter will be fine for PCR2213.
If you want to make a precise delay time adjustment, connect the PCR2213 with dual channel oscilloscope with
PCR2213 input signal measured by one oscilloscope channel and LF output to the other channel. Send the
sine wave into PCR2213 and adjust the delay time until the horizontal time offset equal to your design.
5.5 LIMITER SETTING
1. To properly set the limiter threshold. You need to find out the capacity of the speaker and associated
amplifier. Because the threshold is global setting, we shall make use of the level control on the PCR2213
as well as those on the power amplifiers, so that it works with all bands.
2. Disconnect one set of the speakers and hook up dummy loads (same value as the speaker loading) to
the amplifiers (You can connect only one output of the amplifier if you have multiple for the same band,
and turn them off without removing the speaker connection.