Proel PC260 - Manual (Page 28)

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RTA
The PC260 processor has a built in 1/3 octave Real Time Analyzer, which is a useful tool for measuring the acoustic response of the
sound system in order to make the proper EQ adjustments .
This RTA is not a precise measurement system such as dedicated computer software, but it can be used to get a general overview of
the system's response in a not too much reverberant and noisy enviroment .
When you use an acoustic measurement gear remember always the following tips:
• You have to fix the system not a line on the screen.
• With the equalization you cannot correct a bad room acoustic: if the venue is too reverberant at some frequencies it remains
reverberant also after the equalization .
• Always listen with your hear, do not blindfold trust any measurement.
• A good audio system placed in a good enviroment requires only little adjustments, usually by cutting few dBs in some frequency
ranges . If you have to set exaggerated EQ, you probably have a noticeable acoustic problem and EQ'ing could not be the right cure .
• Acoustics measurements are not a simple issue and require a specific knowledge.
To make a RTA measurement you must have some additional equipment:
• A measurement microphone: for this kind of measurement you don't need the best microphone avilable, a simple and economic
class 2 microphone is sufficient .
• A microphone stand.
• A XLR balanced cable (the lenght depends by the distance between the measurement mic and the PC260).
• A track with a pink noise record: pink noise is a special random noise where each octave carries an equal amount of noise power.
• A track or a selection of tracks of your preferred songs.
Connect the mic to the RTA MIC INPUT then place the mic on the stand at the centre of the venue . The distance between the speakers
and the measurement mic must be no longer than 10 meters (30 ft), otherwise you may not have a sufficient signal to noise ratio .
1) Play the pink noise on the audio system .
2) Turn up the volume to a reasonable level, avoiding to compress/limit any input/output in the PC260 (see the LED
indicators on the front panel) .
3) Press RTA, then using the DIAL knob adjust the mic input level to have a sufficient signal across the mid line . If the
audio system is right tuned, the RTA is aproximately linear with some bars above and some bars below the mid line .
4) If a noticeable misalignment is displayed you can try to adjust it using the input GEQ or PEQ .
5) After some adjustments you may be obtain a more linear RTA .
Often if the misalignement is under the 400 Hz and you cannot obtain any
adjustment, try to move the MIC in another position .
6) Once you are satisfied, turn off the pink noise and play you favorite songs .
By turning on and off the EQ section, listen the differences and if necessary
adjust the EQ settings . Always remember the first tip:
You have to fix the system not a line on the screen.
BEFORE EQ'ING
AFTER EQ'ING