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Auto Eq DRPA/DRPA+/PX Why, How, and Where...
Some of this is covered in other threads...please bear with me...This is a new thread, 1st quarter 2012.
First thing, lets look at the input meters, they are good for basically one thing, showing signal, and showing peak/clip. They are inaccurate, and misleading...( ALMOST every meter IS...) If you set the xover gains at unity, 1 volt in = 1 volt out of the DRPA/PX, DRPA+ (with the switch in the back in the +4 dB position...If memory serves) Why do I bring this up? Well, if your sending anything LESS than full output potential from your PRO level mixer ( greater than +22dB) you will notice that the input meters read what seems to be VERY LOW...this is NOT a problem, however, clipping IS! If you have a good gain structure on the input channels (like you should) then with the master faders sitting at unity you will only be feeding the driverack a signal strong enough to tickle the first couple bars..because -0-dB input meter on the driverack is +22dB! So, that said if your sending an average -0- signals from the channels on the mixer, and a -0- dB signal out of the mixer (meters reading -0- average... the input meters on the DRPA would need to be showing about -22dB... so, only the first 2 LED's would flicker for a -0- dB signal from the mixer...
Note that the measurement mic is routed to the DRPA/PX, DRPA+ input when the auto EQ process is started, and, that once the CLIP level is met, the DRPA+ will tell you to turn DOWN the level. (this is so the inputs aren't clipping...) to get MORE loudness for the process, you will need to move the speakers AWAY from the measurement mic...the farther the speakers are away, the louder they will HAVE to be to meet the measurement requirements... so, lets say you wish to run 105dB 'C' weighted, engage the Auto, set for flat and medium or high sensitivity (DRPA+) or LOW DRPA/PX (because it would take FOREVER to finish)...using a Decibel meter set the speaker output @ 105dB at the point you want that level (3 feet is pretty useless lets say 10 feet minimum) now move the speaker back (or measurement mic) till you are within the -0- dB area )or slightly below. Now if you take your measurement you should have no trouble with the "TURN DOWN" notification. You will also be measuring the speakers response AT THE LEVEL THEY WILL BE PLAYING... and believe me the loudness makes a BIG difference in the way a speaker sounds... especially when you PUSH IT!
And, I don't care WHAT the manual says...Putting the mic on a stand between the speakers 20-25 feet out is a recipe for DISASTROUS sound! One speaker at time (on a stand if possible, note: look up free space measurements, and 1/4, 1/2, and 3/4 for understanding why...) mic strait out, 25 feet is best (or so) mic on the ground, on a soft surface (towel, carpet etc.) aimed at the speaker...
A second off axis measurement should also be taken and averaged for best sound (with your ears) between the two measurements. So if on axis you had a 3dB boost @ 3.15khz and the off axis was 3dB cut, see if an average of -0-dB wouldn't make both places sound better...
Outdoor freefield measurements mic on a stand are possible, indoors not so much...
Be forewarned about LF modes and standing waves that will artificially lower the bass level when using the Auto EQ indoors...Below about 170 hz the room will start to build up bass... and the auto EQ will start to cut it... FYI about the only place in the room the measurement mic would not be affected by this is is the corners...where 3 walls come together.
This region should be done by ear. Know that when speakers are placed against a boundary, like the floor you WILL get a 3dB boost for each boundary, but you will also get an unreasonable boost at certain frequencies. 60, 100, and 160/170 hz area's are prime locations for filters (PEQ's) to help deal with these...(but NOT limited to them...)
Be aware of the rules of placement, Against the wall or more than 8 feet out.
Lots more info in the "Start Here" on gain structure and setup, and More in depth stuff here in the "FAQ" section.
Gadget
First thing, lets look at the input meters, they are good for basically one thing, showing signal, and showing peak/clip. They are inaccurate, and misleading...( ALMOST every meter IS...) If you set the xover gains at unity, 1 volt in = 1 volt out of the DRPA/PX, DRPA+ (with the switch in the back in the +4 dB position...If memory serves) Why do I bring this up? Well, if your sending anything LESS than full output potential from your PRO level mixer ( greater than +22dB) you will notice that the input meters read what seems to be VERY LOW...this is NOT a problem, however, clipping IS! If you have a good gain structure on the input channels (like you should) then with the master faders sitting at unity you will only be feeding the driverack a signal strong enough to tickle the first couple bars..because -0-dB input meter on the driverack is +22dB! So, that said if your sending an average -0- signals from the channels on the mixer, and a -0- dB signal out of the mixer (meters reading -0- average... the input meters on the DRPA would need to be showing about -22dB... so, only the first 2 LED's would flicker for a -0- dB signal from the mixer...
Note that the measurement mic is routed to the DRPA/PX, DRPA+ input when the auto EQ process is started, and, that once the CLIP level is met, the DRPA+ will tell you to turn DOWN the level. (this is so the inputs aren't clipping...) to get MORE loudness for the process, you will need to move the speakers AWAY from the measurement mic...the farther the speakers are away, the louder they will HAVE to be to meet the measurement requirements... so, lets say you wish to run 105dB 'C' weighted, engage the Auto, set for flat and medium or high sensitivity (DRPA+) or LOW DRPA/PX (because it would take FOREVER to finish)...using a Decibel meter set the speaker output @ 105dB at the point you want that level (3 feet is pretty useless lets say 10 feet minimum) now move the speaker back (or measurement mic) till you are within the -0- dB area )or slightly below. Now if you take your measurement you should have no trouble with the "TURN DOWN" notification. You will also be measuring the speakers response AT THE LEVEL THEY WILL BE PLAYING... and believe me the loudness makes a BIG difference in the way a speaker sounds... especially when you PUSH IT!
And, I don't care WHAT the manual says...Putting the mic on a stand between the speakers 20-25 feet out is a recipe for DISASTROUS sound! One speaker at time (on a stand if possible, note: look up free space measurements, and 1/4, 1/2, and 3/4 for understanding why...) mic strait out, 25 feet is best (or so) mic on the ground, on a soft surface (towel, carpet etc.) aimed at the speaker...
A second off axis measurement should also be taken and averaged for best sound (with your ears) between the two measurements. So if on axis you had a 3dB boost @ 3.15khz and the off axis was 3dB cut, see if an average of -0-dB wouldn't make both places sound better...
Outdoor freefield measurements mic on a stand are possible, indoors not so much...
Be forewarned about LF modes and standing waves that will artificially lower the bass level when using the Auto EQ indoors...Below about 170 hz the room will start to build up bass... and the auto EQ will start to cut it... FYI about the only place in the room the measurement mic would not be affected by this is is the corners...where 3 walls come together.
This region should be done by ear. Know that when speakers are placed against a boundary, like the floor you WILL get a 3dB boost for each boundary, but you will also get an unreasonable boost at certain frequencies. 60, 100, and 160/170 hz area's are prime locations for filters (PEQ's) to help deal with these...(but NOT limited to them...)
Be aware of the rules of placement, Against the wall or more than 8 feet out.
Lots more info in the "Start Here" on gain structure and setup, and More in depth stuff here in the "FAQ" section.
Gadget
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