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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Lounge => Topic started by: Chris Delcambre on April 13, 2011, 07:15:21 PM
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Hi guys,
I have some XTI4000's I have bridged for my subs and lows on my system (4-Peavey QW218 and 4-Peavey QW4). I am showing level on both input meters when bridged but only have an input connected to input 1. My question is why and do both of the front panel input att. need to be turned up??? The amps are set bridged and the input setup is stereo not y or summed. It just doesnt seem like I am getting the power I was expecting to get. I have the input of my speaker connected to the middle 2 banana terminals on the XTI4000.
Thanks for any help you can provide.
Chris
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Hi guys,
I have some XTI4000's I have bridged for my subs and lows on my system (4-Peavey QW218 and 4-Peavey QW4). I am showing level on both input meters when bridged but only have an input connected to input 1. My question is why and do both of the front panel input att. need to be turned up??? The amps are set bridged and the input setup is stereo not y or summed. It just doesnt seem like I am getting the power I was expecting to get. I have the input of my speaker connected to the middle 2 banana terminals on the XTI4000.
Thanks for any help you can provide.
Chris
The LED meters on the XTi are a combination of "input present" and output level meters. It's appropriate that you see both channel meters functioning.
Did you read the manual? All your questions can be answered with some careful study and consideration of Crown's words. Pages 13, 17 and 22-26. Pay particular attention to the "Y" mode and BRG mode. Note that the BRG *preset* is implemented differently that the default bridged mode settings.
Have fun, happy reading.
Tim Mc
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when you bridge a stereo or 2 channel amp channel A becomes the + side and channel B becomes the - side. both gains need to be set the same so that your putting equal voltage to the speaker. example channel A>50 volts , channel B>50 volts. both level indiactors are going to be showing the gain level because both channel are driving the speaker. its the same principle of a clothes dryer that opperates on 220 volts ac. one leg is 180deg opposite on the 60cps leg from the other one. one leg to ground(neutral) is 120 volts. the same principle applies to an audio amplifier. the audio amplifier drives the speaker with ac current. if your gain controls have detents turn to zero and count an equal amount of detents for each channel if they are not set to max.
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when you bridge a stereo or 2 channel amp channel A becomes the + side and channel B becomes the - side. both gains need to be set the same so that your putting equal voltage to the speaker. if your gain controls have detents turn to zero and count an equal amount of detents for each channel if they are not set to max.
You really should read the manual before offering advice on any topic.
From the XTI manual:
pg 25: CH1+CH2 (Ch.1 input signal and Ch. 2 input signal are
summed and fed to both output channels.) This provides a
6 dB level boost.
• INPUT Y (Ch. 1 input signal goes to Ch. 1 and Ch. 2
output. Ch. 2 input signal is ignored.)
pg 26: BRG (Bridge-mono or Stereo): Use this option to set
the amplifi er to bridge-mono or stereo mode. When BRIDGE
is active, the Ch. 1 input signal is used (unless you made an
alternate setting with the Y processing block).
gp
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when you bridge a stereo or 2 channel amp channel A becomes the + side and channel B becomes the - side. both gains need to be set the same so that your putting equal voltage to the speaker. if your gain controls have detents turn to zero and count an equal amount of detents for each channel if they are not set to max.
You really should read the manual before offering advice on any topic.
From the XTI manual:
pg 25: CH1+CH2 (Ch.1 input signal and Ch. 2 input signal are
summed and fed to both output channels.) This provides a
6 dB level boost.
• INPUT Y (Ch. 1 input signal goes to Ch. 1 and Ch. 2
output. Ch. 2 input signal is ignored.)
pg 26: BRG (Bridge-mono or Stereo): Use this option to set
the amplifi er to bridge-mono or stereo mode. When BRIDGE
is active, the Ch. 1 input signal is used (unless you made an
alternate setting with the Y processing block).
gp
if your refering to me you should read what i posted agian. i went into a little detail about what bridging is and how it works and the reason BOTH channel lights/meters will be lighting/moving and why both gain controls should be set at the same level in bridged mono operation. my adivice is sound and accurate advice.
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my adivice is sound and accurate advice.
Except for the bit about ch 2. The instructions clearly say only ch 1 is used.
Mac
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my adivice is sound and accurate advice.
Except for the bit about ch 2. The instructions clearly say only ch 1 is used.
Mac
in my original reply i never said which channel to connect the input signal to. i was only stating the reason both meters work and why both gains need to be set the same when operating in bridged mono. as for which channel to connect the input to you would refer to the manual cause not all manufacturers use the same channel. my qsc amps use channel 2 for the input when bridged but that was not what my original reply was about. i was simply explaing that channel A and B are driven 180 deg opposite of each other so they produce ac current in bridged operation. if they were both driven in phase with each other it wouldnt work.
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Hi guys,
I am showing level on both input meters when bridged but only have an input connected to input 1. >>>""""My question is why and do both of the front panel input att. need to be turned up??? """"" <<<
this is what i was refering to in my first reply for those who didnt understand what i said.
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this is what i was refering to in my first reply for those who didnt understand what i said.
From the manual -
NOTE: In Bridge-Mono mode, only the Channel 1 level control is functional.
This is not the only model or manufacturer that does this. The channel 2 level control can be set at 0 or at max - it doesn't matter.
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From the manual -
NOTE: In Bridge-Mono mode, only the Channel 1 level control is functional.
This is not the only model or manufacturer that does this. The channel 2 level control can be set at 0 or at max - it doesn't matter.
Uh, sort of. From page 26...
BRG (Bridge-mono or Stereo): Use this option to set
the amplifi er to bridge-mono or stereo mode. When BRIDGE
is active, the Ch. 1 input signal is used (unless you made an
alternate setting with the Y processing block).
From page 25...
Y (Input Y): The options are
• CH1+CH2 (Ch.1 input signal and Ch. 2 input signal are
summed and fed to both output channels.) This provides a
6 dB level boost.
• INPUT Y (Ch. 1 input signal goes to Ch. 1 and Ch. 2
output. Ch. 2 input signal is ignored.)
• STEREO (Ch. 1 input goes to Ch. 1 output. Ch. 2 input
goes to Ch. 2 output.)
The way it defaults is this: blank preset, starting from scratch and going into OUTPUT BRG mode, the "Y" setting is stereo input; channel 2 physical input is ignored and external level knob is bypassed. This is how the "Y" option works, too. Only Channel 1 input and output processing is accessible but is applied internally to both channels.
Changing the "Y" selection changes the behavior of the Channel 2 external level knob and physical input. If you use the sum (A+B) input mode the physical connection and knob now work, but the input and output processing is still "one channel."
Crown doesn't put the puzzle together, but they at least provide all the pieces.
Have fun, good luck.
Tim Mc
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this is what i was refering to in my first reply for those who didnt understand what i said.
From the manual -
NOTE: In Bridge-Mono mode, only the Channel 1 level control is functional.
This is not the only model or manufacturer that does this. The channel 2 level control can be set at 0 or at max - it doesn't matter.
ok , my bag , i havent used amps where that was the case.
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Okay, so I searched through the threads here to try and answer my question before coming to you guys. This was as close as I could come, so if you can just clarify my questions/answers within the quote, in bold, that would be great! Thanks!
I'm planning on running xti4000s bridged, one per sub. And xti2000s bridged, one per mid.
You really should read the manual before offering advice on any topic.
From the XTI manual:
pg 25: CH1+CH2 (Ch.1 input signal and Ch. 2 input signal are
summed and fed to both output channels.) This provides a
6 dB level boost.
If I go this route, I get 6 db of boost. Both output channels are hot, and both level controls will be used? Do I also have to plug into both inputs? So if I plug either (1) 4 ohm load into either output A or B, I'll get the same as if I plug an 8 ohm load into output A and B separately? Is there any other purpose for running it this way other than the 6 dB boost?
• INPUT Y (Ch. 1 input signal goes to Ch. 1 and Ch. 2
output. Ch. 2 input signal is ignored.)
This is the usual way most older amps were run bridge mono? Input into Channel One, Output from channel One? Channel Two is not used at either input as stated above or output?
pg 26: BRG (Bridge-mono or Stereo): Use this option to set
the amplifi er to bridge-mono or stereo mode. When BRIDGE
is active, the Ch. 1 input signal is used (unless you made an
alternate setting with the Y processing block).
In this BRIDGE setting, they are using the Input Y setting as described above, unless you change it as they say in the processing block?
gp
Input Y would be the logical/simplest way to go when bridging one amp to one speaker? At the current time, I won't be using any of the other onboard processing.
Thanks!