question on how to properly wire this system

NickfromSOS · #1 08-01-2011, 08:59 PM

I have the following set up:

2- Peavey PR12 speakers
2- EV SB122 subs
1- QSC PLX3002 amp
1- active crossover

the EV subs have built in hi pass filters set at 160hz. Way to high. I'd like to use one side of the amp to run the tops and one side to run the subs but how can I bypass the internal crossover of the sub? As far as I see it, if I try to daisy chain the 2 together, the 2nd sub is going to get a signal at 160hz and above since the first sub will be crossing over the signal. Can I disable the internal crossover?

testing1two · #2 08-01-2011, 11:32 PM

The low pass filter in the subs isn't an issue since you have an external x-over. Take the main output signal from your mixer into the x-over. Take the low output from the x-over and put it into one channel of your amp and take the high output from the x-over and put it into the second channel of your amp (the amp should be set for full range stereo operation). Then take the low output of the amp and run it to the first sub and daisy chain the second sub. Take the high output of the amp and run it to the first PR12 and daisy chain the second. Then balance the low and high output using the controls on the x-over. This is also the time to play with the x-over frequency.

Since you are using an external x-over the low pass filter in the subs won't come into play b/c you aren't sending them anything upwards of 160Hz.

NickfromSOS · #3 08-02-2011, 06:26 AM

Thanks for the reply... But it is my understanding that the "out" jack on the sub is already filtered so that the signal coming out is 160hz and above. It doesn't not send a full signal so the 2nd sub would not receive a full range signal

WayneP · #4 08-02-2011, 07:49 AM

In that case you can just run two speaker cables from the amp - one to each sub.

Regards,
Wayne A. Pflughaupt

testing1two · #5 08-02-2011, 02:49 PM

Quote:

Originally Posted by NickfromSOS

Thanks for the reply... But it is my understanding that the "out" jack on the sub is already filtered so that the signal coming out is 160hz and above. It doesn't not send a full signal so the 2nd sub would not receive a full range signal

Actually you are misunderstanding the difference between Low Pass Filter (LPF) and Crossover. Your sub has a built in LPF so you can feed the sub a full range signal (in case you don't have an external crossover) and it will filter out everything above 160Hz. It does not pass anything above 160Hz at all. A crossover on the other hand divides the signal into two bands which are separated at the crossover frequency.

Also, the speaker jacks on the back of the sub are in parallel which means the signal is divided before the LPF. So that means if you daisy chain your subs without a crossover both will filter out anything above 160Hz, or you can use your crossover and both subs will see the same signal based on your designated crossover frequency.

http://www.electrovoice.com/sitefile.../SB122_EDS.pdf

Doctor Dirt · #6 08-02-2011, 03:05 PM

Set your outboard x/overs settings if your under feeding speakers and sart to push them your looking for troubles. Doc at 120 to be safe and for starters but to be honest with you hopefully your subs are 8ohm then daisy them to a 4ohm load so your getting the most out of your ch.1 on the amp. What kind of subs are they and is your amp feeding them what they need? Thats actually the first thing you need to know before going into x.overs. Does your power amp offer your cabs what they need power wise? Doc

NickfromSOS · #7 08-02-2011, 04:20 PM

Subs are 400 watts each at 8 ohms. The qsc puts out 900 at 4 ohms per side. I called ev today and they said that daisy chaining the subs is fine

TimmyP · #8 08-03-2011, 12:10 AM

A crossover is (in basic form) nothing more than a collection of high pass and low pass filters. Each filter is separate from the others (though they may be in series, such as the high pass and low pass for a loudspeaker's midrange section).

WayneP · #9 08-03-2011, 08:12 AM

Quote:

Originally Posted by TimmyP

A crossover is (in basic form) nothing more than a collection of high pass and low pass filters. Each filter is separate from the others (though they may be in series, such as the high pass and low pass for a loudspeaker's midrange section).

That would be a bandpass filter.

Regards,
Wayne A. Pflughaupt