Question about Graphic EQ

[Benjamin]

Hello

My church has run into a little problem with installing a graphic EQ. Our current sound system is hooked up mono, and we have a DBX 321 31 band stereo EQ we want to add to our system. We have a Mackie SR 24-4 mixing console. I read in the user manual that you would hook up the EQ in the "main outs". But the problem is that on the main outs it says Left and Right, and on the back of our EQ it says Input and Output. I do understand that we only need to plug in one channel of the EQ due to the fact we are running a mono system.

What is the proper way on hooking this EQ up? I hope i provided enough information!

Please, any help is appreciated! We really want this EQ hooked up!

[waynehoskins]

Perhaps it's a dbx 231?

Generally you would connect the main console outputs to the inputs of the EQ, and plug whatever was in the console outputs before to the EQ outputs.

If your system is mono but you're taking stereo output from the console, at some point downstream there must be only one signal. This could be from either combining L and R to mono through a Y, either passive or resistive, through an active device like a system processor. or even by simply discarding one of the signals. If there's a monoing network or a Y-cable, it would make sense to put that before the EQ. If there's a system processor, it would be more beneficial to adjust that. If only one side of the console output is being used, perhaps it would be better to take output from a Mono Output if the console has one.

[Brad Weber]

We almost need to start by saying there are a myriad of ways to connect the equalizer depending on what you are trying to do. The following assumed that you are simply trying to put it in line after the mixer for the main audio feed for the house systems.

Your mixer has five 'Main Outs'. There is both an XLR and a balanced 1/4" TRS connection labeled Left and another set labeled Right. The fifth output is a Mono output that is an XLR connector and that also has a separate volume control that affects it located on the rear panel. Since you have a mono system you are likely using the Mono output, although it could also be using either of the left or right outputs depending on how the system is configured.

The equalizer, which I assume is actually a dbx 231, is a two channel device. If you have a mono system you will typically use only one of the channels. The 231 also has both XLR and balanced 1/4" TRS connections for input and output on both channels.

What you will probably want to do is unplug whatever Main Out connection is currently used at the Mackie mixer and connect that to the Channel 1 output connection, either 1/4" or XLR, of the dbx 231. You will then need a new cable between where the cable you just moved was previously connected on the Mackie mixer and either the XLR or 1/4" TRS connector on the Channel 1 Input of the dbx 231. So it will be a new cable from the Mackie Main Out (whichever one is currently used) to dbx 231 Channel 1 In and then the existing cable from the dbx equalizer Channel 1 out to rest of the sound system.

[Live4the1]

Not wanting to hi-jack this thread but what about on the flip side of that? We have a mono send to the eq but at some point we may want to change to a stereo feed. Do you just use two single channel or one dual channel eq and set both the same or are there dual channel eq's that have a stereo couple switch like many compressors do?

[Brad Weber]

Originally Posted by Live4the1

Not wanting to hi-jack this thread but what about on the flip side of that? We have a mono send to the eq but at some point we may want to change to a stereo feed. Do you just use two single channel or one dual channel eq and set both the same or are there dual channel eq's that have a stereo couple switch like many compressors do?

Are they really the same? If you have a perfectly symmetrical room and system including in regards to room finishes and the listener area, then the EQ would likely be the same for both channels, but many times there may be differences between the two channels.

There are some two channel EQs that use one set of controls and apply that to both channels but the more common approach is a two channel device and starting with identical settings for each channel, then making and adjustments necessary to the individual channels.