What is wrong with this graphic EQ??

What is wrong with this graphic EQ??

Hey guys,

Normally this stuff doesn’t present a problem for me, but I’ve run into a situation that has me pulling my hair out looking for an answer. I am slowly building a home studio/production station, and wanted to add an old DBX 31-band graphic EQ in between my computer and my home stereo I’m using as a monitoring system right now. I have a 1/8in stereo cable going from the computer into the TRS input of the EQ with a 1/8in-1/4in headphone adapter jack on the end. It’s the same situation with the output. I thought initially that maybe I had a bad cable or a bad adapter and swapped both of those out. No change. It outputs sound, but it is only outputting to the left speaker in a mono signal. Doing a stereo test confirmed that it is only recognizing one speaker. The EQ is a DBX 131 model. I’m confused as to why it’s putting out a mono signal when it has TRS (stereo) inputs and outputs. What am I doing wrong? It does this on both the computer and a standard mp3 player. I’m beginning to wonder if perhaps one of the jacks on the EQ has a channel busted.

It’s outputting a mono signal because it’s a mono EQ. A 1/4" jack does not always equal stereo. Also that cable setup is going to give you trouble in the future, I’d suggest expanding your sound engineering knowledge a bit before investing in equipment.

Model 131 description copied from the dbx website, 131 | dbx Professional Audio | English (US) “Single Channel 31-Band Graphic Equalizer”

The first step of building anything is knowing what you bought to start with.

One trip in the Google magical search engine ride would’ve earned you +10 internets. Now you lose 50 internets due to not googling before asking.

I understand it’s a mono signal, but I don’t understand why it’s still only outputting to the left. If it was a mono signal, wouldn’t it just be putting out the same output to each speaker? This is what confuses me the most, because when it was originally setup in my mobile rig, it was sending a mono signal to each speaker (it was a stereo power amp too). Also, why would you include TRS inputs if it was outputting a mono signal? I know this isn’t an ideal setup, I’m using this to hold me over until i’m no longer so strapped for cash; a “leftover gear” sandwich if you will :smiley:

Professional gear uses balanced connections, ie, tip, ring sleeve or XLR. You may want to do as Shishdisma says and research audio because from the sound of some of your statements you might just blow something up or shock yourself. There’s some great books out there about audio reinforcement, cabling and such or just use the internets.

Notice the difference between the grey and red headed cabels here (two mono inputs) and the black with the extra ring it (stereo). If you want the former you will need one of these

@ Nicky, it’s still not going to matter because the eq he has is a mono eq, for one channel only.

Tha’s why I’m saying homie needs a splitter if he wants mono 1/4" to stereo
The whole thing is probably a bad idea if we’re talking production but thats just IMO

The generally accepted term (in my experience) is a Y cable. Going back with a practical example of what I said earlier about learning: any kind of setup involving a stereo-mono-split mono setup typically requires summing. Under no circumstances should you ever sum with a Y cable. Use a summing/DI box/mixer, or mono the sound output in software. You WILL fry your shit if you use a TS Y cable backwards.

Here’s some reading if you want details about why to avoid the Y: http://www.rane.com/note109.html

If you need to go stereo to mono, something like this is necessary: Amazon.com: Rapco Horizon TDIBLOX Tape Deck Interface Device : Musical Instruments

Something like this would probably do the trick too, and give you more options - Amazon.com: Galaxy JIB/R RCA Combiner : Electronics

The fact that the OP even requires an adapter is the real issue here. Obviously the money spent on an EQ and all the required adapters should have been put towards getting a proper audio interface with either balanced 1/4 or XLR outputs.

/thread