Adding sub screwed my stereo imaging. Please help...

[cjthibeault]

Hello Everyone,

I've had two KRK RP-8s for a while, and decided to add in the subwoofer (the RP-10S). Originally, my stereo imaging was perfect. If something was supposed to be in the center, it was absolutely centered. Now, my center is all over the place.

The two monitors are each on their own set of mopads and marble. The sub is on an Auralex SubDude. Room is treated with Auralex and mineral fiber bass traps in three corners.

As for positioning, My desk is set up in a corner. I face into the corner. My monitors are on the side walls, facing directly at me. So my monitors, me, and the corner form a square if you were to draw it. The sub is on the floor, with the cone pretty close to centered between the monitors, but at a sharp angle (due to the desk support beams).

Since adding the sub, my stereo imaging in the main monitors has gone way off. Even if I am playing tones that the sub doesn't touch (A440 for example). I've had to turn down my right monitor's input volume about 6 notches. That gets it roughly centered, but it still sounds very 'spread' and 'unfocused'. It used to have a pin-point accurate center.

Anyone have any ideas what is going on, and what should I do? This is absolutely driving me crazy. I just want my center back Any help would be greatly appreciated.

Thanks,
Chris

 

[lumbago]

Check with headphones only. Unplug the speakers

Is the headphones output same level on left and right? If not - check your pad switches at input, your 10dB/4dB switches and all leads.

Now reverse the headphones L-R.

If the imbalance is still leaning to the SAME side, have your ears checked.
If the imbalance is leaning to the opposite side, there's problem somewhere else in your electronics.

Go back to using the self powered monitors.
Swap their locations.

If the balance problem stays the same, there's a problem in the room (standing waves / phase issues at Low Frequency), otherwise it's in your electronics somewhere.

There could be a phase reversal in one of your leads. That would explain why the spread sounds wrong.

You might also try the speakers in another room from a different source (cassette deck, say). Check that you haven't blown one.

 

[scrubs]

I would get yourself out of the corner. I don't care how good it sounded before, corners are generally terrible for mixing, as peaks/nulls tend to concentrate there. Adding a sub is only going to accentuate the bass problems of mixing in a corner. YMMV.

 

[mrface2112]

+1 to what scrubs said. what you're hearing is a problem with your room.


cheers,
wade

 

[MadMax]

I could also be your crossover point. If it's too high, you'll have some of your program material going thru the sub and that can obviously mess with your imaging.

 

[MadAudio]

Also make sure all you cables are good - they are usually the weakest link.

 

[cjthibeault]

Hello,

Thanks for the tips, but I think many of you missed some of the things I said. It isn't a matter of crossover freq or room treatment. I'm testing this with straight tones (440hz, and others). Tones high enough to not have any subwoofer interaction at all. So this is just coming out of the mains. Mains that, in the same room with the same acoustic treatment, were previously dead centered imaging-wise.

The cable thing is a good point. Previously, everything was good quality, balanced cabling. When hooking things up today, I realized that I had bought a wrong cord (m instead of f), so I used an XLR-to-TS unbalanced cable instead of the XLR-to-TRS balanced I would have preferred. I can't believe it would make that much of a difference, but I'll be swapping it out soon.

Yeah, I know the corner sucks. But I've learned to deal with it. It is mostly for listening, and some rare mixing when I actually take time from work to do some recording (this room is primarily my home office, which has been acoustically treated and rigged for good listening while I work).

Anyway, if anyone has anything else, let me know. Thanks again for the tips.

-Chris

 

[MadAudio]

Yeah, I know the corner sucks.

Then you are willfully disregadring common practice and common sense about your monitoring environment. There's no way your mixes are going to translate into other environments properly if you're judging them solely by that set up.

 

[Farview]

Hello,

The cable thing is a good point. Previously, everything was good quality, balanced cabling. When hooking things up today, I realized that I had bought a wrong cord (m instead of f), so I used an XLR-to-TS unbalanced cable instead of the XLR-to-TRS balanced I would have preferred. I can't believe it would make that much of a difference, but I'll be swapping it out soon.

-Chris

That could easily be your problem. At the very least, you will lose 6db because you unbalanced the signal. At worst, one of the speakers is out of phase due to the wiring.

 

[cjthibeault]

Hi,

Farview, I didn't realize that about the unbalanced cable. That is probably the answer to my problems. Thanks!

MadAudio,

> common practice

Yes, I am disregarding that. Though I am aware of it.

> common sense

This is where I disagree. As I said, this is primarily my home office. I do computer work here. I like to listen to music while I work. I do some recording in my spare time. I do what I can with what I have. My room is a 12x12 (which I know really sucks). Space is limited. My corner desk works out best for me. I know my monitoring is going to suffer. But I've learned to deal with it. If I really wanted to sacrifice everything for the best possible monitoring, I wouldn't be monitoring with KRK RP-8s in a 12x12, now would I?

Common sense is doing what makes the most sense for the purposes that I want to achieve. The world's perfect monitoring environment isn't what I'm looking for. I'm looking for good enough, and I was pretty close before I added the sub. Hopefully a new cable will fix that...

Thanks again,
-Chris

 

[cjthibeault]

One more thing farview,

Out-of-phase would describe it very well. It has a bit of that 'something isn't right in the middle of my head' feeling to it.

Thanks,
-Chris

 

[cjthibeault]

FOLLOW UP:

Yup. It was the cable. I have another of the unbalanced ones here, so I swapped it out in the monitor that had the balanced XLR/TRS cable. Problem fixed. So all I need is another cable.

Thanks,
-Chris