High pitched noise in my monitors...Computer issue?

[eanderso13]

Hey everyone, I've got a question for those of you with more experience than me in setting up studios and such. here is my setup:

-Mac PPC G4 at about 1.4 GHz
-Protools LE with MBox 2
-Alesis M1 Active monitors (old...like from 200o or so)
-Big, honking CRT monitor
-External Firewire harddrive

My issue? When I start the computer up and turn the speakers on I can hear a not-so faint high-pitched whine. Once I start Protools it gets worse. And when I run a mic through a preamp and into the MBox, it usually gets even worse still!

I have a relatively small room, and the stuff is sort of in a corner. Think, main desk and monitors and such on one wall, rack of a few preamps and compressors and the MBox on the wall to my right and the Mac sitting on the floor in the corner between the two. the harddrive is sitting on top of one of the monitors.

any thoughts on what could be inducing that noise in the speakers and on the input lines? I can't really tell is the sound is getting recorded, since its in the speakers anyway, but I'm pretty sure it is appearing at least somewhat on the recorded tracks. Is the computer too close to everything and inducing noise in the wires connecting everything? Are the monitors possible old and bad and succeptable to some sort of interference (not shielded well?)

Any advice would be greatly appreciated, as it is annoying to try and record and mix with this noise.

Thanks.

-Eric

[fierylungs]

My first thought would be to check all your audio cables to make sure they aren't running next to any power/data (monitor included) cables. I know the pain of a tight setup so if any audio cables have to cross a power/data cable be sure they do so at right angles.

AFA whether or not the noise is being recorded; could you do a test burn and check?

Another idea would be to get a battery backup. In addition to being able to save your work in the case of a power outage, you also get much cleaner power. I'm still blown away by the difference it made in my modest setup.

[Dakota]

MBox

You may have the dreaded mbox whine. Google mbox +whine, or variations on that. It's a common issue.

Pull the mbox out of the equation, troubleshoot. Try the standard audio outs from your mac straight to the speakers, rig for comparable volume. Did the whine go away?

An "ultimate performance" usb cable from monster will sometimes fix the issue (better grounding, or so it is claimed). Sometimes not. Other makes of premium or highest end usb cables are sometimes reported as fixing it as well.

Digi acknowledges that some people have a whine issue, but won't admit it's a design flaw.

[eanderso13]

Iiiinteresting:shock: ....I had not heard about this. I'll look into it. Thanks for the tips so far, guys!

[eanderso13]

Well, I went home, dug out a couple in-line isolation transformers, wired up two male-male XLR cables and plugged those into the MBox and the monitors *POOF* no more high-pitched noise! Even when I start ProTools up! I was amazed at how much information was out there about this MBox Whine issue and how many different fixes there were that worked for some people but not others.

When I plug some outboard gear into the MBox inputs I still get a bit of whine, so I'm guess that has to do with ground loops or something of that nature. So I'll try a Monster Clean Power surge protector or something next and see what I get.

But thanks so much for the advice!

-Eric

[@?,*???&?]

The computer generates a fair amount of RF. I've typically gotten rid of this either ground lifting the monitors or running balanced cable to the monitors from the audio interface.

Sometimes, isolating power strips gets rid of the problem, in other words, run your computer off a different strip than your monitors.

Better still, run them off different circuits.

RF is nasty. Unbalanced cables are nasty.

[Anthony Caruso]

You may also want to find a new place for the hard drive. They don't like magnets and speakers are magnetic. Don't know if it would be enough force to mess with it, but I'd be better safe than sorry, especially if it sat up there for long periods of time...

[@?,*???&?]

I just ordered a pair of these to see what they do. I've got a few pieces of gear that exhibit a fair amount of noise. My furman spring is susceptible.

http://www.powerwraps.com/

It looks like these are merely shields for power cables to keep RF out.

I'll let you know what they do, seem to do, if anything. The concept looks good for not alot of $$.

[jv]

You also say you have a big CRT - those can generate a lot of noise, depending on where they are placed, etc... Try turning the CRT off and see if the noise goes away. When I switched from a CRT to LCD display, it helped a lot.