Hey guys, I just got my Alesis 620 monitors yesterday. However I encountered a pretty strange noise problem. My setup is pretty simple: Computer > Edirol FA-66 interface > Alesis 620. When I have these connected I get a buzzing sound from the monitors, it's not 60Hz hum because the frequency is too high for that. Also it's not the monitors themselves because if I pull the TRS cables out, the noise is gone. Here is the weird part, I have a 2nd computer, a Sony laptop, if I run the setup through that instead of my desktop, there is no noise!!! I don't understand.

Here are some of the things I have already tried but to no avail:

Disable internal soundcard
Plug the monitors into their own wall jacks

This doesn't happen all the time either, sometimes happens and other times fine. But when it happens it is really annoying. I hope you guys can shine some light on this issue. Thanks!


EDIT: The headphone jack in the Edirol FA-66 is also inline with the monitor outputs, however I never detected this noise through my headphones.

60hz hum can have harmonics, and you may not necessarily be hearing the fundamental

sounds like a grounding thing to me, used to have a similar problem, laptop on battery worked perfectly fine, plug in the power supply and lots of hum.

the quickest way to check is plug in the laptop in the same place as the desktop

Hi LS,

I had a similar problem last weekend doing a live recording at a gig and have so far narrowed it down to the firewire port on my laptop picking up hard-drive noise. Try unplugging your firewire cable and see if the noise goes away. I'm not sure how i'm going to address my issue at this point but i'm doing some online research for people with similar issues which led me to your post.

On the firewire noise issue, SOMETIMES you can eliminate this kind of noise by running the wire around an inductor core, sometimes you see them on wires with the little boxes around them, you can jerry rig one using a big washer and wrapping the wire through it a couple times and see if that helps. Google "cable with ferrites" and choose image search and you'll see some good examples. The washer trick is not the best way to do it but can sometimes work in a pinch. This is usually to eliminate RF interference but can help with all kinds of noise sometimes.

Another thing I have had to do occasionally is run a ground jumper between two pieces of gear which make noise when connected together.

The computer with its 3 prong plug and the 2 speakers with their 3 prong plugs all plugged into the same power strip but there may be some deficiency in the ground to the sound card for some odd reason, you may have success by clipping an alligator clip right on to the metal back of the sound card and then on to one of the metal screws on the chassis of one or both of the speakers.

Another thing to try might be to try hooking just one of the speakers up and seeing if the noise is there, this may help reveal the source of the problem if there is no noise when one speaker is hooked up but there is noise in both speakers when both are hooked up.. Try one and then the other.

That being said, there may be a problem with the cable(s) you are using, try a different one(s) and see what happens. Sometimes a cable can work fine by adequately passing signal but will pick up all kinds of noise if it's not shielded enough or whatever...

Good luck
John

Thanks for the advise Poncival. I actually had a bunch of detachable ferrite coils laying around and tried putting them on the firewire cable already with no luck. I'll try a good ground next then maybe a different firewire cable. I have an HP DV6885SE and the firewire port is exactly where the hard-drive is so I think the noise is actually getting into the firewire circuitry before it ever gets to the cable. I might end up getting a separate firewire interface card as the expansion port is on the other side of the laptop, away from the hard-drive. The good news is that the noise did not affect my recording, however it did get into the return lines from my echo (AF12) and back into the PA.

Thanks for the reply guys. I went to Walmart yesterday and got 3-prong extension chord and plugged both monitors in it and plugged the extension cord in another walljack, and guess what, the noise is gone! Well at least a good 90% of it, there is still a slight buzz, but not nearly as bad as before. So I guess it was a grounding problem after all. I think I'll get a Furman power conditioner soon, and hopefully a new interface, because I think the residual noise is cuz by my interface.

EDIT: found a way to circumvent the residue noise, I turned down the gain on the monitors way down until I can't hear the noise anymore (about 25% gain), and just turn up the output volume on my interface. I'm still wondering what is the real culprit behind this though. The noise increases as I turn up the gain on the monitors, but this doesn't occur when the TRS cables are disconnected. Raising the output volume on the interface has no effect on the noise. Does this still sound like a grounding issue?

It's a gain staging issue. If you were to reverse the situation talking about a mic and pre, you'd pretty soon realise what the problem was.
Your monitors have self-noise remember.

Hi Liquid Shadow, just came across this thread and I've got exactly the same problem as you. Funnily enough I'm on a pretty similar set up: Computer > Edirol FA-66 > Fostex PM1's. The only solution I've found is also to drop the level of the monitors and boost the output on the soundcard. Sadly it doesn't completely remove the hum, just makes it a bit quieter. There's no noise when I disconnect the speakers from the FA-66 so I think the soundcards the problem. I've not really got a clue though as I know nothing about electrical wizardy! Would love to get it sorted properly, it's horrible working with a constant hum. Good luck with the Furman and new interface, let me know how it goes. Oh yeah... Think I'm gunna give one of these Hum Destroyers a go (especially as it's so cheap). Might be worth a look for you as well.

Behringer MICROHD HD400 Ultra-Compact 2-Channel Hum Destroyer | DV247

FeatheredSerpent:

I am aware that the monitors do have self-noise, however the kinda of buzzing sound I was experiencing is definitely not that, because it only happens when the monitors are plugged into the interface, so it must came from the interface or computer, the monitors just amplified it.


Ches:

I'm interested in the Hum Destroyer, report back to this thread after you get them! If it works for you I might get them too.

Hmm, are you guys bus-powering those units?

I see it's got a built-in analogue limiter too so that's potential for more noise, especially in such a little unit where al the components are crammed together.
I am just guessing here though, I'm not too sharp when it comes to electricity!

The first thing you need to do is get a pair of balanced cables for your monitors. I had the same problem and the balanced cables stopped the buzzing immediately. Never under-estimate quality cables.

FeatherSerpent:

I tried both bus-powering and power adapter, it doesn't have an effect on the noise.

You made a good point about the limited space in an interface. However I do not experience noise through my headphones connected to the interface, as well as my computer speakers connected to the interface. It only happens with my Alesis monitors.


Mike:

If you read the rest of the thread you'll see that I do have balanced TRS cables. It's not the cables that's causing the problem.

When you used the laptop and got no noise, was the power supply plugged in?

Are all the units in the system being fed from the same wall socket? (desktop, monitors, audio interface etc).
Have you tried using the ground lug on the back of the fa66 to earth it to your desktop pc chassis?
Which outputs did you have your computer speakers plugged into?

Yes when I'm using it with the laptop the power adapters are plugged in for both the laptop and the interface.

When I was testing it with my computer speakers I plugged them in the same output as with the monitors, with a splitter cable.

I haven't tried the ground terminal because I don't have any copper wire on hand.

You're still not plugging all the components into the same outlet though are you.. or are you?
Say you have 5 plugs - 2 for speakers, one for edirol, one for desktop and 1 (or more) for displays, they should all be running form the same outlet, either from a 6 point power strip or from a 4 point with 3 plugs inserted and then another 4 point (for example) inserted into the last sociket with the remaining plugs going into that one.

It has to be the desktop pc, or even a computer screen. Are you using a crt as a second monitor for the desktop maybe?

You've eliminated everything else seems to me.

Well everything is plugged into 2 wall jacks, the studio monitors + laptop + interface share one wall jack, the monitors are on their own extension cord. The desktop, 2 LCD screens (no CRT), computer speakers etc are plugged into a surge protector that uses the other wall jack.

Run everything from one wall outlet only (doesn't matter how many physical sockets that single outlet has), plugging your extensions into the other extensions so everything is running in a serial fashion.

See if that works. It should help.

And try that for both outlets, ie run everything off one, and then run everything off the other, have a look at your main circuit/fuse box and try and use an outlet that is running on its own circuit if possible.

Haha I don't think I made myself clear in my post, everything is plugged into one wall unit, which has 2 jacks.

I read over this whole thread, and I ALMOST have the exact same problem...

Differences: When I have my laptop plugged in, and monitors plugged into headphone jack in the front, I get quite an evil/loud buzz/hiss coming out of my monitors. It only takes a few clicks up on the gain (from -30dB) for me to hear it.
--When I unplug the monitors from the headphone jack while the laptop is plugged in there is no buzz. (no matter the lvl gain)
--When I unplug the laptop from its power supply with monitors plugged into the jack, there is no buzz (no matter the lvl gain).

They are KRK Rockit Powered 5's.
I do not have an interface. It is just straight Monitor to laptop connection

What I did to try and fix it:
--First, went and bought a regular Surge Prtector that was 20$ from Best Buy thinking it would fix it... Wrong-o.
--I was given unbalanced RCA cables when I bought the monitors. So I went back to Guitarcenter, got some Balanced TRS cables to see if they would do... Not so much.
--Thing about my TRS cables: They only have the tip and one blackish ring, I've seen some with two rings. Is two better than one for me in this situation? (Isn't the 2nd ring called a grounding ring or something?)
--I've tried every different powering combination. Had just monitors into wall, while surge/laptop power was plugged in another outlet. Had all power plugged into the surge, etc etc.

The guitar center guy said I had a grounding problem or something and he had something for 80$ to "possibly" fix it. I would rather try some 10-20$ cables.

My question: Would TRS cables with two rings probably fix it?
Or would a better Surge Protector with "grounding" capabilities fix it?

Hopefully this thread gets a kickin :D

Thank you for the replies. I try to be as detailed as possible, any questions, just holla.

Cheers

Try this:

Figure out what outlets are on the same circuit as your rig (some could be in other rooms) and unplug everything. If the noise has gone away, start plugging stuff back in until the nise comes back. A lot of cheap (and noncheap) electronics have power supplies and such that will induce hum like crazy. My Blackberry charger being one of them.

Yea I live in an apartment with two others, so unplugging everything isn't very viable. I'm pretty sure it's just my laptop causing the noise because it's the only thing that causes noise when plugged in. Hence what I described.

I was just hoping some cables with grounding rings would solve it. I am going to buy some this week to try it out.

Cheers

i seem to be having the same problem with my rookit 5's, it gives off this low hum , as if the volume is turned up to 110%
happens on my guitar amp too. the volume is at 0 and the speakers hum as if it's turned up to maximum volume.
the monitor speakers have caused serious damage to my ears in the past few months i've been to a few ENT's for my tinnitus, I bought a HUM-X and tried diff balanced cables. I still can't get rid of the hum...

Plug everything where you want but plug only your computer:

1) to another separate wall outlet (this outlet must be powered from the main electricity as a separate from previous already used outlet)
2) if likely noise persists then plug it to 2-prong outlet or through 2-prong adapter

Laptop could softly beat you with a low current. Use wireless keyboard.

I don't know maybe either 1 or 2 will work. But I tried only both at the same time.

The problem is interface USB and Firewire connections have ground to computer, computer has ground on the outlet. Monitors have ground on the outlets. And they also get the ground from the interface outs but it's computer ground from the same outlets grounded where monitors also plugged in. There's ground loop. You can't unplug your interface ground. So you can do something with computer or monitors and other stuff.