Cracks/hum/noise in monitors/headphones (SOLVED)

[dragonmoose]

Hello everyone!

I'm having a problem with cracks/hum/noise from my monitors/headphones. I got the problem today when replacing the computer. I've been using my mixer with my old Alesis M1 monitors for many years now with my old computer with no problems. A couple of weeks ago I bought a pair of Yamaha HS50M and with the old computer everything worked fine.

So, first, the setup:

Speakers: Yahama HS50M
Sound-card: Delta Audiophile 24/96
Mixer: Behringer MX1604A
Computer: http://www.inet.se/artikel/1517081/inet-vox-i7

The problem seems to have to do with the connection between the monitors and the mixer as well as the power supply to the monitors, since also the output from the headphones is affected when the cables between the monitors and mixer are connected.

Anyway, I'll list the states more clearly now:

* When the computer is turned off, there's no noise at all, only a very low hiss from the monitors (when the volume is turned up quite high)

* When the computer is turned on, the cracks/hums/noises are _very_ loud (in both monitors and headphones). When moving the mouse you can clearly hear this represented in the noise. However, when disconnecting the XLR cables from the mixer to the monitors, all noise disappears, also in the headphones. Also, if the connection remains but the power supply to the monitors are removed, the problem disappears.

* So, when listening in headphones, speakers turned off, and XLR cable connected the problem disappears if the power cable is unplugged from the monitor.

* When connecting my old Alesis M1 Active monitors, there is no noise at all (not in headphones either).

* The problem is the same when connecting the speakers with a tele-cable.

* It doesn't matter where I plug the cables from the speakers into the mixer. It is enough that a connection exists at all.

* I've removed the cables from the floor and made sure not to mix power/audio cables. This made no audible difference.

So, from this, it seems that somehow the combination of computer/speakers/mixer is a very unfortunate one. I bought a Yamaha-mixer a couple of days ago that I will try, I just don't have a power cable for it. It might work, but I doubt it...

So, any ideas? What would be your next thing to try out?

Best regards and thanks in advance!
/Elias

[stainless]

Welcome to HRS

monitor , mixer and cords are the same and the computer is the only change- then I would strongly suspect it's in the computer

 (same soundcard?)

Try pulling the sound card and cleaning the slot contacts (De-oxit... or at the very least a clean eraser) and then make certain it is completely seated-

If the soundcard is new (with the computer) it's possible you got a bad card

let us know how this 'plays' out

[dragonmoose]

Hello & thanks for the Quick reply/welcome

Yes, the computer seems to be the source of the problem.

Since my alesis monitors work though Im thinking that
the yamaha's are more sensitive to disturbing signals.

I will try to remove & clean the soundcard as you say. I will also
try another pci-port. The soundcard is the same that I had previously.

[dragonmoose]

Problem solved now. I've bought an external sound card (M-Audio Fast Track Pro). That got rid of a large portion of the noise, although not all of it. I got rid of it completely by plugging the monitors into a different power outlet.

I guess the root cause of the problem was that the power outlets are not grounded...

[stainless]

ungrounded outlets are not good as it's not uncommon for polarity to be switched which is potentially very dangerous- so I'd check all your outlets- and you should have a surge protector/power conditioner on your gear

having said that- glad you got is figured out!