constant noise in speakers

theAdrian · 5th November 2009, 6:12 AM

I have a constant low level noise hum coming through my speakers on my computer. i can change the way the hum sounds by the activity on my screen - an example is if i scroll through web pages, the noise sound alters.

i know its NOT a line in/line out issue with my sound card (M-Audio) OR my monitor. I have done a large amount of troubleshooting and i highly suspect it has something to do with the power supply and/or bad grounding.

what are some recommendations for very high quality, very low noise and very well grounded (lol) power supplies? (between 550w and 750w approx)

any other tips tricks and advice most welcome!

Edstructicon · 5th November 2009, 6:13 AM

try earthing your case or amp if you're running one, just grab some wire and attach it to something well earthed.

LostBenji · 5th November 2009, 6:58 AM

Induced noise and it's actually coming from the MB instead of the PSU. Clamping ferrite beads around the power leads to the mainboard may help reduce a little but you won't get rid of the rest so easilly. You may also have a ground loop between your PC and the devices (Amps or powered speakers) as Ed has mentioned above but the varying sound with system load is more indicitive of mainboard noise.

A hardware sound card will help alot but not as much as using a digital stream (SPDIF) to and external decoder (most AV receiver amps do this) will solve the issue totally.

theAdrian · 5th November 2009, 4:54 PM

thanks for the the replies guys.

I have a pair or powered monitor speakers (Behringer Truth B3031A) hooked up to my M-Audio audiophile 192 sound card. Can i have some details as to how i can earth the speakers? specifically, where do i put the earth wire? etc..

Edstructicon · 5th November 2009, 5:00 PM

Quote:

Originally Posted by theAdrian

thanks for the the replies guys.

I have a pair or powered monitor speakers (Behringer Truth B3031A) hooked up to my M-Audio audiophile 192 sound card. Can i have some details as to how i can earth the speakers? specifically, where do i put the wire? etc..

Ah well if they're monitors you'll have to hope they are earthing well enough through the 240v ground. You can always unplug them from your PC and see where the noise is coming from.

It may be noise from your PC, but if you've got something with a break-out box I don't think that would be the problem, but if its an internal card it may not be sheilded properly or something.

chrispychipS · 5th November 2009, 5:36 PM

how is your sound card connected to the comp.

it sounds like an external sound card.
if you connected thru the front try the back, the interference
is probably picked up on the length of cable routing from the
board to the front.

if it isnt an external soundcard, then youll need to come up
with a way to shield the card, or get one that has shield already.

theAdrian · 5th November 2009, 6:27 PM

heres is an idea of my setup.

btw, I tried putting some sheilding rings around the power chord on the speakers but no change. The shielding rings were a bit big though and i had to hold them in place with blutack otherwise they will slip about.

LostBenji · 5th November 2009, 6:55 PM

http://www.behringer.de/EN/Products/B3031A.aspx
http://www.m-audio.com/products/en_u...ophile192.html
http://www.m-audio.com/images/global...&cable_RGB.jpg

OK, so you have active speakers and your only connecting with un-balanced RAC leads or are you forgetting to mention that you are on the ballanced outputs ?
Ground loop is the good of being an issue there. You will have current flowing between devices via the sheild which then induces hum. You need to decouple the card from the speakers and if possible, used balanced line. Going by the website for your card, it supports balanced outputs, if this is the case then definately use them.

Example: http://www.bcae1.com/ballndrv.htm

However, you said the noise was dependant on what you are doing on the PC which comes back to noise in the system.

theAdrian · 5th November 2009, 7:08 PM

Quote:

Originally Posted by LostBenji

http://www.behringer.de/EN/Products/B3031A.aspx

However, you said the noise was dependant on what you are doing on the PC which comes back to noise in the system.

any ideas how i can help remove bad grounding to the motherboard? so do you mean placing ferrite beads around the power supply lead to the motherboard? - http://www.techfuels.com/attachments...-connector.jpg

LostBenji · 5th November 2009, 7:18 PM

How are you connecting to the speakers first please ?

Quote:

Originally Posted by theAdrian

any ideas how i can help remove bad grounding to the motherboard? so do you mean placing ferrite beads around the power supply lead to the motherboard? - http://www.techfuels.com/attachments...-connector.jpg

You don't. If the noise is induced internally then you no option other than to use a external soundcard or better still, use the digital outputs to an external decoder. Keeping the audio in the didgital domain keeps it free of noise. The moment it is converted to analog is where the noise can start getting in. Sheilding the card is one trick but if the noise is riding into the card via the power feed to the card then your knackered.

theAdrian · 5th November 2009, 7:28 PM

Quote:

Originally Posted by LostBenji

How are you connecting to the speakers first please ?

You don't. If the noise is induced internally then you no option other than to use a external soundcard or better still, use the digital outputs to an external decoder. Keeping the audio in the didgital domain keeps it free of noise. The moment it is converted to analog is where the noise can start getting in. Sheilding the card is one trick but if the noise is riding into the card via the power feed to the card then your knackered.

thanks for the info, much appreciated!

LostBenji · 5th November 2009, 7:31 PM

Your still not answering the questions.

theAdrian · 5th November 2009, 7:38 PM

Quote:

Originally Posted by LostBenji

Your still not answering the questions.

at the moment i am using a high quality Guitar style jack lead from the monitors to the sound card. there is a XLR option i can use on the speakers also but i'm not sure how i would utilise them properly with my sound card.

http://i33.tinypic.com/30rnu52.jpg

LostBenji · 5th November 2009, 7:52 PM

The outputs of your soundcard are 1/4" (6.5mm) and are balanced. You simply goto any music shop and ask for balanced 6.5mm to XLR leads. Simple as that. This will ensure you have no induced noise on the leads and cuts down on the ground looping.

theAdrian · 5th November 2009, 7:57 PM

Quote:

Originally Posted by LostBenji

The outputs of your soundcard are 1/4" (6.5mm) and are balanced. You simply goto any music shop and ask for balanced 6.5mm to XLR leads. Simple as that. This will ensure you have no induced noise on the leads and cuts down on the ground looping.

okie dokie, ill buy the cables and see how i go! thanks

5th November 2009, 6:12 AM	#1
theAdrian Member Join Date: Feb 2005 Location: Albury Posts: 161	constant noise in speakers I have a constant low level noise hum coming through my speakers on my computer. i can change the way the hum sounds by the activity on my screen - an example is if i scroll through web pages, the noise sound alters. i know its NOT a line in/line out issue with my sound card (M-Audio) OR my monitor. I have done a large amount of troubleshooting and i highly suspect it has something to do with the power supply and/or bad grounding. what are some recommendations for very high quality, very low noise and very well grounded (lol) power supplies? (between 550w and 750w approx) any other tips tricks and advice most welcome!

5th November 2009, 6:13 AM	#2
Edstructicon Member Join Date: Dec 2003 Location: Newcastle Posts: 1,051	try earthing your case or amp if you're running one, just grab some wire and attach it to something well earthed. __________________ Furano 2010 Bingis

5th November 2009, 4:54 PM	#4
theAdrian Member Join Date: Feb 2005 Location: Albury Posts: 161	thanks for the the replies guys. I have a pair or powered monitor speakers (Behringer Truth B3031A) hooked up to my M-Audio audiophile 192 sound card. Can i have some details as to how i can earth the speakers? specifically, where do i put the earth wire? etc.. Last edited by theAdrian; 5th November 2009 at 4:57 PM.

5th November 2009, 5:36 PM	#6
chrispychipS Member Join Date: Oct 2008 Location: 2165 Posts: 77	how is your sound card connected to the comp. it sounds like an external sound card. if you connected thru the front try the back, the interference is probably picked up on the length of cable routing from the board to the front. if it isnt an external soundcard, then youll need to come up with a way to shield the card, or get one that has shield already.

5th November 2009, 6:27 PM	#7
theAdrian Member Join Date: Feb 2005 Location: Albury Posts: 161	heres is an idea of my setup. btw, I tried putting some sheilding rings around the power chord on the speakers but no change. The shielding rings were a bit big though and i had to hold them in place with blutack otherwise they will slip about.