Noise

[typo]

i saw threndors post and thought a thread dedicated to "how do you find the source of noise and fix it" would be a good topic.

there's different types of noise: hiss, hum, clicks etc plus analog or digital distortion

the most common source of hum is your grid power supply and equipment ground loops. Check your grounding, and use a power supply cleaner/filter to clean up your system power

hiss, high frequency noise can come from lots of sources, including poor gain staging, environmental spill such as radio waves or computer fans

crosstalk is a common source of clicks. most common is caused by midi/control/power cables being routed too close to your audio. unfortunately some computers are very noisy and spill a lot of noise onto audio

[john]

Hey

Computers are notoriously noisey, particularly for crosstalk, and of course noise spill into your studio from case fans.

To eliminate noise, or at least to lcate the problem, try as simple a set up as possible. A pair of simple PC speakers (test using an mp3 player first), try them in your PC, no physical audio inputs, just output.

Unplug unnecessary external components. Unplug your midi leads.

Mute all sound sources. With all sources muted do you still hear the noise? If you don't hear it, try a process of elimination and enable only one at a time, play something from the source checking each time for the troublesome noise. If present on all sources (digital and analogue) you can elimate everything in the input signal chains up to the sound card pre-amps. If you did hear the noise with all muted, try using digital ouputs instead of analog (route to an external amp with digital in). Do you still hear the problem? If you do then it looks like a prob internal to your sound card, even if that is a problem shielding the audio circuits from spill from your pc motherboard.

Try the same process with your midi "in" plugged in, and run a midi stream into this port and try the same process of elimination. the same with only midi out, and then with both. Gradually re-introduce components until the noise appears.

To be sure, try your sound card in a different PC, try the same elimination process. Also if you can, try another sound card in your PC too, same process.

If you find the noise then you stand a chance of addressing it. If you find the noise never disappears it's likely to be your sound card, although it's possible that can be addressed if you can isolate where your sound card is still picking up noise from (like your central heating/air con, wireless stuff).

Cheers

John

[Nightwolf]

Include lights, fans, heater/cooler, and any transformers and power generators (big plugs from printers and the like) in your troubleshooting steps