Eliminating noise / hiss

[manonthemoon]

I've read many posts about hiss, and people suggesting a noise gate or compressor, but I don't get it. When the device is playing, the hiss is just mixed into the background and it seems these devices only help when the instrument is not playing, and noise gates have attack/decay issues anyway. Why is it so hard to get rid of hiss? I have an electronic drum set, keyboard, and guitar, in a home studio. Even the two purely electronic instruments have hiss, but why? I'm playing through a Korg digital mixer, and then outputting via 1/4" to a P.A. system. That output signal, even if on headphones, has noise. I've gotten rid of buzz associated with grounding but the hiss remains. If I were recording something professionally, surely I would need to get rid of that noise and not just cover it up with instrument noise, right? So how do professionals do that? What piece of gear do people buy and put in a rack to eliminate all junk noise when doing a professional recording, or just wanting to play with "nothing but instrument" sound coming through speakers?

 

[mshilarious]

All electronics have noise as a basic principle of physics, the issue is how high is the noise level? In a properly designed modern signal chain the noise level should be subaudible. There isn't a magic piece of gear to "remove" noise, instead you need to go through your chain and make sure you have proper gain staging throughout. If a piece of gear proves to be excessively noisy, you would want to consider replacing that with quieter gear.

Generally, you should strive to get the signal level up to line level as early as possible in the signal chain, and keep it there (avoid interim attenuation followed by additional gain stages). The first gain stage needs to have an adequately low noise specification, after that it shouldn't be that important.

Once excess noise gets added into the signal, it's very difficult to completely remove. Compressors (set for compression) will raise the noise level, that's the opposite of what you want. Noise gates can help but of course have their limits. Automate all tracks so their noise isn't in the mix when the tracks have no program material.

Finally, there are digital noise reduction plugs that can do a reasonable job at a few dB of reduction, more than that and the artifacts of the algorithm because more objectionable than the noise.

 

[johnsuitcase]

Yep, gain staging is probably your issue.

Other possibilities include poor connections/bad cables, using the wrong cable (an unshielded speaker cable as an instrument cable is a common mistake) impedance mismatches (using a high impedance source like a guitar into a low impedance input, like a line input.) Long low-level unbalanced cables will pickup some noise, a bad transistor in an amp will cause noise, an underpowered power supply can cause some noise issues.

I could go on, but you get the idea...

 

[tjsmithmusic]

hiss problems

One issue to also check out is the power amp for your monitors. Most high end systems use high end power amps. Cheap power amps hiss no matter what you do. So maybe replace with a nice power amp designed for quiet appications. One example is Churches. they require very quiet power amps because of all the speaking that occurs.