That's a funny question.
First of all your workin with fruity loops. Meanin your usin cheap sounds of fruity loops or u use your own samples.
In both case, you needa make sure sound your using are good quality and THEY GOT NO NOISE.
Second, you work on a pc with probably a low value sound card.
Third, you're workin with effects that generate noise!! Yes it's true, low noise effect cost the price. Waves, Timeworks, Steinberg, any pc effect WILL DO NOISE. Ask any professionnal. you need to invest in hi-quality hardware effects, AND hi quality wires, or buy dedicated processors like Mackie UAD1/TC Powecore Firewire.
Fourth, after the beatmaker took care to build a song with the most clean possible sounds and samples, he gives the multitrack to a mix engineer, who will process each track separately. Then the mix engineer will give the mixdown to a mastering engineer, who will re-process the whole song.
And all of that with top notch equipment, and years of experience!!!
You can achieve nowadays mix at home that will challenge with the most equipped studios,
but you need a few years experience, and a minimum of stuff. Good monitors, good effects, a good interface/card, AND THE MOST IMPORTANT : good material to work with AND good ears.
Like honesty said, it's the GIGO rule : Garbage In, Garbage Out. (You'll hear that used by pro engineers)
If you want good sound to work with, try cubase or any VST host DAW, and some VST instruments. And if you got the budget, buy some synths or modules, like motif, triton, fantom or JV/XV from Roland. As well as many others like E-Mu's, there's a lot on the market used for not so expensive.