First off, are you washing your box out when you change it? DON'T USE LYSOL, it's toxic to cats! Just plain soap and hot water can make a big difference in how the litter pan smells.
What type of litter are you using? I've found the scoopable varieties MUCH better in controlling odor. I was out of my regular brand the other day so I used some "Feline Pine" I'd bought some time ago. Phew! I didn't realize just how much difference scoopable littler makes! I was back to my regular litter in two days!
While several people have commented about Arm & Hammer litterbox products, I find them just too flowery and too expensive. What I started using several years ago and have been thrilled with is adding about a cup of plain baking soda to the litter pan and mixing it with Tidy Cat Scoopable. It's MUCH cheaper (Sam's Club sells 14 pound bags of Arm & Hammer Baking Soda that are much cheaper than the small boxes) and now I have virtually no urine smell.
One other thought though... I've had a problem with my cats peeing over the edge of the box. It caused a very smelly situation until I realized what was happening. A second littlebox, preferably one that's deeper, underneath the one containing the litter will help, especially if you line it with newspaper and sprinkle some baking soda on top before placing the filled litterbox inside it.
Now if someone would please tell me how to keep my cats from kicking litter EVERYWHERE? I tried a hooded box but cats lower on the pecking order kept getting trapped in the box by their more aggressive brothers and sisters; then they wouldn't go into it at all. I've also tried the litter collection mats (at over $25 each!) but they didn't work all that well and several cats thought they made great scratching surfaces, destroying the mats in no time.