Nasal issue

[abell1234]

If the singer doesn't song good going into certain ranges, you need to tell him to stay out of those ranges, or just leave it the way it is. I know that sounds stupid, but I don't think gear can help a bad singer. Good luck.

[Insomniaclown]

I will typically throw up a really accurate spectral analyzer such as RN digitals inspector plug. I will then take a really close look at which frequency range spikes. I know that sometimes my voice spikes quite badly in the 1.5 to 4k range on certain notes. Then you can do a lot to fix it. EQ it out, multi band compress it, use a saturator plug to sweeten it, or use a spectro scope with adjustable gain to lower the gain on that frequency range and only on those instances where the peaks are bad. If all else fails, getting the singer to back off the mic when they go for those notes can soften those frequencies as well.