This is a guide for dealing with these problems, both in your recording and also in editing if you're otherwise happy with the take and want to try to rescue it.
All of the examples are taken from the audio file illustrated above.
This is distortion caused by speaking or screaming too loudly for the poor, sensitive microphone. The wave form goes vertically right out of the box.
Even reducing the volume can't save this file: as you see, the quieter file is still cut off flat along the upper and lower edges, so it will still sound distorted.
The remedy? Re-record. If the lines need to sound loud, you can experiment with stepping back a little from the microphone, turning your input volume down, or attempting the opposite of a stage whisper- sounding as if you are loud, whilst actually not hitting the decibels. It's not easy and it can take quite a bit of experimentation, depending on your equipment, but it's essential.
Plosive sounds, particularly 'p's, can cause puffs. When listening, you can hear the air puff across the microphone, which can be distracting for the listener.
These are usually preventable in recording by using a pop screen, which is a must for any voice actor.
You don't need anything fancy and there are very straightforward instructions for making one from nylons and an embroidery hoop here.
You can also angle your microphone so that it is above, below, or slightly to one side of your mouth.
Sometimes the odd puff will breach the pop screen's defenses, but it may be possible to save the take. If you zoom in on the beginning of the syllable with the puff, you'll see something like the picture above: the puff is in that backwards 's' shape. You can zoom in very close and remove the highlighted part in the picture, leaving the very first dot of the sound and matching the end up after the puff where it crosses the middle horizontal line, to keep the sound smooth. It doesn't work every time with every puff, but many times it will. If you're removing your own puffs, you do need to listen carefully afterwards with headphones to make sure that it is unnoticable.
The above solution is time-consuming and fiddly, though, so if you're puffing with any kind of regularity, you should readjust your recording setup rather than give your post-producer or yourself such a lot of work.
Popping is made by saliva. It produces tiny, high pitched clicks in the words.
To avoid this problem, keep drinking water while recording - and eating a slice of green apple beforehand keeps pops at bay for quite some time.
Pops are sometimes very difficult to find in sound waves. If they're big enough, you'll notice them as a blot on the wave.
The rest of the sound wave tends to follow some smooth kind of pattern (here an 'm'-like shape). To remove the pop, make sure to cut out the entire sound wave shape to ensure a smooth cut. Here, the highlighted piece starts at the tail of the previous 'm' shape and so continues until the tail of the next 'm' shape with the pop in it. Remove that shaded grey area and the line flows seamlessly. You can use one of the horizontal lines to help you to cut in the right place.
Again, this is usually, but not always successful. Listen with headphones.
A final note
Most post-producers for audio drama may be happy to remove the odd puff or pop - as long as they are fairly rare. This, however, is aimed at auditions, professional projects or others where you are doing your own post-production.
It is, of course, sometimes quicker to do a retake, but hopefully this gives you the option of trying to save that one, perfect take!