So here are my takes on post processing. Probably not what you wanted, but you asked for it.
First point is, why post process? What especially do you want to achieve? Unless you have this in place it will mostly be a non-directed process. One of the really important things to consider is when to stop.
And this brings me to the first main point -- can you hear when to stop? You then need a decent playback equipment that you are fairly used to. My personal guess is that you should aim for a specialized sound card (not one of those game cards, Soundblasters or whatever) and a good set of speakers or headphones. Given that good speakers start well above headphones and also are influenced by the room, open back headphones should be your first stop. Open backed because, in general, these are more true to the sound than close backed ( and as always, there are exceptions ) . I like the higher number Sennheiser ones, HD600 is a good choice if you ask me and it will cost a bit of money. Budget is a limiting factor for us all, but do try to go a fair bit above the typical iPod earbuds.
Now, to why you want to post-process. I will not look into the very obvious things such as compressing to mp3 or FLAC or whater in order to save some bandwidth. I will also assume that you have an idea if you want to chop things up into songs, remove dead moments and so on. So why on earth then process. Only you can answer that, by I tend to do it because:
- to make it sound better
- to make it sound more even
- to make it sound louder
Each of these takes its own part of the process. Lets start from the end. And this is actually what i do last in the chain, making it louder.
First, donĀ“t try to make it sound like a commercial CD recording in loudness. This will most probably spoil the whole purpose of everything else. There is a volume control on all playback equipment, use that. But we could move things a little way up in volume.
The ideal is that the peaks goes almost all the way up to 0dB but never quite there. Reaching 0dB will sound bad on many types of equipment. So keep a good headroom left, somewhere around 1 to 3 dB is a good point to aim for unless you know your software really, really well. One tool you can use is normalizing. This will raise the level without otherwise changing the sound.
A small digression here. Doing all your processing of 32 bit float files in the computer is a good bet. This saves you from a lot of issues and keeps quality through the process. The very last step then is converting to 16 bit or whatever format you want to present the results.
Another tool you can use to raise levels is called a limiter. Limiters comes in many different flavors and are used in different ways, but they all have one thing in common : use them too heavily handed and all sounds like shit. Easy does it. You also need to know if the limiter actually limits to a max level (say -1dB) or if it lets some peaks pass through. They are all different. Limiters work by keeping the odd peaks of volume down, allowing you to raise everything else. You need to listen to the result carefully when using a limiter.
continued in next post ....
// Gunnar