I tend to add quite a lot of saturation to the drums in the mixing stage. Why is that? It's because the sound is usually not aggressive enough to start with. I'm not talking about inserting a Big Muff in the snare chain. I'm talking about light tube, solid-state or tape-like saturation.
Well, why don't I just make the drums sound aggressive in the first place? There is one big reason for it. It's not possible with cheap gear. The saturation on most cheap gear sounds bad. More like clipping. Many higher end preamps and compressors have great saturation characteristics when you drive them hard. The problem is that they are very expensive. Analog tape and recorders are also expensive and require a lot of knowledge. Luckily, there is one cheaper way to get good preamps. Some older mixing desks sound great and you can find them pretty cheap these days. They just take a lot of space.
So, what makes a preamp good? To me, it's not a neutral and transparent sound. To be honest, I hate that. The sound you want for metal is not transparent. Most of the time you are going to have to do some very radical post-processing to get the sounds you hear in your head. I love preamps that saturate nicely and have a full and colourful sound.
There are no rules as to what types of preamps you should use for each part of the kit. Just make sure you are using the best preamps for overheads, snare and kick. The safest way is to use the neutral ones for overheads and coloured ones for snare and kick. But experiment! Another approach would be to use the same preamps for all tracks. There's nothing wrong with that either, as long as the preamps are good.
The last device in the chain is the AD converter. You can quite easily tell the difference between a bad and a good AD converter. It gets harder when you need to choose between two good AD converters. Just buy the best ones you can afford. However, one thing to keep in mind is that many great sounding metal records were recorded to Alesis ADAT machines, which had poor AD converters compared to today's standards.
Processing On the Way In
If you are feeling brave and are absolutely sure what you are doing, you can equalize and compress the drums on their way in, but you need a separate control room to do this properly. The gear you are using would also have to be top quality to make it really worthwhile. If you have great AD converters with soft limiters, you can try to clip them. Just beware! This is a very risky thing to do!
