I have written before about the benefits of recording direct to stereo and that post has proved popular so I wanted to go in to a bit more depth about how I decide if direct to stereo recording is suitable to use and what setup I might use in a couple of common situations. The main advantage of recording straight to a two-track setup is, as Joe Boyd points out in the comments to the previous post, that it tends to make the recording sound like events. It creates a feeling of integrity to the preserved moment.
Can the musicians perform the song together?
The crucial thing here is the moment to be preserved. With a direct to stereo recording you are capturing what is happening in the room, the live performance, so the quality of that is vital. There are some genres of music where this choice is easy, classical, jazz and folk all lend themselves to this approach as they are idioms based on performance. It can work well for rock/pop genres too. Indeed it can create a recording of great immediacy, but there is less scope for post-production. This is both the blessing and curse of direct to stereo recording.
Does the room sound OK?
This is the big decision for me. The musicians can all be monsters combining to make an amazing performance but if the room sounds horrible you’ll end up with an unpleasant recorded sound. If you have time to find the right room make the most of it. Try to get the musicians to come and play in a few rooms, use your ears and walk around the room listening for a sweet spot. It is worth bringing a step ladder along for this as the crucial point might be higher from the floor than your ears when you’re standing up.
The length and quality of the reverberation in the room are the prime consideration for me. The ideal varies depending on the type of music, a church with about two seconds of reverb time might work wonders for a choir but sound awful for that bebop quintet. You can get a pretty good impression of this by clapping your hands or shouting out short sounds and listening to the reverberations.
Do I have good mics for (at least) the stereo pair?
I like to use a stereo pair configuration as the primary recording source. It is always a good idea to use the best microphones you can and for this role quality makes a huge difference. Cost of the mics isn’t the ultimate judge of quality but you’re going to need more than a couple of SM57s for this kind of recording. I often use a M&S configuration with a cardioid and figure of eight but spaced omnis, A/B or X/Y can work just as well or better in different rooms. In general the A/B and X/Y configurations will focus on the sound in front of them more than M&S or spaced omnis. The choice depends on how the room sounds to you.
Do you need a bit more than the stereo pair?
Depending on the room and the musicians sometimes all you need is the stereo pair but in many situations you need a bit more control over the sound. This is usually best addressed with a few spot mics to allow you to balance the overall sound. The key to good results is almost always to keep your setup as simple as possible. Not every musician needs a spot mic and the fewer you can get away with the better.
This is very a very different kind of approach to the isolated source techniques that might be used in a typical rock band recording so the spot mics tend to be a moderate distance away from the player, perhaps even as much as three meters depending on the distance between the musicians. You are looking for a position that emphasises the source that needs a boost and perhaps most importantly you’re looking for a position that blends with the stereo pair. I would take a better blend with my main pair over better isolation in this situation every time.
Take the time to get a great sound from your mic setup
The quality of your recording is largely down to the mic setup in this situation. Take the time to get it right. Use your ears to find that sweet spot for the main stereo pair and check for any nasty anomalies the room might throw at you. The big baddie is phase and this is why a simple setup with fewer mics is much easier to wrangle.
One basic thing to look out for is make sure that your main mics are not equidistant from any walls and not in whole number proportions either (e.g. the distance from the front wall is two times the distance to the back wall). The variation in length of sound waves is massive from 1.7cm at 20kHz to 17m at 20Hz so beware of potential resonances. Your ears are the most important tool here. Listen carefully to what your mics are picking up and if you’re using spot mics use the phase shift button on your desk or preamp to see if it makes a difference. If it does you should try another position. If the problem is at high frequencies moving the mic less than a centimetre can have a big effect.
Set up your mix
The aim is that this isn’t just a monitor mix. This is the real thing. You’re asking the performers to nail it so why shouldn’t you have to get it right live too. Of course if you can recording the discrete channels is always a good idea too. Adding a touch of a spot mic into your stereo mix can be all that’s needed to save a great take.
Be gentle with spot mics. The stereo pair is the sound. The spot mics are there to augment that not to become apparent separate sources. You are capturing not creating the moment.
For a large choir in a good sounding church singing renaissance music I might use a pair of omnis somewhere between 30cm and 60cm apart at least 2 meters off the ground and about 8 meters from the choir. If the room sound is not so great I might try an X/Y configuration with two coincident cardioids at an angle of 120º. This will give you a bit less of the back wall reflection and emphasise the direct sound more.
For a jazz quintet of sax, trumpet, piano, bass and drums I would start with my M&S pair and consider a spot mic for the drums particularly if the drummer is a subtle player (they do exist). To deal with any other balance issues I would try physically moving the players first and only then introduce spot mics. I wouldn’t do this for the horns and for solos they can step closer to the main mic pair. Most jazz quintets are pretty good at balancing their own sound for rhythm section solos.
Have a go
As with most things there is no substitute for experience. If you’re interested in this kind of thing see if there is anyone you could record. School bands, choirs and even local jazz ensembles are often willing to give something a go for a free recording. Perhaps you can get them to cover the cost of renting some mics or see what you can borrow. If you’re giving your time to a community group people will sometimes chip in with help.
If at all possible try a few different mic setups at the session to see what you like best. If the first thing you try sounds good still go on to try some other setups. Perhaps they will be even better and having those recording to compare will stand you in great stead as you move forward.