There was a time when all recorded music was made by putting the musicians together in one room and having them play together while the engineers captured their performance. As time passed and technology improved, this type of recording became less common and the musicians began to be separated – first by microphones on each instrument, then by gobos (essentially movable acoustic walls) placed around each instrument, then by placing them in isolation booths, and these days, often by recording one instrument at a time.
But there’s no reason why you can’t record the whole band in one room – while you’ll lose the total isolation between tracks that’s become a standard for contemporary recording, you may gain much more than you lose. When you have all of the musicians playing at the same time, the opportunity for interaction between them is much better than if you physically isolate each instrument, or record musician separately. If you subscribe to the philosophy that music is ultimately a conversation between musicians, playing in a room together is more like sitting around a table chatting rather than standing alone, talking on a cell phone. Let’s continue the conversation paradigm for a moment; if there are three or four people talking in a normal tone of voice but one guy is yelling, the conversation comes to a stop. Even if the musicians are wearing headphones, everyone has to be aware of their relative volume in the room so that the bleed from a single instrument (like drums or a guitar amp) doesn’t overpower the rest of the group.
With judicious microphone placement and the use of gobos to block direct sound, a great deal of the bleed will be eliminated – not all of it, of course; . These days, the standard procedure when recording is to close mike each instrument (or amp); when all of the musicians play together, each track will have a primary instrument, with some amount of bleed from the other instruments being played. There’ll be some ambience from the room (essentially, early reflections from the floors, walls and ceilings) as well as off-axis direct sound being picked up by each primary instrument mic. The idea behind embracing microphone bleed is to accept those early reflections as an integral part of the recording’s sound – after all, mic bleed isn’t a problem as long as you don’t think of it as a problem.
While there are real advantages to recording the whole band playing together in the room (communication between musicians, the interaction of the group playing together and the ambience of the room sound), there are times where it may be better for one (or more) instruments to be isolated from each other when recording. One of these may appear if you have to punch in to repair one instrument’s tracks. Why? Because bleed from other instruments can make the task of punching in to fix mistakes difficult to achieve without being noticed. For example, if you have a whole band recording live in one room and you have to fix a mistake in the acoustic guitar part, there are two options; the first is that you simply fix the guitar part – but you should be aware that when you have the guitarist fix his part, those measures where you punched in won’t have drums (or any other instruments) bleeding into the guitar mic. This lack of bleed will most likely change the drum sound in the final mix at the point where the punch was done. You can, of course, have the whole band play when the punch-in takes place (even with only the guitar track being recorded); this usually works well at maintaining the room’s ambience.
Remember that when EQ is added to a track that has other instruments bleeding into the mic, that EQ will affect the bleed into the mic as well as the primary instrument. For example, boosting the low frequencies on the bass track can change the sound of a snare drum that’s bleeding into the bass mic. This doesn’t mean that you can’t EQ tracks that have other instruments bleeding onto them; it simply means that you have to find the balance that works best.
A great mix is all about balance. Each instrument has its own place in relation to the other instruments in the track, a place that’s determined by by volume, by tone and by the sense of space that surrounds the instruments. The ambience added by microphone bleed can help define that space. Given the sheer musicality that can come from a group playing live in the room together, the relativelyt few disadvantages that can come from mic bleed are outweighed by the advantages. So embrace the bleed – it’s the right thing to do.