Recording - January 2011 - 17

through adapter cables for the typical mini-stereo line inputs. You can also use a standalone CD-R or hard disk recorder, but beware of any recorder that does not offer a running time long enough to capture a full-length concert. Of course, using a laptop is also possible, but be sure that the luminescent screen is not distracting to concert-goers, and that power saving features such as a screen saver and sleep mode are disabled before hitting record. You don’t want your computer to go to sleep in the middle of the second song! Lastly, a quality pair of headphones is essential when live recording, as your rig will rarely be isolated from the concert space. Don’t skimp on these headphones, as their sound will dictate your mic placement decisions. I love my Bose noise-canceling phones. They are expensive, but they have been worth every penny. I can sit in a venue, midconcert, and hear my recording over the ambient sound of a PA system. Before I got these noise-canceling phones, I had to monitor at painful, counterproductive headphone volumes. Stereo mics—keep ’em close Much has been said in this magazine and elsewhere about stereo miking approaches such as XY, Blumlein, Mid-Side, ORTF, and Decca Tree. While I won’t discuss these methods here, I will say that all work well when recording acoustic performances—again, Michael Schulze will tell you more about some of them on page 48. The fundamental premise behind these techniques is that it is important to keep the left and right mics close to each other. When microphones are spaced apart, they capture a sound source at different times, and when summed to mono this can result in nasty sounding phase cancellation. Another problem: When a mic pair is too widely spaced, the center of the stereo image can lose its clarity. The bottom line is to use your ears, but consider the destination of your recording. If your work will be broadcast on radio or TV, you will certainly want to employ a phase-coherent approach such as XY, MS or others. If the plan is use the material on a record, you might be able to get away with a spaced pair, separating the mics a few feet for a wider stereo effect. Move that mic! Although academic attention is usually focused on miking technique, the truth is that it is where you place the mics that makes the biggest difference. With acoustic music, such as an orchestra, a bluegrass combo, or choir, locating the mics at some distance from the ensemble is imperative for capturing a well-balanced mix of the instruments. Too close to the group and individual musical voices can stick out. The catch is that as you go farther from the ensemble, the stereo image will begin to collapse and the sound of the room will get progressively distracting. Our ears are amazing. We can experience live music in a reverberant room and easily focus on the direct stage sound without distraction from reflections bouncing off walls, the ceiling, and other hard surfaces. Microphones don’t have it so easy. Without the human brain to discern the direct and reflected sound, a microphone mushes all incoming sound together into a less-than-clear audio signal. To make matters worse, when recording indoors, we must battle the critical distance. In all rooms there is a measurable distance from the sound source in which the reverberant field becomes as loud as the source. The closer your mics are

to this critical distance, the more your recording will trade direct sound clarity for diffuse reverberation. With this in mind, it is imperative that we place the microphone pair close to an ensemble. Of course you must also avoid getting too close, as the collective balance of an ensemble will begin to break down at shorter distances. Finding the perfect balance between close and far mic positions is the real challenge and art in stereo recording. Unfortunately, with live performances, architectural limitations and/or sight lines usually limit mics from being placed in the ideal location. Most acoustic concerts are performed on a stage, and musical groups usually set up near the stage lip, allowing the audience to be as close as possible to the “action”. To the recordist’s dismay, this means that the best spot for microphones is often in the first or second row of the audience, ten or fifteen feet in the air. Nothing could be less desirable from the venue’s perspective. The front seats are usually the most expensive, and the lack of stage space and/or the presence of high ceilings means that putting a mic in this location would be visually distracting or technically unfeasible. The engineer must thus compromise, placing the stereo pair above the conductor’s head (too close to the group), in the air hanging from the ceiling, or in the back of the venue well beyond the critical distance. The board tape The real limitation with stereo miking is that it only works well with acoustic music. Once sound reinforcement is involved, placing a microphone pair close to a stage captures only those instruments that are inherently loud, such as drums and guitar amplifiers. Instruments that are predominantly reinforced, such as vocals and synthesizers, are not captured by the stereo mics. Sure, you can move the microphones further into the hall, such as next to the front-of-house (FOH) console, but sound quality will be reverberant, and dependent on the live-sound mix. The solution is often to make a board tape, that is, record the output of the FOH console. Unfortunately, board tapes are notoriously bad. As a front-of-house engineer I go to great lengths to avoid making them, as my live-sound board mixes will often omit musical elements that are already loud in the room. For outdoor venues this is not an issue, as I usually can employ all microphones on stage to create a well-balanced mix from the sound system speakers. In smaller indoor venues, however, drums and guitar amplifiers are loud on their own, and are therefore downplayed in my live mix. With this conflict in mind, I shun board recording, as it presents a live mix out of context, and can bring me grief when an artist listens to it later. This is one reason why sound engineers get grumpy when you ask for a board feed. They don’t want their best efforts to live in infamy! Solutions to the board tape conundrum vary. Sometimes a front-of-house engineer will make a special recording mix using spare aux sends on the console. If you are both the live sound and the recording engineer you might be able to pull this off, provided you spend enough time both mixing the live show through the speakers and checking the recording mix through headphones. If you are not the FOH engineer, then this might be logistically impossible. Asking a sound engineer to assist your recording by making you a mix, or letting you lean over his or her console to adjust aux sends in mid-show, might just strain the boundaries of the live vs. studio Great Wall.
RECORDING JANUARY 2011

Recording - January 2011

Table of Contents for the Digital Edition of Recording - January 2011