Multitrack recording is widely used technique that has many great benefits over single track recording. Multitrack recording is the method that should be used when recording music performances, compositions, and even with filming. When it comes to recording music for the HSC, a multitrack recording has many benefits and it is not that difficult to do.
Audio Recording with the Zoom H5
Not every school is going to have access to the latest and greatest of gears, however, there are many cheap devices that can achieve great results. If a teacher is in a school with access to great digital mixers, then they can use that to record into a storage drive or directly into a DAW. A Zoom H5 (or other products in the audio recorder line such as a Tascam DR-44WL) is a relatively cheap stereo recorder with built-in condenser microphones in an X/Y arrangement. The Zoom H5 and H6 have changeable microphone capsules, expanding the possibilities. For a cheaper and older model, the Zoom H4n is also a viable option with the added possibility to change the stereo microphone positioning to as wide as 120º. In the multitrack recording mode, the Zooms can record using the built-in condenser microphones, as well as 2 additional microphones connected via XLR or TRS. Using good microphones in a stereo arrangement can create great recordings, and the audio can be combined with the built-in microphones. For example, a Zoom can be set up on a tripod back from a performance space in a hall, allowing the built-in microphones to capture a lot more of the ambience. Using 2 other microphones in an X/Y closer to the sound source will get a clearer sound, which can be mixed with the more ambient recording later on. With the H5 and H6, even additional extra microphones can be used due to the EXH-6 Dual XLR/TRS Combo capsule, or the extra slots built-in on the H6. An X/Y recording is good enough, however, for a much larger ensemble, a Decca Tree technique can be used. See below for a slideshow of useful layouts (sourced from http://lossenderosstudio.com/article.php?subject=11)
The great thing about using the Zooms or similar devices is that the multitrack recordings are synced. Phase cancellation won’t really be an issue in a hall or wet room, however, if it is, it can be corrected inside a DAW. If the Zooms or handy recorders are not available, there are cheap USB audio interfaces that accept XLR inputs. Using this method is still great and can record directly into a DAW on a computer.
Most recorders have options for the recording format and sample rate. I may be an audiophile when I say go for the highest quality possible, but please do it! The Zoom H5 can record in 24 Bit WAV at a 96.000 kHz sample rate (CD quality is 16 bit PCM at 44.100 kHz). Obviously higher quality audio requires more storage but high capacity SD cards are becoming somewhat cheap these days so space shouldn’t really be an issue. The Zoom can record in mp3, which is good if you want to quickly record and send the files. If you wish to edit the audio, it is best to work with an uncompressed audio file like WAV. After editing, exporting as an aac or mp3 is not an issue, however, please do not export to mp3 to burn to a CD! Burning to a CD will encode it as PCM, which is lossless audio, making it like a WAV again, only without the quality information you totally decimated when you converted to lossy audio… rant over.
Using multitrack recording is also great as a backup if something goes wrong in the main microphones. On a Zoom, if the plugged in microphones get knocked or the cable decides to crackle, the built-in microphone recording can be used as a backup. This is called redundancy recording, and it can be a good idea particular in live performance areas. The Zooms can also have a backup recording feature that records at a lower gain. This means that if the main recording clips, it can be salvaged from the backup file. This is good because sometimes unpredictable things can happen, although when sound testing it is a good idea to test the loudest section to get the input level correct. Too much gain can result in too much noise, and too little can result in a very quiet recording. -20dB to -12dB with no clipping peaks is a good range to have audio sitting at when recording.
Recording Audio for Video
If you wish to combine audio recording with video recording, it is actually quite simple. You do not need massive expensive broadcast cameras because you can easily use a DSLR camera to record good video at 1080p. You can actually mount a Zoom recorder on top of a DSLR camera and make use of just the one tripod as well. To make the audio and video easier to sync, you can use a 3.5mm audio cable from the Zoom’s line out to the DSLR’s line in to override the built-in microphones. Sometimes some cables have too much noise floor, luckily, there are cables designed specifically for this task and reduce the noise.
So, we can record audio with more than one microphone… what about recording video from more than one camera? Unless you have great gear, syncing video recordings require extra effort. Have you ever wondered why they have that board they clap when they say “action!” in movies? The board is called a clapper board and it is used to synchronise sound and picture. The boards are useful because they count the takes, letting them quickly find the corresponding audio files for the take. A clap is a very transient sound and anyone familiar with waveforms would recognise it.
Chances are, you do not have a clapper. Alternatively, you can just clap very hard or slap two books together to create the transient sound. So you know what the sound does, how does it align to video? Simply, you just find the frame in the video when the two objects meet (hands, books, clapper) and line it up with the start of the transient clap in the audio. In a non-linear video editor like iMovie, Final Cut Pro, Sony Vegas, or Adobe Premier, you will have to zoom in on the timeline to see individual frames. If you recorded video from more than one camera, you will have to sync each file. Once in sync, you can edit the video to your heart’s content, using linear video editing techniques to control which footage is being displayed.
Using multiple cameras is great, as one can be used as a static camera angle, and others can be more dynamic with zooming and panning. When recording music performances, camera shots on soloists is possible and swapping between the cameras makes it more steady. When one camera isn’t being used, it can be getting into position for when it is active.