Live Recording Tips Using the Alesis ProTrack
The ProTrack is the first handheld professional recorder for iPod. It’s like having a professional recording studio in the palm of your hand, and it records directly onto the most popular music device in the world. With no need for memory cards or sticks and professional connectivity options, the ProTrack is perfect for musicians, engineers, and other audio enthusiasts. In this article, you’ll learn some tips on making great recordings with the ProTrack.
Whether you are using the ProTrack for recording a show live at a concert venue, rehearsals and jams in a small practice room, or capturing the wide dynamic range of an orchestra, microphone technique can make a huge difference.
RECORDING LIVE EVENTS
The best place to hold or mount your ProTrack is in the center between the left and right sides of the stage. If you are in the audience, you’ll want to raise the ProTrack over the heads of the audience for clarity. You could hold the ProTrack up, mount it on a camera tripod, or, using the ProTrack Adapter, mount it on almost any mic stand.
Ideally, you should place the ProTrack at the point where an equilateral triangle (all sides are equal length) is formed with the left and right points of the sound source. The mathematical formula for this is half the width of the sound source times the square root of three. It’s helpful to have a calculator on hand to figure this one out!
That said, you might not always have a calculator on hand or you just might not be able to get to that exact spot, so experiment to make the best of your situation. The ProTrack’s headphone jack allows you to monitor the results of your placement and gain settings. You’ll want to make good use of this feature when you are scouting a place in the venue to set up your ProTrack.
The ProTrack’s built-in mics are great for quick, convenient recording since they are on board. The ProTrack also enables you to use external microphones to enhance your recordings, including:
- Specific microphones’ sonic signature
- Microphone placement and technique
- Safe installation of the ProTrack away from high-traffic areas or heights
- Long-distance installation of the ProTrack away from the sound source
One option in high-quality, low-cost microphones is the Alesis AM2 Stereo Microphone Set. It’s a complete stereo-miking kit with a pair of miniature cardioid condenser mics, clips, windscreens, a stereo mount, and a case.
The AM2 microphones have -10dB attenuation (pad) switches for use with high sound pressure levels and high pass filters that reject unwanted low frequencies such as rumble from handling, wind noise or overwhelming bass frequencies. These switches are recessed to avoid accidental alteration.
The AM2 microphones also come with a multi-purpose X-Y mount, which can also be carefully angled to perfect the pickup at various distances to the sound source. Using the AM2s directional microphones, you can employ miking techniques that enable you to record almost any situation in almost any environment.
The ProTrack also has a Phantom Power switch that provides +48V to power external condenser microphones. Refer to the ProTrack Quickstart Manual for more information regarding Phantom Power operation as well as your microphone documentation to learn whether or not it requires phantom power.
Let’s look at some of the most common stereo miking techniques.
X-Y position is the most common method for stereo miking in live applications. The advantages of X-Y are:
- Accurate, focused stereo image
- Convenient and compact configuration
- Zoom-like focus on sound-source area
- Prevents phase issues
- Rejects off-axis material (less ambient and background noise)
- Tight bass response
- Mono compatibility
How does it work? Start with two cardioid, supercardioid, or hypercardioid mics. These are directional characteristics that mean the microphones pick up sounds that originate in the front of the microphone, rejecting sounds coming from the sides and back to varying degrees depending on the pattern. Point the left mic toward the right side of the sound source and the right mic toward the left side of the sound source. Panning the left mic hard to the right and the right mic hard to the left creates the stereo image. The difference between the off-axis responses of each mic is what produces the stereo image. The close proximity of the two microphones allows for minimal differential between the response of the left and right mics, avoiding phase issues.
Experiment with the angle formed between the microphones. Setting a 90° angle is a reliable place to start. Moving the mics towards a narrower angle creates a wider image, while a wider angle between the mics tightens the image. If you are looking to capture more spatial dimension and room sound, here are some more techniques to experiment with.
This configuration captures excellent room nuance and stereo depth. It is a favorite of many concert “tapers” and is used by field-recording professionals. Start with two figure-eight (bidirectional) microphones. These are microphones that pick up strongly and evenly to the front and back, strongly rejecting sounds from the sides. Position the mics facing 90° to each other and each mic 45° to the sound source.
This technique also offers good mono compatibility.
In a great-sounding room, with two really high-quality microphones, nothing beats A-B technique for realism and detail. A-B technique uses two omnidirectional microphones, which pick up sounds from all directions evenly. Arrange the microphones parallel, spaced between 20 and 30 inches apart.
The delay between the time at which one mic hears the sound and the time at which the other mic hears it creates the stereo image. A good-sounding room is very important for getting good results with this technique.
Omnidirectional microphones do not exhibit proximity effect. When other microphones are moved closer to a sound source, they pick up more and more low frequencies. This is called proximity effect. It’s why broadcasters, announcers, and many rock vocalists address their mic very closely. Omnidirectional microphones do not have proximity effect, so they can be placed at a distance from the sound source without losing low-frequency content.
The A-B technique was designed specifically for stereo playback as phase issues can occur when it is summed to mono.
ORTF (Office de Radiodiffusion Télévision Française) technique rejects ambient sound well and has better spatial dimension than X-Y. You can use it for longer distances between the microphones and sound source to create a realistic or even a heightened stereo field.
ORTF technique combines components of X-Y and A-B techniques. The ORTF technique utilizes a pair of cardioid microphones placed 17 cm (7.7 inches) apart, at a 110° angle between the microphone capsules. This creates a pickup angle of 96°.
NOS (Netherlandse Omroep Stichting) technique is similar to ORTF but offers a wider pickup angle for a wider stereo image, thanks to a 30cm distance between the mic capsules. Angle the microphones 90° and space them 30cm (11.8 inches) apart. The differences between NOS and ORTF can be subtle but NOS has less off-axis coloration and truer spatial characteristics in exchange for slightly less focus and imaging.
Recording to the ProTrack using an iPhone or iPod touch
The iPhone and iPod Touch do not have the voice memo feature found in other iPods. This feature is what makes recording possible when connected to the ProTrack or other recording devices. To record with the iPhone or iPod Touch, you’ll need to install an app. We suggest BIAS iProRecorder, which is available from the Apple App Store.