Elteto.net

Introduction

The inspiration for this article came from watching numerous DrupalCon and other Drupal-related videos that had a hand-held video camera recording the presenter's voice from a distance, rendering the audio unintelligible.

The video aspect of presentations will be addressed in a separate article.

Most consumer video cameras do not have high quality microphones, and in-camera microphones do a poor job at capturing speeches, especially from a distance. If the presenter's voice is amplified by a speaker system, the volume can overwhelm the in-camera microphone, causing distortion, in addition to excessive echoing and muddiness.

Adding to the problem are the room noises, which are normally filtered out by an on-site listener's brain, but are indiscriminately recorded by a microphone. These unwanted noise sources are closer to a camera in the back of the room than the presenter is. All noises are reproduced at the same level during playback as other sounds and voices are. The video viewer will hear mobile telephones beeping and ringing, people typing, whispering and talking.

Microphone Configurations

A higher quality technique is to use a shotgun microphone, a directional device designed to focus on the sound source it is pointed at. This can be a great piece of gear at smaller presentations if the presenter is not amplified, remains at the podium, and if the camera has an external microphone port (many cameras do). Keep in mind, a strong volume from an amplification system may still cause some interference. If using this type of microphone, mount it on a separate stand and point it at the presenter. This will ensure the presenter's voice is recorded at a consistent level, even if the camera itself points at something else. If the presenter tends to move, keep the shotgun microphone mounted on the camera so both audio and video follow him.

In my opinion, the best microphone for presentations is a lapel or lavalier microphone. It is widely used in broadcasting due to its small, inconspicuous size, and the ability to move around with it in a wireless configuration. This type of microphone is usually clipped on a presenter's collar (where he or she can easily forget about it and not be too conscious of its presence), and is connected to a wireless transmitter the size of a deck of cards. The wire can be hidden under clothing, and the transmitter easily slides into a pocket or clip on a belt. The receiver plugs into a microphone port or line/aux input of a recording device. Some video cameras do not have line-level inputs for real-time recording. On those models, use the microphone port.

Another advantage of a lapel microphone is that multiple presenters may use multiple microphones, and the outputs can be mixed together into a single audio track. Even if the presenter is already amplified by a sound system, the lapel microphone will be close enough to him or her that there will be minimal to no feedback. The presenter can move around effortlessly, without any consideration for microphone positions.

A similar solution to the lapel microphone is the headset microphone. This is connected and recorded the same way as a lapel microphone, but is worn over the presenter's ear, with a small boom extending towards the face. A great advantage of a headset microphone is its proximity to the mouth, providing even better noise isolation. However, some presenters may be too conscious of the small boom and may frequently attempt to touch and adjust it.

If all the presenters are sitting at a table, they can either be individually recorded with the previously mentioned solutions or with corded, unidirectional microphones, or with just a single omnidirectional microphone. Remember, omnidirectional microphones record all room noises within their reach.

Mixing

If only using one microphone, the easiest connection is directly plugging into the microphone port of the camera. While some cameras may have two microphone inputs, those models are rare, especially in consumer grade offerings. More than two ports are only offered in expensive equipment, sometimes in the form of a dedicated microphone mixer interface.

You can obtain such a mixer without having to upgrade to a pricey camera. Various mixer models offer additional features, but you only need multiple microphone inputs and one microphone-level output. Certain models do not even require power, while others add a line-level output.

If using a camera with a line-level input, you can use any mixer with a line-level output, and the microphone-level output requirement no longer applies. This increases the number of your choices, as most mixers have line-level outputs, but not always microphone-level outputs.

Having a mixer, even with only one microphone, gives you a lot of control. You can filter out unwanted frequencies, apply effects (if you feel they are necessary), route the sound to multiple destinations (i.e., laptop, sound system, portable recorder, video camera) and set an ideal recording level. When using multiple microphones, adjust individual channels to make sure all presenters are at the same volume.

Interface and Recording

Having effectively captured the presenter's voice and set the appropriate levels, it is time to record the show. You only get one shot at this, so make sure you plan and test everything in advance. Ask the presenter for a sound check a day or hours before going on stage. He or she will probably be happy to cooperate, since you are working hard to capture the show, helping him or her to shine.

An obvious choice may seem to be to record the sound on the camera along with the video. However, this creates some problems. If you move the camera, your range is limited by the length of the cable, unless there is a wireless connection between the microphone/mixer and the camera. This adds extra equipment, expense and a possible source of interference.

Every time you move with the camera, it will look like a scene from Blair Witch Project. To avoid such unprofessional footage, you may decide to pause the recording while you set up a different angle, but then the audio recording stops as well. I will discuss videography in a separate article, but a quick advice for now is to keep the tape rolling, you can always use insert footage later to mask your hand-held sections.

The best way to capture a presentation is to record audio on a separate device. While it will require you to later add the audio track to the footage, dedicated sound recording provides incredible flexibility in post-production. You can keep the sound going while alternating between footage of the presenter, the audience and screen captures form the original slide show.

You can record the audio to a laptop through any decent audio interface. Most laptops have USB ports, and many have FireWire ports.

There are also devices on the market that capture a microphone or line-level input to an iPod.

You can simply use a portable recorder, a dictaphone, or even a tape recorder with external inputs. Any device that captures sound in a digital format will give you an easy-to-copy sound file you can most of the time simply drop in the desktop video editor software. If your recording device is analog, you can simply capture it to a computer with one of the aforementioned audio interfaces.

For redundancy, use multiple recording devices with either a dedicated splitter or if your mixer has multiple outputs. This ensures that even if one device fails, the other still records the full presentation.

If on a tight budget, capture the presenter's voice on a portable recorder or dictaphone placed on the podium or in the presenter's shirt pocket. Increase the quality by attaching an external microphone to the recorder. Simply grab the sound file after the show and copy it to the video editor software.

Editing

Most video editor software titles have at least limited audio editing capabilities. More advanced (and therefore, more expensive) titles even offer equalizer and noise filter plugins. Find open source video editors here.

If you wish to edit the audio separately, two great programs are Audacity and Reaper. They both support plugins, and there is a nice selection of free plugins available on the Web. Reaper comes with a number of useful ones out of the “box”.

Conclusion

This is not meant to be a complete lecture on audio recording. My intent is simply to provide multiple recording solutions at various price levels for different presentation situations. A videographer wishing to enhance the quality of sound tracks in videos has many options. Do not be afraid to check out eBay for any of the products you see in the links up here. Always make sure there are close photos of the actual item on sale, not just a product promo shot. Do not order “as is” or “no returns” items. Be very careful with used microphones, their quality may be degraded with use.

Shop around, and happy recording!