5.7.3 Selection of Recording Equipment  The decision about the use of a particular piece of recording equipment depends on many matters. There are, however, a number of technical issues common to all field recording situations and these can be grouped under three headings: archival compatibility, audio quality, and reliability.  Archival compatibility The choice of the recording format in the digital domain has a long, and irreversible, impact on archival life: e.g. lossy compression formats may reduce particular usages. For this reason the recording device should be chosen according to the archival compatibility of its recording format. Current technology offers the possibility of recording directly to a file based format using hard disk and solid state recorders. Such devices usually provide a choice of several linear and data reduced recording formats. The selection of .wav or BWF .wav is recommended. Raw or proprietary formats should be avoided as these often have to be transferred to .wav or BWF .wav via proprietary software for future long term archiving. In keeping with archival recommendations, data reduced recording formats should not be used. An alternative to dedicated portable recorders is a suitably equipped laptop computer. With the addition of a high quality microphone pre amp and analogue to digital convertor (see Section 2.4 Analogue to Digital Converters (A/D)) sound can be directly recorded to a laptop using widely available recording software. The same recommendations regarding file format applies to laptops as well, i.e. it is generally best to record directly in the storage format. This solution is practical, but high power consumption, as well as the acoustic noise which may be generated by the laptop itself, and the conspicuousness of the computer make this suitable for only some situations. The laptop, and many of the portable recording devices, can be configured to record simultaneously to an external hard disk. This additional safety strategy is outlined in (Transfer and Backup of content in the Field). Audio quality The audio quality should be chosen according to archival recommendations in Chapter 2, Key Digital Principles. The requirement for good quality recording applies to all types of content. Contrary to widespread opinion, spoken word recordings benefit from the same high resolution as music recordings, in fact it may be argued that the dynamics of speech places more demands on recording technology than many forms of music. In addition, if detailed signal analysis (e.g. formant / transient consonant analysis etc.) is required, the higher quality is a necessity. Microphones The discussion below regarding microphones is limited to issues related to the creation of archival recordings. Much more can be said about microphones as these are, in essence, the tools used in the most creative and manipulable part of the process and it is recommended that any field recordist be familiar with the use of microphones. The use of external microphones, separate from the recorder, is recommended in the majority of recording situations. This minimises the inherent system noise captured by inbuilt microphones, and avoids handling noise when operating the recorder. The quality of the microphones should be sufficient to match the needs of the recording task as well as the specifications of the recording device, noting especially the signal to noise ratio (SNR). In order to capture the full dynamic range possible, and hence record 24 bit recordings, the use of good quality external microphones with a suitable preamplifier are necessary as most of the lower quality recording devices and microphones compromise at this crucial point. In some recording situations the positional characteristics associated with the event are important. To capture such information a pair of external microphones deployed in a standard array is required (see Section below). A standardised microphone array will provide comprehensible stereo sound characteristics whereas fixed internal microphones, as provided by many devices, usually do not match any standardised microphone array and are not manipulable. Condenser microphones are the most sensitive, and generally preferred for best recording results. Condenser microphones need phantom power which is normally provided by a professional recording device, (ideally switchable) but can also be provided by an external battery or mains powered supply. Condenser microphones tend to be more likely to be damaged in poor conditions and it may be preferable to trade off sensitivity and use more robust microphones such as dynamic microphones in some situations. Condensor microphones are also quite expensive, and very good results can be achieved with some of the higher quality electret-condenser microphones which, having a permanently charged capsule, can operate for extended periods of time on a small battery. Outdoor recording, especially with condenser or electret-condenser microphones, requires adequate high quality wind shields. Incorrect and ad hoc wind shields can be detrimental to the recording characteristics and alter the polar patterns of the microphones making the recording less predictable. Users should be aware of this effect when selecting and using windshields. Reliability Unreliable equipment has the potential to lose already recorded material or fail just when it is required for a recording. To minimise the risk of failure, recording equipment should be chosen to give the best possible reliability. Low cost consumer-grade devices are in many cases, flimsy and insubstantial, and easily subject to damage, and should not be used in the field before being extensively tested. In addition to more robust construction professional devices offer more reliable circuitry and interfaces, such as balanced microphone inputs, and so allow long cable runs and more reliable professional connectors. Even though low cost equipment is more likely to be susceptible to damage and failure, cost should only be an indicator of reliability and all field equipment should be tested extensively before being used in the field. Testing and maintenance Regardless of cost or quality, all recording equipment should be regularly tested and maintained to ensure accurate and reliable functionality especially under field conditions. The integrity of the recording system should be tested, especially after equipment has been dropped or transported under irregular conditions. The frequency response of microphones should be regularly measured to ensure they are functioning adequately. Dust and humidity protection is vital in keeping equipment in good working condition. Regular checking and cleaning of the devices, including connectors and other surfaces is vital to maintaining a reliable recording device. Equipment should be allowed to acclimatise to changing environmental conditions, especially when moved from a cool dry environment, such as a plane’s cargo hold, to a hot humid environment. All test results should be kept to allow the production of a continuous report of the maintenance condition of field equipment and to foresee necessary exchange of components. Other considerations for field recording equipment Though the technical specifications and characteristics help determine the quality and reliability of a recording device, other practical issues can impact on the choice of equipment according to the envisaged recording situation.Important features include;adequate recording time when battery-supplied; a rugged and clear design; easy handling; and a small and light-weighted but robust construction. Illuminated controls are essential for recording in the dark but result in higher battery consumption. A decision should be made as to whether the recording situation makes devices with changeable media (such as Flash or SD cards) or a back up hard disk preferable to enable a suitable safety strategy (see Section 5.7.5 Transfer and Backup of content in the Field). Ideally the device should allow fast and simple data transfer and duplication, and have an inconspicuous design (the latter of which reduces the visual impact on a documentary recording, and may also minimise the risk of theft).