Memory card type
— SD. One of the formats used in audio, video, computer technology, etc.; Almost every modern laptop has an SD card reader. However, the dimensions of such cards (32x24 mm) are relatively large for portable equipment, and therefore they are used relatively rarely in voice recorders. And they are often represented by more modern SDHC or SDXC cards with increased memory capacity and support for the high-speed UHS bus. Accordingly, SDXC support guarantees comfortable work with SDHC and SD, and SDHC support will not fail when connecting SD cards.
— miniSD. A slightly reduced (up to 22x20 mm) variation of the SD standard, otherwise completely identical to it (up to compatibility with SD-card readers when using simple adapters). It is rare due to the widespread use of even smaller microSDs.
— microSD. The most compact version of SD memory cards to date, have a size of 15x11 mm and a capacity of up to 4 GB. Due to their small size, they are widely used in portable electronics: in fact, they are the standard for mobile phones, and are also widely used in voice recorders. Like miniSD, they can be read by original SD card readers using an adapter.
— microSD HC. The second generation of the microSD standard; characterized by increased capacity, reaching 32 GB. In a voice recorder (and in general any card reader), ordinary microSD cards can also be used for microSD HC cards, but it is impossible to do the opposite — the card will not be read.
...— CompactFlash (hereinafter referred to as CF). One of the first memory card standards, it is still used due to its decent data transfer speed and impressive volumes (up to 128 GB). However, the dimensions of these cards are no less impressive — 42x36 mm. As a result, they are poorly suited for pocket format equipment and are rarely used in voice recorders — mainly in advanced models, where the priority is functionality and recording quality, rather than compactness. If the recorder is designed for CF Type II cards, it can work with all types of CF, and devices under Type I are only compatible with this type.
— memorystick. A proprietary standard developed by Sony and used primarily in its devices. It has a number of variations that differ in dimensions, volume and compatibility, and therefore, when buying a card for such a voice recorder, it is worth clarifying the specific MemoryStick specification used. The standard is rather poorly spread: firstly, because of its closeness (that's why, by the way, full compliance with it is guaranteed only in original Sony cards), and secondly, because of the high price of the cards themselves.
xD-Picture. Cards originally made by Olympus and Fujifilm for their digital cameras. The advantages of such cards are high reliability and compactness (20x25 mm), the disadvantages are high cost and relatively small volumes (up to 2 GB). As a result, dictaphones for xD-Picture are very rare.
Microphone type
The built-in microphone type determines the mode (number of channels) in which the voice recorder records sound.
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Mono. The simplest option: one microphone that records sound in mono format, i.e. without separation into left and right channels. It is impossible to provide a "surround" sound with such a recording, however, in the case of voice recorders, this is not decisive, because. usually in such a recording it is not the volume of the sound that is important, but the intelligibility of speech — and it is fully provided by a monophonic microphone.
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Stereo. In this case, a pair of microphones is usually used, spaced apart on the sides of the case; the sound is recorded in stereo, and the volume of the sound is achieved due to the difference in the sound reaching the left and right microphones. Considered somewhat more advanced than mono, although it does not provide better speech intelligibility by itself.
Power source
— Li-Ion
battery(lithium-ion). The most common type of battery for portable electronics today. Such batteries have good capacity, are not subject to the memory effect (reduction in capacity when charging an under-discharged battery) and are easy to use, because are equipped with their own control circuits. From the point of view of the average consumer, they have practically no disadvantages, because They are associated with specialized maintenance and long-term storage. The fundamental disadvantage of any built-in battery is the impossibility of quick replacement; The only option is to charge the battery, which sometimes takes a significant amount of time.
— Li-Pol
battery(lithium polymer). In fact, they are a modified version of lithium-ion batteries (see above). They have the same advantages, in addition, they are more compact (from 1 mm in thickness), which allows them to be used in miniature models. At the same time, lithium polymer batteries do not perform well in the cold.
— AA
battery(or several batteries). Powered by a regular AA battery(s), commonly known as “finger-type” batteries. The advantage of such power supply is the ability to quickly replace a “dead” battery: if you have a spare one, this operation is performed in a few seconds, and buying additional batteries in reserve is usually not a problem - they are sold everywhere. The main disadvantag
...e is the need for financial expenses to purchase batteries, while high-capacity ones are expensive, and cheap ones quickly run out. On the other hand, there are rechargeable batteries in the form of AA batteries; If the voice recorder is used frequently and a lot, the purchase of such batteries may well pay off.
— AAA battery (or several batteries). Powered by a battery or AAA batteries, commonly called “pinky”. They are smaller in size than “finger” AA (see above), making them better suited for portable equipment, incl. voice recorders, otherwise completely similar.
— Coin-cell battery. Powered by a replaceable compact battery shaped like a tablet or button. Such batteries are the smallest option available today, which makes it easier to create compact devices for them. In general, they are similar to AA and AAA (see above), but they have a number of differences, except for the actual form. In particular, there is no single standard for “button” batteries - there are a great variety of them, in different sizes and voltages, which can cause difficulties when finding a replacement for a “dead” battery. In addition, they are much less common.
