Comparison Olympus DM-720 vs Olympus DM-3

The built-in microphone type determines the mode (number of channels) in which the voice recorder records sound.

— 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.

— 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.

— MP3. The most common digital audio format today, supported by the vast majority of digital audio devices, regardless of size. Provides medium quality compression and medium sound quality. When saved, it compresses information with loss of quality, but these losses are almost imperceptible to the ear, especially when recording speech from a non-specialized microphone.

— WMA. Format developed by Microsoft. It surpasses MP3 in terms of data compression capabilities, providing good quality at a low bitrate and, as a result, a small file size, but is less popular, in particular, due to sensitivity to errors in the file. At the same time, it is very common in digital audio equipment, it can be reproduced on computers without problems (it is a standard audio format of Windows OS).

— WAV. Technically, it is not a format, but a "container" into which you can "pack" sound processed by any codec; however, it is most commonly used to store uncompressed PCM audio. Thus, WAV provides the best sound quality comparable to Audio CD, however, such files, usually, take up much more space than in the above-mentioned formats. It also plays on a computer without any problems.

— Own. Some voice recorder models record audio in their own format, which is different from common standards. Technically, a proprietary format can provide a good r...atio of recording quality to file size, however, listening to such materials often causes inconvenience: you either need to listen to it on the recorder itself, or install a special player or codecs on your computer, or convert it into one of the "generally understood" formats with possible quality loss.

The higher the amount of data per unit of time that is used to transmit the audio stream, the higher the quality of the MP3 recording is provided. So, the base bitrate of 32 Kbps means encoding one second of sound using 32 thousand bits of information - it is used only for speech transmission. Much more common in portable audio recording devices is the recording quality of 128 Kbps, 192 Kbps and 256 Kbps. The maximum possible bits rate for the MP3 format is 320 Kbps. The pursuit of the highest quality of sound recording makes sense for advanced models of recorders; for a conditional voice recorder for recording lectures, the basic bitrate parameters will be quite enough. Also keep in mind that the quality of sound recording affects the size of the resulting files and the duration of the voice recorder.

Uncompressed WAV provides the best sound quality among common Hi-Res audio formats. Its sampling rate is usually 96 or 192 kHz with a bit depth of 24 bits. The format is used for "clean" sound recording with maximum detail of the scene.

The maximum number of folders that can be created in the recorder's memory to store recorded materials. This allows you to organize the materials and makes it easier to find the right record: for example, in journalistic work, the material on each individual topic can be stored in the appropriate folder. Many voice recorders allow you to change the folder used for recording on the fly, literally at the touch of a button.

The range of sound frequencies that the recorder is capable of perceiving and recording. A person is able to hear sound on average from 16 Hz to 20 kHz, but the range of the actual human voice is much narrower — approximately 100-3500 Hz. Therefore, if you plan to use a voice recorder to record speech, these frequencies will be enough. If the purpose of the recorder is not limited to this, you should pay attention to models with a wider range — and in this case, the wider it is, the fuller and richer the recording will be.

— 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.