Comparison Olympus DM-720 vs Olympus DM-620

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.

— Change microphone sensitivity. The ability to change the sensitivity of the microphone allows you to optimally adjust it to the surrounding conditions. So, with a low level of extraneous noise (for example, at a lecture or a press conference), sensitivity can be set to the maximum in order to guarantee that everything that is needed is recorded, and in a noisy environment (for example, an interview in a cafe), on the contrary, it can be reduced in order to reduce outsiders noise to a minimum.

— Change the quality of the recording. Possibility to change the recording quality (usually the bitrate of recorded materials). The volume of the file is directly related to the quality: the higher the quality, the more space the recording takes up. Thus, this function allows you to achieve the optimal balance between sound and memory occupied: for example, for loud intelligible speech without extraneous noise, you can use low quality, in a noisy environment, on the contrary, increase it in order to achieve maximum intelligibility; if there is not much memory left, and nothing can be deleted, lower the quality of the recording, etc.

— Voice activated recording. When using this function, the recorder only records when its microphone captures a significant level of sound — in principle, this can be any source, but since human speech is most often recorded, the name of t...his function refers specifically to the voice. With such a recording, the recorder does not record long pauses, which saves both the occupied memory and time (and sometimes nerves) when listening to the recording. The disadvantage of this feature is that activation takes some time and the first sounds may not be recorded on the recording.

— Setting record labels. Ability to assign a unique label to each file. This can be either a number or a time and date, or both. Tags organize entries and make them easier to access, making it much easier to find the right file.

— Recording timer. The timer allows you to set the start time of the recording; when it occurs, the recorder will turn on automatically. Thus, you will be able to record the material you need (for example, a speech or a lecture) from the very beginning, even if you will not be there by the time you start.

— Ring record. The name of this function comes from its resemblance to recording on a magnetic tape closed in a ring. In this mode, the recorder can record regardless of the amount of free memory: new materials are simply recorded instead of the oldest ones. This eliminates the need to clear memory manually and can come in handy if your records quickly become out of date — for example, if you have to take surveys by phone and process the results on the same day. At the same time, this function requires caution, as increases the likelihood of accidentally erasing necessary, but old records.

— Connecting to a computer. The ability to connect the recorder to a computer, usually via a USB interface. Such a connection can be used to save recorded data on a computer, update the recorder's firmware, and some models allow using them as USB drives and even card readers (if there is a slot for memory cards, see above).

— Smartphone control. The ability to control the device remotely from a mobile device. First of all, the function is necessary for recorders that can be installed out of reach of your hands and any movement, pressing a button on the case can adversely affect the recording. But at the moment some new hit can be written.

— Lock buttons. The lock prevents the voice recorder from reacting to accidental button presses — for example, when carrying in a tight pocket or purse with a lot of things. By turning it on, you don't have to worry that accidental contact will start recording and drain the battery, erase files, etc. This feature is usually turned on and off by a slider, by pressing multiple buttons at the same time, or in some other way that eliminates the possibility of accidentally unlocking.

— MP3 player. The ability to use the recorder as an MP3 player to listen to music. Technically, almost all models with MP3 support have this capability (see “Recording Format”), however, some voice recorders have a separate “Player” pro...gramme mode that makes listening more convenient. Typically, the player function requires a headphone output (see below).

— FM tuner. The tuner allows you to use the player as an FM receiver — in this range today the vast majority of music radio stations broadcast. Some models with a tuner have the function of recording from the air.

— Built-in speaker. On the voice recorder with its own speaker, you can listen to recorded materials without using additional equipment (headphones) or connecting to a computer. It can also be used to play music and FM radio (if available); however, the sound quality of such a speaker is usually not high, and its main purpose is to listen to the actual recordings.

— Headphone output. A connector that allows you to connect headphones to the recorder. Their purpose is generally similar to the built-in speaker (see above), however, the sound quality of even inexpensive headphones is often significantly higher. As a result, it is quite possible to comfortably listen to not only recordings, but also music, radio programs, etc. through headphones. (if available). In addition, headphones are well suited for noisy environments. even open models still provide some sound insulation.