Comparison Trust GXT 232 Mantis vs Trust GXT 242 Lance

Directionality describes the ability of a microphone to pick up sounds coming from different directions, more precisely, the dependence of sensitivity on the direction from which the sound comes.

— Unidirectional. As the name implies, these microphones are capable of picking up sound coming from only one side. Note that the coverage area itself can be quite wide, but anyway it is located “in front” of the microphone. Unidirectional models are very convenient for the perception of sound from a single source, with maximum clipping of ambient noise.

— Bidirectional. This term in our case means two types of microphones. The first option is the classic bidirectional models, designed for the possibility of normal perception of sound from two opposite sides — roughly speaking, "front" and "rear"; at the same time, dead zones are formed on the sides, from where the sound is practically not perceived. This format of work can be useful, for example, for broadcasting a dialogue in a radio station studio, or when simultaneously recording two voices on one microphone. The second variety is microphones with a pair of capsules directed at an angle to each other (most often perpendicular); a similar design is used in models with a stereo recording function.

— Omnidirectional. Also, this variety is called "non-directional", which also to a certain extent ch...aracterizes its features. Such microphones do not have a clearly defined directionality — they perceive the sound coming from any direction with full sensitivity. An example of a situation where this format might be useful is a recording of a roundtable discussion.

Note that while most microphones only work in one directional pattern, some models support multiple directional patterns, with the ability to switch between them as desired by the user (see Features/Characteristics). The methods of such switching can be different: in some models it is enough to move the switch, in others you need to change the capsule.

The polar pattern of a unidirectional microphone (see above). There are models with DN switching.

By itself, such a diagram is a graph of sensitivity versus direction, built in the so-called polar coordinate system. For unidirectional models, there are three main options for the shape of the line on such a chart:

— Cardioid. A chart shaped like an inverted heart symbol (hence the name). Microphones with these characteristics cover a fairly large area in front, which makes it difficult to filter out extraneous sound sources that are close to the main source. At the same time, they are completely insensitive to sound coming from the rear.

— Supercardioid. These mics have a narrower front coverage than "classic" cardioid mics, making it easier to pick up directional sound. The downside of this is some (albeit rather low) sensitivity to sound coming directly from behind.

— Hypercardioid. The hypercardioid pattern further narrows the microphone's sensitivity zone in the front (compared to the supercardioid pattern), but widens this zone in the back.

Microphone AC impedance; this parameter is also called "impedance". This is one of the most important characteristics that determines compatibility with the amplifier or other device to which the microphone is connected: if the impedance is not optimal, there may be a loss in signal power. It has its own characteristics, depending on the purpose of a particular model (see above). So, for microphones used with computers, laptops, voice recorders and phones / tablets, the impedance may not be indicated at all — the characteristics of such models are selected in such a way as to ensure normal compatibility with the corresponding devices. But in professional audio equipment, special rules are used for selection; more details can be found in special sources.

The range of audio frequencies normally perceived and processed by a microphone.

The wider this range — the fuller the signal, the less likely that too high or low frequencies will be missed due to the imperfection of the microphone. However, in this case, it is worth considering some nuances. First of all: a wide frequency range in itself does not guarantee high sound quality — a lot also depends on the type of microphone (see above) and its frequency response, not to mention the quality of other components of the audio system. In addition, a large width is also not always really necessary. For example, for normal transmission of human speech, a range of 500 Hz — 2 kHz is considered sufficient, which is much narrower than the general range perceived by the human ear. This general range, in turn, averages from 16 Hz to 22 kHz, and also narrows with age. Do not forget about the features of the equipment to which the microphone is connected: it is hardly worth specifically looking for a model with an extensive range, if, for example, the amplifier to which it is planned to be connected severely “cuts off” the frequencies from above and/or below.

Sensitivity describes the signal strength at the output of a microphone when it processes a sound of a certain volume. In this case, sensitivity means the ratio of the output voltage to the sound pressure on the membrane, expressed in decibels. The higher this number, the higher the sensitivity. Note that, as a rule, values in decibels are negative, so we can say this: the closer the number is to zero, the more sensitive the microphone. For example, a -38 dB model outperforms a -54 dB model in this parameter.

It should be borne in mind that high sensitivity in itself does not mean high sound quality - it only allows the device to “hear” a weaker sound. Conversely, low sensitivity is not an unequivocal sign of a bad microphone. The choice for this parameter depends on the specifics of the application: a sensitive device is useful for working with low sounds and in cases where it is necessary to capture the smallest nuances of what is happening, and a “weak” microphone will be convenient at high sound volume or, if necessary, filter out extraneous weak noises. There are models with sensitivity adjustment(and for models with a headphone output , headphone volume control may be provided).

The maximum sound pressure perceived by the microphone, at which the harmonic oscillation coefficient does not exceed 0.5% — in other words, the highest sound volume at which no noticeable interference occurs.

The higher this indicator, the better the microphone is suitable for working with loud sound. Here it is worth considering that the decibel is a non-linear quantity; in other words, an increase in volume from 10 dB to 20 dB or from 20 to 40 dB does not mean a 2-fold increase in volume. Therefore, when assessing, it is most convenient to refer to comparative tables of noise levels. Here are some examples: a level of 100 dB roughly corresponds to a motorcycle engine or subway car noise; 110 dB — helicopter; 120 dB — the work of a demolition hammer; 130 dB, comparable to the sound of a jet aircraft taking off, is considered a pain threshold for a person. At the same time, many high-end microphones are able to work normally at a sound pressure of 140 – 150 dB — and this is a noise level that can cause physical damage to a person.

A parameter that describes the relationship between the useful signal level and the noise level produced by the microphone. Note that the actual signal-to-noise ratio varies depending on the sound pressure perceived by the microphone. Therefore, in the characteristics it is customary to indicate the option for a standard situation — at a sound pressure of 94 dB. This allows you to compare different models with each other.

In general, this indicator quite clearly characterizes the quality of work of a particular model, since it takes into account almost all significant extraneous noise that occurs during operation. The greater this ratio, the clearer the sound is, the less distortion it has. Values of 64 – 66 dB are considered quite decent, and high-end microphones provide performance of 72 dB and higher.

The sampling rate of the analogue-to-digital converter (ADC) provided in the design of the microphone.

An ADC is a module responsible for converting an analogue signal coming from a microphone capsule into a digital format. It is used mainly in models connected via digital interfaces — for example, USB (see below) — and also in some wireless ones, where the digital format is used for radio communication.

The principle of analogue-to-digital conversion is that the analogue signal is divided into separate fragments, each of which is encoded with its own numerical value. If this is depicted graphically, then the graph of the analogue signal looks like a smooth line, and the digital signal looks like a set of “steps” close to this line. The higher the sampling frequency, the more “steps” fall on a certain section of a smooth line and the more accurately the digital signal corresponds to the original analogue.

Thus, high values of this parameter indicate a high quality of the microphone. However, it must be said here that for normal restoration of the original signal from digital (in other words, for normal reproduction of the sound perceived by the microphone), a sampling frequency twice the maximum frequency of the received sound is considered sufficient. For pure human speech, indicators of 2.3 kHz are considered record-breaking, and harmonics that complement the timbre of the voice do not exceed 8 kHz in frequency. Thus, a high sampling rate...is not required for normal speech processing. At the same time, models intended for studio recording (see "Intended use") may have rather high values of this parameter — up to 96 kHz inclusive. This is due not only to the sound quality (although it is also important), but also to the technical aspects of processing and mixing.

Also note that upsampling affects the amount of data transmitted, so high performance is not always optimal. Thus, some microphones allow you to change the value of this parameter; for such models, our catalog indicates the maximum value of the sampling rate.

The bit depth of the analogue-to-digital converter (ADC) installed in the microphone.

An ADC is a module responsible for converting an analogue signal coming from a microphone capsule into a digital format. It is used mainly in models connected via digital interfaces — for example, USB (see below) — and also in some wireless ones, where the digital format is used for radio communication. For more information on this conversion, see ADC Sampling Rate. But if the sampling rate describes the number of “steps” of a digital signal in a certain area, then the bit depth determines the number of signal level options available for each individual step. The higher the bit depth, the more such options and the more accurately the digital signal level will correspond to the analogue level.

Thus, this parameter also directly affects the quality of the conversion. If we talk about specific values, then 16 bits is considered quite enough for professional studio microphones (see "Intended use"), and high-end models can also have 32-bit converters.