Comparison Kenwood KMM-BT304 vs Kenwood KMM-303BT

The number of bands in the radio equalizer.

In this case, the band means a separate part of the frequency range, the volume of which can be adjusted using the equalizer independently of the other parts. The more bands the equalizer has, the more accurately it allows you to adjust the overall sound of the car radio acoustics. However, note that multi-band equalizers are quite difficult to set up, therefore they are recommended primarily for experienced users.

The number of fixed settings (presets) provided in the car radio equalizer.

The presence of such settings can greatly simplify the adjustment: choosing the right preset is easier than manually adjusting each EQ band. At the same time, presets are often selected by the manufacturer for certain genres of music and have the appropriate names — "Rock", "Pop", "Jazz", etc.; this simplifies the task even more. And the more fixed settings in the device, the wider the choice of the user. In some radio tape recorders, in addition to pre-flashed ones, user presets are also provided — they can be programmed in advance and turned on in the same way as the preset ones.

The ability to adjust the high cut without affecting other frequency ranges. Thanks to this, you can improve the overall timbre of the sound by completely removing the high frequencies, if necessary (for example, for a subwoofer). Moreover, this method of adjustment is much simpler than adjusting individual equalizer bands (see above). Typically, this function is combined with bass control (see below).

The presence in the radio built-in DSP — digital sound processor.

Such a processor improves the overall sound quality and provides additional options for its adjustment. One of the most important DSP functions is time correction: it allows you to adjust the acoustics so that the sound from speakers located at different distances from the user reaches it at the same time. Such coordination significantly improves the impression of the sound. In addition, radios with DSP necessarily have a digital crossover (frequency separation) and an equalizer with a fairly large number of bands.

The presence of a processor significantly affects the price of the radio, but in most cases this is a justified payment for the sound quality. But the unequivocal disadvantage of "processor" models is the difficulty in installation and configuration, for this it is best to contact a specialist.

The type of volume control provided in the radio. Rotary knobs, sensors or mechanical buttons are most often used in this role; Here is a more detailed description of each of these options.

— Rotary regulator. The traditional regulator in the form of a round knob, which does not lose popularity nowadays — in fact, it is he who is installed in most modern car radios. Such prevalence, among other things, is due to the fact that the rotary knob is compatible with both digital and analogue volume control circuits — which means that it can be used in devices of any level, from top-end to the most simple and inexpensive. In addition, such a regulator stands out noticeably on the radio panel, so you can even find and turn it by touch, without being distracted once again from the road. The disadvantages of rotary knobs include perhaps some bulkiness compared to buttons and sensors, but this moment is extremely rarely significant.

— Mechanical buttons. Traditional mechanical buttons — more precisely, most often one double-sided rocker button, vertical or horizontal. Unlike the rotary knobs described above, they can only be used with digital volume control circuits; therefore, most radio tape recorders with buttons are advanced devices with extensive functionality and a size of at least 2DIN (or a screen of at least 5 ", for standard models). In such cases, the advant...age of buttons over rotary controls is that the rocker can be made very narrow and install even on a very thin screen frame, while the handle requires a fairly wide additional panel. And if you compare this option with sensors, then mechanical buttons are somewhat cheaper, and you can control them blindly without taking your eyes off the road to the radio panel. On the other hand, the mechanics tend to wear out with use, making it less reliable, and many users simply don't like buttons more than sensors, and for these reasons, and a few others, this option is relatively rare.

— Touch buttons. Controls in the form of sensors that are triggered not by pressing, but by touch. Like mechanical buttons (see above), this control is only compatible with digital volume control and is mainly used in advanced radios with large screens. At the same time, the sensors give the device the most advanced and “technological” appearance, attractive to many users from a purely aesthetic side. The main disadvantage of this option is that the touch buttons usually do not protrude from the panel — so it is almost impossible to find the right sensor blindly, and when controlling the radio, you inevitably have to be distracted from the road. However, with more or less decent driving skills and due care, this moment is not a serious drawback, so this type of control in high-end radio tape recorders is used much more often than traditional buttons.

— Remote control. The radio has a remote control. This function will be convenient primarily for passengers behind the driver — from the rear seats you can’t reach the radio itself. In addition, remotes often have more keys than the stock control panel, which allows you to access various additional functions on the go without digging through the settings.

— Remote control on the steering wheel. Remote control (see above) with the ability to mount on the steering wheel. Such a remote control allows the driver to control the functions of the radio without removing his hands from the steering wheel and thus not being distracted from driving the machine.

— Control from regular steering wheel buttons. The ability to control the radio from standard buttons, originally provided on the steering wheel for this very purpose. This function is similar to the steering wheel remote control described above, with the adjustment that the "remote" in this case is built directly into the steering wheel. Before buying such a radio, you must definitely check its compatibility with a particular model of car.

— Smartphone control. The presence of software (application) that allows you to control the radio using a smartphone, tablet, etc. This is not just about switching songs on the phone, but a full adjustment of all device functions.
...
— Voice control. The ability to control the radio using voice commands. The implementation of such control can be different: in some models, to activate it, you need to press a button, others constantly “listen” to the environment and immediately respond to code words. Anyway, this function allows the driver to control the radio without taking his eyes off the road, which has a positive effect on traffic safety. Note that in its pure form, voice control in modern radio tape recorders is becoming less and less common, being replaced by advanced technologies like CarPlay and Android Auto (see “Control Functions”), which also include voice functions.

— Apple CarPlay system. Support for car radio technology CarPlay. This technology is designed to connect portable devices from Apple to the radio, primarily the iPhone, although it is technically possible to work with any “apple” gadget that has iOS 7.1 or later firmware, as well as a proprietary 8-pin Lightning connector. Thanks to this technology, many smartphone functions (including the Siri voice assistant, navigation, call and message management, as well as music) are integrated into the radio; using them through on-board electronics can be much more convenient than holding the iPhone in your hands. At the same time, CarPlay puts special emphasis on safety: it is designed with the maximum use of voice control, so that the driver has to be distracted by the radio screen as little as possible. For example, the mentioned messages can be dictated by voice and listened to "performed" by Siri. The connection itself is carried out by wire, through the mentioned Lightning connector.

— Android Auto system. Car radio support for Android Auto technology. Similar to the CarPlay described above, this technology is designed to combine portable devices with on-board electronics of a car — only, as you might guess from the name, in this case we are talking about gadgets running the Android OS. When you connect such a gadget, the radio actually plays the role of an external display for a mobile device, with its optimized interface and related capabilities. Features available through Android Auto include navigation (including mobile device access to external GPS antennas and modules), music control, receiving and making calls, listening to and composing SMS, and searching the Internet. Android Auto is only available for Android 5.0 Lollipop and later; in addition, if the mobile device uses proprietary firmware, its compatibility with the radio needs to be specified separately.

The number of line outputs (see above) provided in the design of the radio. It should be noted that usually these outputs use RCA connectors (“tulip”), and the analog format allows only one audio channel to be transmitted through one such. Therefore, to work with a stereo signal, two RCA connectors are required, and just a pair of such jacks is considered to be one line output - a set designed for one set of stereo speakers. The main difference between this interface and the same RCA used to connect speakers (see above) is that the line output receives a signal from a preamplifier that is unsuitable for feeding to passive acoustics. Such a signal must be sent to active speakers or an external amplifier (whereas the speaker is connected to the output of a power amplifier designed for passive speakers).