Experience with car DVD player

Encyclopedia of radio electronics and electrical engineering / Audio equipment

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Unlike all other mobile DVD players, the Prology DVD-100B is a disc head unit. The external dimensions of the case, the design of the panel, the mounting method fully comply with the DIN standard. At the same time, it remains "just a player", and does not climb into DVD-receivers or multimedia centers. From the point of view of audiopurists - solid pluses, there is nothing superfluous. From the point of view of the "dolphin breeders" - the view is conservative-classic, there are few buttons, there is nothing to even look at. I belong to the first camp, so the choice of the device (I immediately liked it) was far from accidental.

The sound quality is an order of magnitude higher than traditional CD-MP3 receivers of a similar design level. Design and execution are top notch. Therefore, I decided not to limit myself to "bench tests". The best test of any product is trial operation, so the player worked in a car for a month, in real conditions. During this time, more than 5000 km have been traveled along the roads of Moscow and the Moscow region, dozens of discs of all formats supported by the player have been listened to and watched, several TVs and monitors have been tested at the same time (more about them another time). The DVD-100B test results confirmed that I made the right choice.

What is not there?
• No receiver (and why is it needed with a good phono / video library)
• No analog tone/balance/fader controls (sound is ruined)
• No built-in amplifier (and no need, if there is an external one)
• No information board (only create interference)

What is
• 24-bit DAC
• There is a built-in 5.1 decoder (6 analog outputs with a voltage of 2 V)
• There is an output for connecting an external decoder (and the internal one is not bad either)
• There is a built-in volume control (pure math, nothing analog)

In other words, there is nothing that would interfere with the sound reproduction process, but there is only what is needed. The perfect player. And if one signal source seems not enough, then there are two more AV inputs. One input (operational) is located on the front panel, the second - on the back. In addition to it, there are video outputs, analog and digital audio outputs on the rear panel. All connectors are RCA.

How it was tested

The player is installed in the instrument panel instead of the head unit. Fastening - standard, using a frame-clip from the kit. The rear part is fixed with a pin with a rubber shock absorber cap and enters the regular trap hole on the heater body. Nothing original, but tough and reliable. The position is strictly horizontal.

The body of the head unit is electrically isolated from the ground (the instrument panel is made of plastic). The power is organized according to a two-wire circuit (without mass), the voltage is taken from the terminals of the buffer capacitor (as part of the installed audio system). The signal to the amplifier is fed by a shielded twisted pair, the shields are grounded at one point. To view the image used liquid crystal panels with a diagonal of 8 inches. The connection of the entire system to the machine body is from the negative terminal of the buffer capacitor, there are no additional grounding points.

The results

The test carried out pleased with the results. First of all, I was struck by the excellent vibration resistance in the audio CD playback mode. A bumpy dirt road and a broken, as after a bombing, asphalt highway are equally indifferent to the player (at the speeds allowed for these roads). Single strikes also did not cause any consequences, even at a decent speed. The hardest test was rolled large gravel. At a certain speed of movement along such a road, the frequency and amplitude of vibrations exceeded the critical threshold and failures began.

The device does not tolerate overwritten audio CDs. The critical vibration level for them is much less, so there are no failures only when driving on a good road. However, for "self-cut" CD-Rs and even CD-RWs, the resistance turned out to be very high. The sound quality is beyond praise. By the way, it is not necessary to finalize discs: "unfinished" discs are read in the same way as closed discs.

All of the above applies specifically to standard audio CDs. Playback of "packaged" formats (Video CDs, still images in JPEG format, and MP-3 audio recordings) does not appear to be prone to glitches at all (maybe if you try hard enough you can get it, but I felt sorry for the suspension). Long live read-ahead and buffer memory! The audio quality of compressed formats turned out to be surprisingly quite decent, it does not cause fatigue and irritation (as it often happened to me with MP-3). Previously, I was an ardent opponent of this format - but, apparently, so far I have come across the "wrong bees".

Initializing an audio CD after loading takes about 5 seconds, for file organization discs it takes a little longer, while the list of directories is read and parsed. The search for the desired fragment is quite fast. For file organization disks, playback starts from the root directory, then moves to folders. If the root directory is empty or does not contain files of supported formats, then to start playback, you will need to select the desired folder and file through the menu. After the files of one folder are over, there is an automatic transition to the next. When you turn off the power, the playback position of the audio CD is memorized, and the next time you turn it on, it will continue from the same position. However, for some reason this is not always true for Video CD, but I did not investigate the reasons in detail: there is no special meaning, the format is dying out.

During the research, an interesting undocumented feature was discovered. If you place graphic information (for example, a photo) in the root directory of an MP-3 disc and turn it off in the navigation menu settings (SMART NAV - MENU OFF), then after the last (or only) picture from the root directory is displayed, MP-3 files will start playing . Now such a disc will delight not only the ear, but also the eye. Taking the idea further, you can make slideshow presentations by placing JPEG and MP-3 files in the right order. This is of little use to ordinary life, but for demo cars and competitions it is an excellent way out. Since there is no display in the player, all service information is displayed on the screen of the video monitor. Despite the seeming inconvenience, with some skill, the absence of an information board does not prevent you from controlling the playback process "blindly", but it is still more convenient with a monitor. In addition, most discs can use the OSD function (On-Screen Display (OSD) that is separate for discs of different formats).

During operation, the video signal from the disk can be output simultaneously to two monitors via composite video outputs, the video signal voltage is standard - 1 V at a load of 75 ohms. In the course of the experiment, both outputs were used, no mutual influence was found. A study of the editing showed that everything is fair - a separate video buffer amplifier for each output. The video signal path works in NTSC / PAL television color systems with automatic or manual selection, and it is possible to transcode the signal from one system to another. You can select two normal 4:3 formats (PanScan and Letter box) and 16:9 widescreen (Wide) for the "picture" displayed on the monitor. In addition, there is an increase in the size of the image (ZOOM) with the possibility of scrolling.

Thanks to the 10-bit video DAC, the picture quality in all modes is very good - the horizontal resolution is no worse than 500 lines. The image is distinguished by good clarity and color reproduction, not only for DVD, but also for Video CD. For JPEG still images in ZOOM mode, clarity is determined by the resolution of the original image. However, the color balance of the image recoded to the PAL standard is clearly worse, with a predominance of red tones. The same can be said about JPEG pictures. Forcing the video output and monitor to NTSC 3.58 has improved the situation considerably. Apparently, the problem is in the initial difference in standards. PAL suffers from color quality, but is well protected from interference (which is important for on-air broadcasting). NTSC is characterized by low noise immunity (more suitable for cable broadcasting), but it provides the best picture quality. Control of the player in all modes is convenient and logical. It is carried out both from the front panel and from a fully functional complete remote control with a remote IR receiver. A number of functions (eg direct track selection, repeat, cues) are available only from the remote control. Duplication of control functions in a car is very convenient - not only the driver, but also any passenger can control the player. Although in my version the placement of the player turned out to be so convenient that I practically don’t use the remote control - it’s easy to reach the necessary control buttons with your finger without releasing the gear knob (from 1-3-5 gears).

Summing up, I want to say that the Prology DVD-100B pleasantly surprised me - the quality of work and capabilities turned out to be much higher than one could expect for a budget category device, even after reading the instructions. This is another confirmation that the era of "barn production" is over, and the cost of products is now determined not by cheap unskilled labor, but by the degree of automation of production. High-tech products, by definition, cannot be of poor quality.

Author: A. Shikhatov; Publication: bluesmobile.com/shikhman

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