Front bass to your car audio system
"Everyone should benefit, being used in its place". K. Prutkov
Relation to inexpensive components in car audio environment is a touch of snobbery. Yes, with the coolest brands to work easier, tricks are not needed. But this is not a sporting approach. Much more interesting to achieve good results with public components. In terms of propaganda auto sound movement "breadth" is a more effective method, it is necessary to learn from the Bolsheviks. "Peace to the cottages, war on the palaces!".
One of the goals I set when creating this audio system is to prove that the sound does not necessarily require significant investments. The key to success is the correct concept and integrated approach to its implementation. The concept of this installation is a three-band front with full bass, the most broad middle range support tweeters and subwoofer only at the boundaries of the operating range of frequencies. It is an axiom.
Full frontal bass can be obtained only in one case - hull speakers must stand under the seats. Neither option door installation does not provide full play bass attack. Given the existing location of listeners near one of the speakers and transverse propagation of sound waves is compensated for the "tasty" part of the band. The reversal of the speakers in the doors, high "beard" reduce the severity of the problem, but not solve it completely. For this purpose, the radiation of acoustic systems should be directed along the interior, and the most logical is to set the speakers under the front seats in a rigid housing. (Savings - eliminates the problem of vibrationfree and sealing the doors).
The operating frequency band of the mid bass under the seat acoustically capped at a value of 500-800 Hz, and three-way speakers & subwoofers - cruel necessity, and not a fad. In addition, to obtain a good tonal balance and cohesive sound stage, without chaotically moving tools, the frequency of the section of the LF and MF bands need to choose not higher than 300 Hz.
The next point is the placement of the midrange speakers. There are three options: doors, kickpanel, torpedo. Installation midrange in the door only makes sense if the half upright driving position, otherwise the speaker is too close and the sound attached to it. Installation in kickpanel does not have this drawback, but the edge of the soundstage is noticeably lowered. If you edit the scene high mounted tweeters - inevitably "recession" tools in height.
At low frequency WOOFER-midrange is the most promising option would be to install the midrange-speakers in the dash with the radiation upwards. This provides a stable height of the stage. In addition, in this embodiment, it is possible to install the tweeters next to the mid-tones, or even install a coaxial head, realizing the idea of a coherent source. Thus it is desirable to use a head with a paper diffuser - only it provides the most natural sounding midrange. Because paper cones small size is not affected zone effect, the frequency range is possible not to limit the top, which again simplifies the task - don't need a crossover.
Speaking of crossovers. Passive crossovers are so last century. In addition, none of the finished three-way speaker system frequency range 300 Hz no - wind colossal reels and put capacitors on hundreds of microfarads unprofitable, not to mention the fact that for a complex load each amp reacts differently. So for the front of acoustics need to use bi amped, it is not only easier, but also cheaper. Section strips LF and MF/HF is made active filters, isolation bands tweeters passive filter.
This concept was developed long ago and repeatedly tested on the cars of different brands. However, I do not pretentious demo car for exhibitions, and the simple everyday car, which would not be ashamed to show it. Therefore, the key points of the installation must be accessible for review, and the functionality is fully retained. Additional condition - minimal intervention in the design and modest labor costs. Began the search for the car that would meet these challenging conditions.
And this car was the Renault Kangoo. High front seats, perfectly arranged space for speakers in the dashboard, excellent ergonomics. In addition, in this version of the car has no rear left door, so the interior sidewall of the fate intended for the placement of components of the audio system. Spartan trim, metallic elements and fantastic review evoke the cabin of the old bomber. Given my passion for aviation, visual solution installations come immediately, aluminum, panel, shiny bolts. All work performed by their own forces in the garage and do not require high qualifications, and special equipment.
Due to the high ceiling of the vehicle interior has a specific transfer function. In order to neutralize the possible low-frequency resonances, the speaker treble level is set asymmetrically, with different directions of radiation. The right speaker is installed closer to the front edge of the seat cushion and emits a signal up and forward. Left side speaker is shifted to the rear edge of the seat and emits a signal parallel to the floor. First, it is almost equalizes the path of the sound wave to the driver's seat, second - blurs the acoustic resonance.
Low-frequency drivers - domestic DN-4. At all desire to find an adequate replacement has not yet succeeded - despite the richness of the range of the speakers 13 cm head manufactured exclusively in "door" design. Same here used a vented box volume of 7 liters, the tuning frequency of the port 45 Hz (design Oleg Leonov). Housing low-frequency acoustic systems made of particle Board, outside is covered with leatherette. The sides are decorated plates from MDF, painted in black. Each loudspeaker is rigidly connected with the seat frame and moves with it.
Mid-range speakers installed in the standard places torpedo. Paper diffuser provides the most natural sound, but the search for a suitable dynamics were long. Needed a head diameter of 10 cm, with a slight (required paper, not cardboard) diffuser, a sufficiently large stroke and compact magnetic system. The latter condition is dictated by the design of the torpedo. The contest, which was attended by both home and car heads from different manufacturers won Onkyo (regular dynamics KIA). Thanks facing corrugation and dustproof hard cap they confidently reproduce signals up to 10 kHz. Here is another proof that regular speakers are not always bad, you just have to use them correctly.
The tweeters were a kind of casting. With such a wide band midrange is required of them play only the upper part of its range, so the choice fell on the tweeters Hertz with aluminum dome and complete crossover. They are installed on the protective grille on crossexamine scheme, it turned out in fact a point emitter. Sound stage at higher frequencies, is formed by the combination of two signals to be reflected from the glass and scattered signal of the midrange, and the direct signal tweeters. At medium frequencies the scene forms mainly the direct signal of the midrange (directivity in this range is wide enough).
The system uses an amplifier of low class Prology PAS-4100 with minor modifications.(Detail improvements described in the article "Twice amplifier" - "12 volts" No. 56). Changed the crossover frequency of the built-in crossover, the increased quiescent current, sensitivity deliberately reduced (the output of the head unit 2 In). Although the maximum power of the amplifier is 4x100 watts, the power of each channel is limited in the range of 25-30 watts. Large dynamic headroom provides an undistorted reproduction of the pulse signals (pinch the strings, percussion). On live recordings, superbly dispatched the atmosphere of the room.
Although the front confidently reproduce frequencies from 45 Hz to support the bass range, you need a subwoofer. Used active subwoofer Prology AT-1200, it is installed in the trunk and secured with a screw lanyards. Staples for fastening the Luggage in the trunk already and only had to install the subwoofer the eyebolts. To connect the power used by conventional power socket for electric (380 x 40 A). To release the trunk for cargo within a couple of minutes.
Finally, the head unit. I have tried a lot of "heads", and the choice odnodnevnogo DVD Prology DVD-100B is not accidental. The picture quality is very good, but for me that's not it. Compared to traditional CD receivers sound quality of the DVD 100 is immeasurably higher and the ability to view videos a welcome addition for the money. The music on the radio I never listen to (well I can not, can not tolerate this abuse over the ears), so the receiver I is not required. And news in the presence of the TV you can learn without the hassle. (Read more about DVD-100B)
The search for the TV, however, were short-lived. Almost immediately I stopped on the model Premiera RTR-800Z. First, this is the maximum diagonal (8,4'), which can be obtained at a reasonable price, plus a great "picture". Secondly, strict design, logical control, multi-language menu, a good tuner, and even a "Tetris". Thirdly, it was a perfect fit for his seat in the middle of the dashboard. The screen does not cover the review, and at the same time, the driver can always look at him, not looking up from the road. To install, only need to make a bracket ("leg" from the kit did not pass in size). To remove and hide the monitor in "bandaloop" places you in a matter of seconds.
In the supply circuit, the capacitor is installed Prology CAP-1 with a capacity of 1 f, the power wiring is made of cables 4 and 8 gauge (Prology and DAXX, distributors DAXX). In the system single point ground at the negative terminal of the capacitor. Speaker cables - Prology, Oehlbach. The signal cable is self-made, twisted pair screen (Canare). It had to pass before they were able to get rid of the interference of the fuel pump.
Installation of the components does not take a lot of time: everything was prepared in advance. To install the unit in-house interior sidewall replaced with plywood, covered with leatherette in tone to the rest of the cabin. The panel on the perimeter drawn by bolts to the housing, the amplifier is attached to the panel via Usovich nuts.
Control output of the head unit womnen SATURN relay. This allows you to include additional loads (e.g. lighting). After the relay control signal is switched by the switch so that it is possible to work amplifiers:
- The amplifiers are turned off (demonstration video)
- Only the subwoofer (SPL competitions)
- The subwoofer and front speakers (for everyday use)
Retail priceTV Premiera RTR-800Z325$ Head unit Prology DVD 100B169$ Active subwoofer Prology AT-1200149$ Amplifier Prology PAS-410099$ Tweeters Hertz HT18X32$ Midrange Onkyo~15$ BASS HTN-4~20$ Posting~70$ Installation and finishing materials~70$ A TOTAL of949$
there she isPhotographs that are not included in the journal version of the article