"Pervenche" in this car, the subwoofer was performed on the basis of the Soviet, thoroughly already forgotten heads GD - in the seventies - workhorse domestic electroacoustics. When decent resonance frequency (32 Hz), they had the creepy factor, on the order of 0.8 - 0.9 (estimates vary), so had a fair impact, but much Brokeback frequency response. Yeah what is it, need to get involved, but we'll see (original remarks On s engage, pius on verra owned by Napoleon Bonaparte, to whom the author expresses his appreciation for productive thesis).

The result was a box with a volume of approximately 20 liters, almost rectangular (directed to the rear seat back wall was made with the corresponding bevel), with two heads on the front wall and amplifier, prihvacenim to the side.

The subwoofer is a composite construction made of wood and fiberglass

Authorities suspect this thing is low and willingly, but not very musical, in the sense of explicit predisposition to certain tones and obvious dislike for others regardless of the arbitrariness of musician that these notes were taken.

Some improvement occurred after the alteration in Isobaric design, by install two similar heads (all left). The resulting monster on simochka.

 

The soul, however, has requested another - respect for the musicians, armed with bass instruments. They because something think before you pull the string or press the pedal beater. New subwoofer was designed on the basis of 25 cm heads the firm's a/d/s/. I heard in the original demo car at competitions and I liked. Problems in the design there were two:

  • Get chastotu, consistent with the transfer function of the salon
  • To make the subwoofer, making the minimum interference with the ordinary using the car - or rather, its trunk.
  • The first task was solved by me favorite programs PerfBox 4.5. (The program is on http://www.caraudio.ru/infores/soft/toc.php). The head parameters (Fs = 32 Hz, Qts = 0.3 , Vas = 70 l) clearly indicated the phase inverter, and the size of the cabin - on chtoto cut commercials Hertz approximately 55. The results of the simulation on the chart, for three frequencies settings corresponding to the length of the tunnel from 170 to 250 mm (diameter were taken 75 mm - the minimum for the head).

    The required volume was about 19 l, from which it proceeded. The red line in the chart is for comparison, what would have happened with the same head in the same volume in a closed box. I'll tell you that it is not so easy it was to compare with the actual design, due to some exotic forms.

    Now about the execution. Because machine - hatchback (antique Ford Sierra, I don't spoke?), full use of the advantages of the Luggage compartment may only under the condition that there is no obstacle to fold the seat. In these assumptions eyes fell on the right rear corner of the trunk, and, as a side the surface is not flat, this meant the need for some refinement in the choice of materials and technologies. The dark past of the author included, at some stage, fussing with boats and motor boats, therefore, the appearance of fiberglass and smell unsaturated polyester resins him (me, if you lost the thread) do not scare. And decided to do.

    Thus, the first and most important stage. Bearing in mind the ratio of 7:1 between the measurement and circumcision, for all flat parts, which were supposed to be made of good old chipboard, were made templates of hardboard, which gradually, right at the place in the trunk, were fitted to obtain the maximum conformity, mean absence gaping gaps.

    Then on the obtained patterns were cut all the panels except the rear, facing the wall of the trunk, and the front (this will come later) and connected on all rules - adhesive, screws, bars and scarves podkrepleniya etc.. Details upholstery (two) that had to Wycliffe fiberglass the bottom of the box were ejected from the car and temporarily fixed on the sheet of plywood in the same the relative position they occupy in the trunk.

    Now the main task - to protect them from pervasive resin. Great the material for this purpose is polyethylene film for packaging products. It is thin and sticks to itself, which gives some confidence in the absence of possible places the leakage of the resin, the consequences of which are of the nature of the disaster. After all was closed (in two or three layers - a thin film and forms does not distort), wooden part of the box was put back in place and all joints with padding on the outside sealed red packing tape.

    In the picture you can see the first layer of glass laid on the surface of the protected upholstery playing in this technology, the role of the matrix. When they harden, can peel the tape, pull the drawer out of the upholstery (if you were careful with the separation film. If not, then too to pull outwith a really big damage), put the trim in place and work with a subwoofer enclosure as so. Subsequent layers of fiberglass also glued on the inside of the box to leave the outer surface closely matches the contours of the matrix. Because important in the design of the subwoofer Cabinet - stiffness were used all the tricks the provision of such ribs, simultaneously with wycliffite the wall surface, the gusset plate at the junction of flat side panels, strengthening for the installation of the front panel and mighty intermediate wall connecting the two side Board and back (fiberglass).

    In this genre - not much happens. After all the structure strength and the article will resemble a battleship (not less agree, you can settle down and, before you put the front panel, with already cut the holes under golcu and tunnel (or tunnels, as in my case), cover the entire surface of the inside of vibration-absorbing material. Almost any anti-corrosion coating in a spray can will do.

    After final Assembly of the housing, uneven at the joints and shells (inevitable, alas) on the fiberglass acquires all of the above here is the view (face and back).

    P. S. After polonnoe time ceased his earthly life and the car, but what is interesting cases of the subwoofer is still alive (in a personal Museum of the author), and amplifier Jensen continues his military life, and brings rewards for slaughter the sound pressure levels at the car Sergey Klevtsova.

    Author: Andrew Elyutin; Publication: www.avtozvuk.com, www.cxem.net

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