It all started with the fact that my classmate asked me to help him with music in the car. There was a speech about the creation of the subwoofer. Some time passed and he still godevil me.
Housing and dynamics
At home while lying two speakers DN-1-4 it was decided to do a sub on them. The type of box was selected FI, because I consider it the best in respect of quality, giving., and the speaker settings allowed you to choose this type of design. Box trapeziodal shape with beveled back cover, for convenience. Made from 16mm chipboard, around the perimeter bars Hm, glued with white glue and twisted screws. Volume of about 50 liters|, the phase inverter is placed in the middle of the front panel, 75mm diameter and length 30cm|, tuned to 40Hz. The side walls are recessed into the hull about an inch to improve the appearance and easy maintenance Saba, because often the owner will have to take out. Since the sub was decided to do active, in the left sidebar made a hole the size of Hm which is inserted into a plate which is fixed to the power amplifier. Inside the box was glued insulating material, although it should be done, just haven't found anything suitable, and the sub is still not himself did. The box is partially filled with cotton wool. On top of the box are covered with carpet.
Dynamics were slightly modified. Was peeled off the old pilotaxitic cap, because at high power it (in most heads) often produces a very unpleasant and loud click, which is explained by the fact that when the amplitude of the stroke of the dynamics of the cap can not miss much pressure air under it occurs rarefied air and the external pressure bends him inside, then he loudly curved back. Made of 3mm cardboard was cut flat cap of the same diameter as the old and stuck in his place with white glue. Since the new cap is not leaking air then had to do a through hole with a diameter of 10mm at the core of the magnet speakers, unfortunately I do not have time to take a picture.
E-filling
To drive the subwoofer, it was decided not to bother with voltage converters and quickly make the amplifier's already proven me the chip TDA1562Q. Because drivers have the 4ω connect them sequentially (chip does not work on a 2 Ohm load) but in this case the chip clearly lacked power, it was decided to make two amplifiers each of which worked (works) on its dynamic head. Because the radio had a line out for subwoofer, we refuse to use active filter signal processing, and the quality of play| not so much worried about the owner as power.
The switching circuit shown in figure
The printed circuit Board has a size of 50*155mm, there are two completely separate amplifiers. Its in the format of SL4.0 can be taken here.
On the circuit Board are provided for the connection of indicators of inclusion and H-modes on both channels, as well as "soft" inclusion.
To insert the plate is fixed to the radiator where|what| fixed charge amplifiers, connectors for connecting the power input connectors, connector, for the connection of remote switch amplifier, and two led indicators, power indicator and H-mode. On the same panel made fuses.
Panel with amplifiers twisted into the prepared hole in the side panel.
The sound
In short the owner remained comforted. Sub plays pleasant enough and deep bass, creating not bad enough sound pressure level, SPL certainly not to speak but for a simple music lover such Saba enough.
P. S. If the radio is not connected with the processed signal for the subwoofer I advise you all to do the filter and be sure the adder.
Author: Sascha Korchinski, sashakorch [dog] mail.ru; Publication: www.cxem.net