The entire circuit is powered from a very simple regulated +-15V power supply, that is able to deliver about 2 A continuous duty, and at least 6 A on musical peaks. Two three-terminal regulators with power transistors wrapped around them do the regulating job. Here in chile we have a 220 V power grid, but of course feel free to use a transformer with a primary suited for your local voltage. The audio signal enters at U1A, which is a simple voltage follower, delivering the signal to U1B. This operational amplifier is wired as a Linkwitz resonance compensation filter. It has a frequency response that is the exact opposite of the low-end woofer response, thus expanding the low bass coverage into frequencies that fall below the natural resonance, and would be strongly suppressed without the filter.
Click here to download the full size of the above Circuit.
Note that some components are specified at rather strange values. These are the exact values computed to compensate the specific behavior of my woofers in my cabinets. If you don't use the exact same speaker, and the exact same materials and dimensions for the cabinet, you will need to recalculate these values. I used the standard values that come closest to the ones stated here, but again, don't copy this part of the circuit blindly, because it will NOT work properly if your woofer or cabinet are different from mine.
I copied the Linkwitz circuit from an article in the november 1990 Elektor Electronics magazine. It was entitled "Active Mini Subwoofer, part 1", written bt T.Giffard. I suggest you try to obtain a copy of that article. It gives all the necessary equations to calculate proper component values for the Linkwitz circuit, for your specific box and driver.
Now let's go on to the cross-over: Again this is not my own design, but is taken from "Active Phase-linear Cross-over Network" , published by Elektor Electronics in September 1987. It mentions Stanley Lipshitz and John Vanderkooy as designers of this circuit. I just changed component values, but kept all of the basic design.
U2A and B form a fourth-order low pass filter with a cutoff frequency somewhat below 500 Hz. U3A and B are used as an all-pass filter (no frequency limiting action), that has exactly the same delay characteristics as the low pass...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
characters left: