hi-fi Loudspeakers plans


Posted on Apr 5, 2012    4561

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.


hi-fi Loudspeakers plans
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...




Leave Comment

characters left:

New Circuits

.

 



Top