Most of the projects described in this section of the website are based on projects found at Elliot Sound Products
My plans currently involve the construction of a 5.1 system featuring a surround sound decoder to enable all channels even if the source material is limited to a stereo signal. Each of the five channels will be built using bi-amplification. The benefits of such a system are described here. Lastly, an active subwoofer channel will be implemented to maximize the response of the system within the audible bandwidth.
To date, I have completed the construction of the subwoofer. Unlike conventional designs, this speaker is designed to operate below the resonance of the speaker box. Such a design is not generally used because the speaker box effectly acts like a high pass filter. In the design I have implemented, this characteristic is exploited by including an integrator circuit before the amplifier. The speaker box was designed to have a resonant frequency of 60Hz and the integrator circuit was designed to have a 3db freqency of 20Hz. When combined, the entire system has a bandpass response between 20Hz to 60Hz. Although my final design was only able to reproduce signals as low as 26Hz without distortion, I am still quite pleased with the final results. As you can imagine, the downside to this design is that the lower freqencies (20Hz - 30Hz) experience a great deal of gain. In order to accomodate such large signals, a 300W power supply is required to operate this system. I suspect that I am experiencing distortion at 26Hz due to power supply limitations. In the future, I will investigate the effects of improving my power supply.
I will provide more details as these projects progress.