Sub-Woofer Amplifier

1 Project Overview
This project is to design and construct an amplifier specifically for the purpose of driving a high powered subwoofer. There is a large market for home audio with many products available that is satisfactory for most people. But there is smaller group of people who want their stereos to sound the best, with audio quality that typical off the shelf systems can’t provide. And typical component systems run into the thousands of dollars for good sound performance. These audiophiles are who this project hopes to address by creating a low cost high performance amplifier. Products currently on the market for this group are few and are prohibitively expensive for people wanting good sounding equipment without thousands of dollars to spend. The car audio market has many products to offer for this group but almost none of these products have an analog for home theaters. The car audio domain has many amplifiers that can drive subwoofers at high power, but unfortunately they do not run off of 120V wall sockets. A main problem is the small number of sufficiently high power amplifiers specifically for use with subwoofers. There are several full range amplifiers at high power ratings designed for use in concerts or other venues, but full range amplifiers cost more than subwoofer amplifiers and often do not have low pass filters built in, a critical error that could damage subwoofers if not properly addressed before use. A typical high power full range amplifier can run as high as several thousands of dollars, and a low end model can still be in excess of $500. This project intends to construct a dedicated subwoofer amplifier for less cost than what is available on the market for use in home audio systems. This amplifier will be sufficiently high powered and support a wide range of speaker impedances for maximum compatibility. Also, this project will introduce a wireless remote to control power and volume, something not typically found on amplifiers but will add considerable convenience to operate.

2 Needs Identification and Background Research
3 System Requirements and Desired Features
4 Design Solutions
5 Top Level Block Design

5.1 Controller Code
5.2 Controller
5.3 Front Panel Controls
5.4 Wireless Receiver
5.5 Wireless Remote
5.6 Amplifier Block Diagram
5.6.1 Input Stage
5.6.2 Digital Volume Controller
5.6.3 Amplifier
5.6.4 Inverter
5.6.5 Protection
5.6.6 Output Filter
5.7 Power Supply Block Design
5.7.1 Rectifier and Filter
5.7.2 Switching Circuit
5.7.3 5V Output
5.7.4 25V Output
5.7.5 Capacitor Discharge
5.7.6 Fan Circuit
5.7.7 Side Input Rectifier and Filter
5.7.8 Sensor

6 Testing

6.1 TestingDoc

7 Project Timeline
8 Budget
9 Materials Expo Materials

Student names:
Mark Arita, aritam@engr.oregonstate.edu
Michael Rydell, rydellm@onid.oregonstate.edu
Brent Scrivner, scrivneb@engr.oregonstate.edu

Mentor:
Donald Heer, heer@eecs.oregonstate.edu

ECE44x Mentor:
Tim Marr, marrt@onid.orst.edu

References: