Transcript
Design of a Crossover Network and Acoustic Characterization of an Audio Loudspeaker Bryant Rivera, Irving Collazo, Yolanda Figueroa Advisors: Dr. Gerson Beauchamp, Dr. Shawn Hunt Electrical and Computer Engineering Department University of Puerto Rico, Mayagüez 1. Introduction
3. Objectives
High fidelity (HiFi) loudspeaker systems require crossover networks to divide the frequency content of the sound among the different drivers: woofer and tweeter. To accomplish a HiFi sound, the crossover network has to be designed and the performance of the loudspeaker system needs to be validated by measuring its frequency response.
§ Develop a methodology to characterize audio loudspeaker systems
Chart 2: Frequency response of the tweeter.
§ Design a crossover network to improve the performance of the loudspeaker system § Acquire automated data using audio systems including microphone, pre-amplifier, data acquisition card, and computer software
Chart 3: Total Frequency response C2 10uF
Circuit a
L2 0.68mH
Tweeter
.
4. Methodology
High-Pass Filter L1 0.8mH
Research
VAC
Circuit b
C1 8.2uF
Woofer
Low-Pass Filter
A first implementation of the second-order crossover.
Design
2. Problem & Hypothesis Problem: The problem is to design, simulate, implement, and validate a crossover network for a high fidelity audio loudspeaker system. To this end we will consider the frequency response of each driver as well as that of the loudspeaker enclosure. We will incorporate the both acoustic models in our analysis and simulation. The loudspeaker performance will be validated using computer programs readily available and data acquisition cards to be acquired. Several crossover network configurations will be considered. Hypothesis: The performance of an audio loudspeaker system can be significantly improved when adequate characterization mechanisms are available.
Program Sponsors:
Equivalent Circuits for Crossover Network: a) high pass filter for tweeter b) low pass filter for woofer
6. Timeline Simulation
Implementation Flowchart illustrating the steps required to achieve the project objectives
5. Preliminary Results
ACTIVITY
START
END
Discuss plan and work
8/18/2014
8/24/14
Buy equipment
8/25/2014
10/5/2014
10/6/2014
10/26/2014
Implement the crossover
10/27/2014
11/16/14
Learn to use the characterization software
11/17/2014
1/25/2015
1/26/2015
3/8/2015
Revise the crossover network
3/9/2015
4/5/2015
Finish presentation for IAP meeting
4/6/2015
Research crossover implementations
Characterize the speaker
4/12/2015
References
Chart 1: Frequency response of woofer.
1. Dennis Bohn, ‘RaneNote 160. Linkwitz-Riley Crossovers: A Primer.’, October 2005 2. S. P. Lipshitz and J. Vanderkooy, "A Family of Linear-Phase Crossover Networks of High Slope Derived by Time Delay," J. Audio Eng. Soc., vol. 31, pp. 2-20 (Jan/Feb 1983). 3. D B Keele, Jr: Low-Frequency Loudspeaker Assessment by Nearfield Sound-Pressure Measurement, 1974-04 AES 4. Leach, Jr., W. Marshall, Introduction to Electroacoustics and Audio Amplifier Design,” Kendall, 2nd. Ed., 1999.
September 25, 2014
