1 / 19

Design and Construction of a High-Fidelity Audio Loudspeaker System

Design and Construction of a High-Fidelity Audio Loudspeaker System. The Goal: Accurate reproduction of an audio recording. Tweeter Box. Tweeter Driver. Amp. X-over. Mid Box. Mid Driver. Woofer Box. Woofer Driver. Achieving an excellent transient response is very important.

chas
Download Presentation

Design and Construction of a High-Fidelity Audio Loudspeaker System

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Design and Construction of a High-Fidelity Audio Loudspeaker System

  2. The Goal: Accurate reproduction of an audio recording Tweeter Box Tweeter Driver Amp X-over Mid Box Mid Driver Woofer Box Woofer Driver Achieving an excellent transient response is very important.

  3. Driver Selection • Acoustic response • Impedance response • Spectral decay graph • Cone size vs. usable freq range & radiation pattern • Cone material – polypropylene, metal, paper • Spread sheet for listing drivers T/S Parameters and calculating • Box size • Sensitivity / efficiency • Fs, F -3db • Cost

  4. Quality Factor Target Q – 0.577 Q=.707 Butterworth Q=.577 Max flat delay Measured Mid Q=0.69, 0.63 Q=.5 Best Transient Measured Bass Q=0.65, 0.67

  5. Woofer Box Design • Completely damp the back wave restricting it to the interior of a sealed cabinet • Stiffness & Damping • Braces • Steel stiffening supports • Clay interior coating • Large mass • Vb Qsys • High Quality MDF (medium density fiberboard) • Asymmetric positioning of supports

  6. Woofer Box Construction Driver port view Brace w/ Clay Overhead view Back & Baffle Sidewalls w/ epoxied steel reinforcement

  7. Baffle step and baffle shape Low freq radiate into a full space, high freq radiate into a half space Spherical shape produces the best acoustic baffle response

  8. Mid Box Construction Driver Flush mounted Asymmetrically positioned brace Acoustic wave suppression T-nuts Driver offset Driver housing support Binding posts

  9. NI LabView NI LabView Test and Measurement Automated tests were developed to acquire 2000 data points between 10 Hz and 20 kHz. Acoustic Impedance HP Low Freq Impedance Analyzer Signal Gen Amp SPL Meter DMM

  10. Impedance Plots Tweeter Mid Woofer

  11. Woofer Impedance compensation Output Response Mag Output Response Phase ImpedanceResponse

  12. Acoustic Response of each tweeter

  13. Average Acoustic Response of all 3 drivers

  14. Tweeter Impedence & Sensitivity Compensation Output Response Mag Output Response Phase ImpedanceResponse

  15. Third Order X-over Individual DriverResponses ImpedanceResponse Summed Output Response

  16. Crossover Construction 1st and 3rd order both at 450 Hz & 2500 Hz separated by 2 DPDT switches Each impedance correction circuit can be switched in or out of the network Cement anchored copper pads Low DCR 12 gauge inductors

  17. Inductor Quality Loose wound on plastic Tight wound on wood Loose wound on metal

  18. Challenges & Difficulties Crack in midrange box Weak joint Experience tremendous difficulty when machining all three enclosures

  19. Export filter output responses and multiply by the driver response yielding a more accurate simulation of the entire system response Research the quality of my x-over components measuring impedance vs. freq for the resistors, inductors, and capacitors. A deeper study of series x-overs and other minimum phase designs MEMS accelerometer glued to the driver with feedback to measure and control the behavior of the driver. Future Work

More Related