This is a portable battery operated little amplifier I built to plug other portable things into and to also use it as a test amp for other projects. The circuit is based on a 5 Watt LM384 mono chip amp, taking a 1/8" stereo jack and resistor summing to a mono output. Giant volume knob, on/off rocker switch with power LED light. 4 Ohm, 6 Watt speaker pulled from an old Creative 5.1 set. Wooden enclosure with a custom designed speaker hole.
For this project, I took some analog VU meters from a broken Otari 5050 2-track tape machine (thanks Ralph!), and assembled a standalone stereo meter unit based on the VU buffer circuit from JLM Audio. I re-purposed a wooden box for the enclosure, drilling holes for the input jacks and meters, and applied a 'tung oil style' finish. As a final touch, I swapped the old meter bulbs with LEDs and added a dimmer knob on the side to adjust brightness.
This was a project done with Anthony Mangognia and Alex Spektor while at the University of Illinois at Urbana Champaign as part of ECE 445. Chad Carlson was our TA.
We designed and built a parametric audio equalizer that allowed a user to boost or attenuate a frequency based on their finger position on a custom built touchpad. By applying downward pressure on the pad, the filter Q/bandwidth would change as well. The advantage over traditional equalizers is the ability to quickly sweep the frequency spectrum in real time to gently or aggressively cut or boost a desired frequency.
The touchpad is a low cost design utilizing only 4 pressure sensors, but allows for three control parameters: X (frequency), Y (boost/attenuation), Z (Q/bandwidth). I was responsible for the digital signal processing portion of this project, and implemented an all-pass Metria-Regalia filter.
This project won the Design Award for the Spring 2005 semester.
I built this speaker switch for Soapbox Music to allow a listener to quickly switch between different speakers. No studio monitors are perfect, and everyone listens to music on different systems, which can make it hard to know if a mix is balanced correctly. I find it very helpful to be able to quickly switch between various speaker systems to compare how things sound.
This box is a passive line level switch utilizing a 5 position, 6 pole rotary switch. It takes two balanced signal inputs and allows you to switch between 5 different outputs. Before we upgraded to an SM Pro Audio Passive-1, we had it setup at the studio with a Blue Sky 2.1 system, Adam A5s, and a FM transmitter to allow playback on a nearby radio. Spray lacquer finish on a wooden enclosure.
