[Patrick] has a pair of Klipsch speakers that continually needed the volume knob cleaned. After a bit of research, he found it was a common problem with the potentiometer chosen for the task. He decided to resolve the problem, not by replacing that potentiometer, but by modifying the speakers to be passive and running them from an external amp. While this does sound simple at first, he wanted to retain the rest of the electronics in the unit, so a bit of hacking was required. You can follow along through the whole process on his site.
digital audio hacks716 Articles
Solid State Tesla Coil
While researching solid state Tesla coils we stumbled across this old project. As you have probably guessed from the pictures, this coil is meant to actually play music. Knowing how to add eye catching flare, the coiler uses a Plexiglas frame turned light pipe; only to be complimented by an audio amplifier complete with graphic equalizer. There is a video of the coil in action on YouTube. We have covered singing tesla coils in the past. Other twists on the classics include the tesla coil guitar amp and a hand held plasm gun.
James R. Knight Memorial Organ
[Jared] wanted to do something monumental to commemorate his late father. His idea was to take this organ console and convert it to a digital beast powered by Hauptwerk software. The project is slated to take 18 to 24 months to complete, at which point he’s going to donate it to his church. You can follow along as he guts it and replaces all the mechanicals with new parts to interface the computer. He also finds that he needs at least 42 individual speaker cabinets to achieve the sound he wants. This thing is massive, we would love to see it in person.
Giant Bulb VU Meter
The latest Inventgeek project is a 12 outlet control box. They decided to demo it using a giant bulb based VU meter. The control box has 12 individual outlets hooked up to two layers of six solid state relays. [Jared] notes that SSRs can be very expensive, but he purchased his on eBay for ~$10 each. Wiring and installation on this project is incredibly clean and they plan on using the control box for future how-tos. The simple audio circuit used for the VU is based on the LM3915. You’ll find full plans on the site or you can watch the overview video embedded below.
Stereo Guitar
[Megatronix] wrote in to show us this pretty crazy guitar mod. He has re wired the pickups to make the guitar a “Stereo Guitar“. Generally, the two pickup locations on a guitar are there to provide tonal variation. You can adjust the influence of each to get the sound you want. [Megatronix] decided to re wire the setup so that one is the left channel and one is the right. Thus providing actual stereo sound from his guitar. This will limit his tonal variation considerably, but should at least serve as a proof of concept. We really want to hear a recording of it in action though.
Doorway Subwoofer
We’ve seen some crazy speaker builds in the past (massive folded horns for example). [DiscoJones] wanted to build a set of speakers that could reach very low frequencies and be very efficient. Instead of constructing a large box, he built a baffle that could be placed in a doorway and use the blocked off room as an enclosure. It has eight 12inch subwoofers, eight midrange drivers, and four tweeters. The speakers are fairly cheap and he built a simple crossover to help them work a little better together. The goal was always deep bass though, so don’t expect very high fidelity from a setup like this.
Adding RDS Decoding To A Vintage Radio
[Edo] wrote in to show us how he added RDS decoding to a radio made in 1957. RDS or Radio Data System is a protocol for data transmission. This allows date, time, artist info, and more to be broadcast along with the music. Its a nice feature that many new cars come with from the factory. [Edo] wanted to add it to his old radio though. He kept the radio stock looking, choosing to use an external LCD to display the data. He has posted the information on where to splice in to add this unit to pretty much any FM radio as well as posting the schematics and source code for the unit itself. Look at the very bottom of the page for the download link, its a bit hidden with the advertisements.