mp3

75 Articles

Know Audio: Lossy Compression Algorithms And Distortion

October 28, 2025 by 37 Comments

In previous episodes of this long-running series looking at the world of high-quality audio, at every point we’ve stayed in the real world of physical audio hardware. From the human ear to the loudspeaker, from the DAC to measuring distortion, this is all stuff that can happen on your bench or in your Hi-Fi rack.

We’re now going for the first time to diverge from the practical world of hardware into the theoretical world of mathematics, as we consider a very contentious topic in the world of audio. We live in a world in which it is now normal for audio to have some form of digital compression applied to it, some of which has an effect on what is played back through our speakers and headphones. When a compression algorithm changes what we hear, it’s distortion in audio terms, but how much is it distorted and how do we even measure that? It’s time to dive in and play with some audio files. Continue reading “Know Audio: Lossy Compression Algorithms And Distortion” →

Unreleased Amiga Hardware Plays MP3s

May 25, 2025 by 35 Comments

The MP3 file type has been around for so long, and is supported by essentially all modern media software and hardware, that it might be surprising to some to learn that it’s actually a proprietary format. Developed in the late 80s and early 90s, it rose to prominence during the Napster/Limewire era of the early 00s and became the de facto standard for digital music, but not all computers in these eras could play this filetype. This includes the Amigas of the early 90s, with one rare exception: this unreleased successor to the A3000 with a DSP chip, which now also has the software to play back these digital tunes.

The AA3000, developed as a prototype by Commodore, was never released to the general public. Unlike the original A3000 this one would have included a digital signal processing chip from AT&T called the DSP3210 which would have greatly enhanced its audio capabilities. A few prototype boards did make it out into the hands of the public, and the retrocomputing scene has used them to develop replicas of these rare machines. [Wrangler] used one to then develop the software needed for the MPEG layer 2 and 3 decoder using this extra hardware, since the original Amiga 3000 was not powerful enough on its own to play these files back.

If you want to follow along with the community still developing for this platform there’s a form post with some more detail for this specific build (although you may need to translate from German). [Wrangler] additionally points out that there are some limitations with this implementation as well, so you likely won’t get Winamp-level performance with this system, but for the Amiga fans out there it’s an excellent expansion of this computer’s capabilities nonetheless.

Thanks to [Andy] for the tip!

Continue reading “Unreleased Amiga Hardware Plays MP3s” →

All-Band Radio Records Signals, Plays MP3s

May 4, 2025 by 10 Comments

In these days of everything-streaming, it’s great to see an old school radio build. It’s even better when it’s not old-school at all, but packed full of modern ICs and driven by a micro-controller like the dsPIC in [Minh Danh]’s dsMP3 build. Best of all is when we get enough details that the author needs two blog posts — one for hardware, and one for firmware — like [Minh Danh] has done.

This build does it all: radio, MP3 playback, and records incoming signals. The radio portion of the build is driven by an Si4735, which allows for receiving both in FM and AM — with all the AM bands, SW, MW and LW available. The FM section does support RDS, though because [Minh Danh] ran out of pins on the dsPIC, isn’t the perfect implementation.