To start off with, let me clarify something: You're asking two completely separate questions. I'll tackle them separately.


Q1) Independent of the artifacts inherent with low-bitrate MP3 compression, how does the quality of the Empeg's audio circuitry itself compare to other consumer audio cicuitry?

A1) The Empeg has excellent audio circuitry. The reproduction of the sound is quite detailed and compares favorably to in-dash CD players costing $500.00 or more, and sounds much better than just about any computer sound card.

There is one issue that's unique to the Mark 1's (i.e., you won't have this problem with the Mark 2 when you get it because they fixed the problem): Ground loops. The Mark 1 used a "floating ground" system, which, if you didn't have things hooked up and adjusted in a certain way, could cause some electronic noise in the very low volume noise floor. What this meant is that the Mark 1's noise floor was higher than many other consumer audio components. Like I said, they have solved this problem with the Mark 2's, so you will get a very low noise floor- probably much lower than your amps' noise floors and definitely lower than the noise floor of your computer's sound card.

Depending on how noisy your car is and the quality of your amps and speakers, the improved detail of the Empeg's audio circuitry (when compared to your home computer's sound card) will allow you to notice MP3 compression artifacts that you didn't notice before. That's what happened to me. I had some 128kbps MP3's that I was satisfied with- until I played them on my car system and could hear them in more detail. I've been slowly going through my collection and re-ripping the more troublesome songs with VBR compression instead of 128k-fixed.


Q2) Independent of the audio circuitry, how does MP3 compression affect the quality of the music?

A2) This has been discussed in detail elsewhere on the BBS. The general consensus is:

- At 128kbps fixed bitrate, most non-audiophile listeners can't tell the difference between the MP3 and the original CD. However, on some songs, certain high-frequency pink noise (like cymbal crashes) will sound "swishy" or "crackly" instead of smooth, as if they were being played from a cassette tape that's wearing out. An audiophile will usually notice these artifacts right away in a blind test. A non-audiophile could be taught to easily recognize these artifacts if given the proper examples.

- At 160kbps, those artifacts start to go away, and at 192kbps and up, even most audiophiles can't distinguish the difference between the original and the MP3.

- Variable Bit Rate encoding allows you to combine the best of both worlds: the smaller file size usually associated with 128k-fixed MP3s, but the higher quality associated with higher bitrate files for the frames that really need the extra boost in resolution. As I mentioned before, I have been re-encoding some of my 128k-fixed files into VBR files and I'm quite happy with the results. You can adjust the VBR quality-to-file-size ratio: the ratio that results in VBR files that are equal in size to 128kbps-fixed files will sound much better than the 128k files.


In the end, combining both your questions back into the original single question:

Provided that I've encoded the songs properly, I can't tell the difference between the MP3s on the Empeg and the original CDs played in a good CD player.

Tony Fabris
Empeg #144