The MP3 audio file format: Warning! Do not use for serious audio.
Now that I am in the last stage of optimising the new Monitor 40.1 (provisional name) the prototypes have taken on an identity of their own, slinently awaiting my next visit to the Cottage R&D centre where I play all end every type of music on them to try and catch them out. Thus far, they're still smiling - I can't.
When auditioning speakers as a designer rather than listening to music for pleasure, I only need to listen for 30 seconds or so to track as I have in my mind an impression of how the track should sound. A brief listen is enough to compare what I hear with my mental memory - then move on to the next snippet. The objective is not to fall head over heels in love with the speakers but to retain maximum objectivity listening, as it were, to avoid the equivalent of continuous eye contact with a pretty girl across the room.
Anyway - rather than handling a pile of CDs some of which are at home, some at work and some in the Cottage I thought I'd rip the favourite torture tracks onto one CD. That was easy, but by the time I'd finished I'd enough to (unsurprisingly with hindsight) fill three CD's which I burned. As my new CD player advertises the ability to play MP3s from a data CD (not tested) I used the inbuilt converter within Nero burning program to convert a selection of files from .WAV to MP3 and burned a data CD with the MP3s.
When I arrived at the Cottage I dropped the MP3 disc into the CD player and to my slight surprise it found the folder and stated to play. Forgetting that I was playing the MP3 disc I was immediately disturbed by the sound - dirty, completely devoid of ambient detail, compressed, airless and with a narrow mono-like sound stage. I initially thought that I had damaged the system or speakers and checked everything until I belatedly recalled that I was listening to the MP3 disc. I replaced it with the .WAV disk. The difference in audio quality was immense: shocking in fact. The original .WAV files had air and detail, and the stereo huge and wide. I swapped the discs several times with the same conclusion. I had no idea that MP3 could sound so terrible.
I subsequently checked the MP3 disk in the PC. When I made the WAV to MP3 conversion I thought that I had selected 320kb (the highest bit rate for MP3 hence highest quality) and turned on Variable Bit rate so that the MP3 encoder concentrates its efforts on the hard to encode music details. It now seems that the encoder ignored my 320kb setting and these tracks are encoded at between 120 and 144kb. Also, the encoder without asking turned-on the 'joint stereo' option which seems to collapse the stereo spread.
Whether the encoder can be forced to make a .WAV to MP3 conversion at 320kb I don't know, but I can say for sure that down at 128kb MP3 is totally unacceptable as a quality audio format if you are listening on Harbeth speakers with their high resolution. If you are archiving your precious audio recordings to MP3 carefully check that the encoder is following your settings. Better still, don't use MP3 at all for quality audio.
I think that i'll investigate DVD-Audio authoring tools as this, I understand, can hold a high quality better-than-CD sound track.
Alan A. Shaw
Harbeth Audio UK