[Mike Walker]

Coolvij writes "Mike: that is an excellent point - but a waveform doesn't show EVERYTHING, does it? Correct me if I am wrong, but a waveform cannot show soundstage, can it?"

Actually "soundstage" is something that exists only in our minds, just as with "motion" when we watch tv and/or movies. Our senses are being fooled into hearing something (depth/motion) which really does not exist. The cues which SUGGEST depth/positioning/elevation/etc ARE contained within the left/right waveform, and (more importantly) their phase relationships to one another. Note: Some mp3 formats DO NOT retain the left/right phase relationships, and can thus damage the "soundstage" (or "illusion" of soundstage, if you prefer). But the "true stereo" method of encoding DOES maintain left/right phase relationships, and hence SHOULD preserve "soundstage", or the illusion thereof!

(Why do I claim that "soundstage" is not a real thing, but is something we are fooled into believing that we hear? Think about it...with stereo there are two discreet channels which actually have no relationship to one another other than what the recording conveys THROUGH them. The "cues" which lead us to believe we are hearing "layers of depth" are in the recording, contained in varying patterns of amplitude, frequency, and phase. If amplitude, frequency, and phase remain relatively "unscathed" through the encoding cycle, then so should "soundstage", or the illusion thereof)

 

[MacDEF]

Tim: LOL!

Blah, blah, blah, blah, blah. These MP3 debates are so boring

 

[coolvij]

Tim: HEY!!!!!

Mike: thanx for the explanation - bear with me....i kno so little.....

MacDEF: Yea - you're right. you're a mod, aren't you? LOCK LOCK LOCK ........

 

[Odin]

It's a simple fact that MP3 is, more or less, a compresson standard. It reformlates sounds into data, picks out freequencies that you "can't hear" and deletes them from the track. Unfortunately, hi-fi equipment is a little too sophisticated for this compression technique and what results is a loss of quality. It uses the same compression standard as the audio channel in DVD-Video, which is good enough for video, but not really suitable for hi-fi. We are constantly striving to make our sonic reproduction better, not worse, so MP3 simply cannot be a practical hi-fi technology!
I didn't write that, it's from a magazine, it basically argues that MP3 isn't hi-fi technology, and I believe I'm not the only one to believe that

 

[Mike Walker]

As my father used to say, a LITTLE knowledge is a dangerous thing! The technique I used above PROVES that properly encoded high bit rate mp3 changes a signal far less than ANY analog recording technique. Try capturing ANY sound to analog, and doing a null test. Better yet, don't bother. Even the most sophisticated, highest priced analog gear isn't even in the ballpark of being of high enough quality to pass the "null" test. Speed irregularities alone would make it impossible to superimpose one waveform over another.

What exactly is the definition of "high fidelity"? If it is changing the signal which passes through it little, if any, then by definition high bit rate mp3 is "high fidelity", because the "null test" PROVES that PROPER mp3 encoding removes almost nothing from the "uncompressed" original. Have you actually tried the "null test" Odin? It's most enlightening! What remains is ONLY what mp3 removed from the original file. At higher bitrates, with proper encoding, there is either nothing, or almost nothing remaining! TRY IT!

While you're right that mp3 (and other "lossy compression") techniques CAN "remove frequencies" as ONE OF the methods of reducing data consumption, this test proves that with real music signals, at high bit rates, it (removing lots of "frequencies") simply isn't necessary. By the way, selective frequency filtering is only one of the techniques employed!

Also, mp3 is CERTAINLY NOT the technique used for audio on dvds! That is either Dolby Digital, DTS (Dolby Digital is the only audio format REQUIRED for all dvds), MP2 (NOT mp3), or uncompressed PCM. EVERY DVD has Dolby Digital. They may also include "extra formats" mentioned above, as selected by those who create the discs. Dolby Digital, DTS, and MP2 are ALSO "lossy" compression techniques, as are Windows Media, Real Audio, Quicktime, ATRAC, ATRAC3, ADPCM, etc. Lossy compression is EVERYWHERE these days, including on the cds, DVD-As, SACDs, HDCDs, LPs, Cassettes, etc. that you buy in stores, because it is now ROUTINE for performers in different cities (and different studios within those cities) to play together on the same recording, without anyone getting in a plane. This is accomplished by sending audio through ISDN lines, using MPEG AUDIO COMPRESSION of one type or another. Gotcha! I'll bet NONE OF US possess music libraries free of recordings made this way. And you didn't even hear anything, did you? My point exactly!

 

[MacDEF]

To be completely accurate, QuickTime is not necessarily "lossy" nor is it necessarily "compression." You *can* compress audio using QuickTime, but you can also use full, uncompressed audio. It's up to the person doing the encoding.

If you're referring to QuickTime streaming, or the movies you usually download over the web, then, yes, it's compressed audio.

 

[Mike Walker]

Point well taken, MacDef!