Quote:
Originally Posted by
Head Injury 
I trust you've done ABX or blind tests.
Soundstage, from my experience, is far more reliant on the recording than it is on the recording's bitrate.
Yes, I've done plenty of blind tests with my girlfriend doing the switching for me. Once you know what to look for it becomes really easy.
One of the techniques mp3s use to reduce filesize is called Joint Stereo. What it does is that if there's a sound that's similar in both the left and right channels, even if they're at different volumes, it combines them into a single mono sound. Then when it's played back, that mono sound ends up played back either entirely on one side or in the center, depending on what the encoder's threshold was when compressed.
It's also apparent sometimes when a certain sound has a slight delay between channels, which is normally done when the mastering engineer wants to give you the feel that the sound is coming from everywhere (such as you'd get with an audience clapping). That tiny delay is ignored, and it becomes compressed to a mono sound. Sometimes the delay is large enough for the encoder not to pick it up, but most of the time it does happen.
This Joint Stereo effect is always there regardless of the mp3's bitrate. The only time it's undetectable is if you're using improperly set up speakers (not spread out enough, out of phase, room reflections, etc), or if the track doesn't have a detailed soundstage to begin with (as is the case for a lot of Electronic music).
Quote:
Originally Posted by
StargateRecords 
Thanks for posting that, it made me think... and I just had a eureka moment, I listened to a track that I know contains an acoustic guitar that appears to move seamlessly in an arc from left to right. If you close your eyes and point to where it is in the room you could easily say 9, 10, 11, 12, 1, 2, 3 o'clock. I then listened to the compressed MP3 track, and sure enough the acoustic guitar jumps from 9 to 12 to 3 o'clock ! wow, what an insight ! but it doesn't make any sense, could this be something to do with how the track has been compressed ? using Joint Stereo instead of Stereo or Dual Chanel ?
Exactly
Edited by Manyak - 9/9/11 at 7:33am