Phase Inversion

They do it because they would have to add another amplifier stage to correct it. Most feel simpler is better and it is definitely cheaper.

Yes, it is audible. Simple example: A whack on a bass drum causes the membrane on the drum to move out intially and then it returns. This causes a compression of air followed by a rarefaction. If your woofer incorrectly reproduces this by first moving in and then out it will sound different.

Some (most?) sudios don't pay any attention to this so some recordings end up being reversed.

FYI, the correct term is inverted polarity, not phase. It is confused by the fact that many manufacturers use the incorrect term.

Atagi,
Consider 'phase inversion' as 'nature of the beast' or 'less is more'. Electricial engineers have always had this quandry when designing audio equipment. Most have added the additional phase to 'bring' the positive and negative 'back' so people are not confused. By doing this another circuit is added, creating another potential undeseriable noise source. Conrad-Johnson equipment is non phase inverting, requiring you to flip plus to minus at your speakers to keep everything in phase. I hope this helps?
Regards,

herman,

thanks for the info, 1 owe you 2 brownie points.

aloha keith

The problem is how many times is the polarity reversed during the entire process starting with the recording?
Most likely a number of times. If that is the case I dont think it makes much difference.

There is an interesting book called "The Wood Effect" (sorry, but I've forgotten the author). This is a rather detailed book that cites many studies and tech papers (with lots of footnotes) regarding 180 degree phase inversion. According to this book, as well as my own observations, by switching phase (reversing BOTH speaker terminal wire connections or using a phase inversion switch, if available, on your preamp), you will get a noticeable change in sound reproduction on most source material! These changes include: wider soundstage, and better soundstage pinpointing of vocals and instruments.