Some CD players let you reverse the polarity of the digital code read by the DAC chip, becauase some CD's are possibly recorded wrong. This is not the same as inverting absolute phase. It is more similar to reversing the AC plug polarity, which is also not the same as inverting absolute phase. I use to own the Rotel RCD-990 that does this. (The RCD-991 does not.) |
Yes, the Meridian manual sais it is a phase adjustment, and just might be different from the polarity adjustment in the Rotel. But I would check with Meridian directly. The terms phase and polarity are interchangeable and could mean the other. Changing the phase in the Meridian may still not be the same as reversing your speaker cables. It may be doing what I described above. |
I emailed someone at Meridian for a definitive answer. I honestly don't what that switch does. I just know that absolute phase is not always what you assume. The Rotel manual clearly stated that their phase switch only affected the polarity of the recording. It did not affect the phase of the overall system. A system that really is out of phase is usually very noticeable, because certain frequencies will cancel out with the sounds created by the resonance of the listening room. Reverse the speaker cables on only one speaker while playing something in mono. Then put the speakers right together (touching) with the grills facing each other. If the phase of each speaker is perfectly out of phase with the other there will be little or no sound. (Perfect cancelation). |
I received a response from David Hall of Meridian Audio. [email protected] The phase switch only changes the phase of the CD player. It does not affect the whole system. Therefore, this is the same as the Rotel I mentioned. I am not Silly after all. This makes sense. Preamps like Conrad Johnson and Blue Circle are out of phase and require you to reverse the speaker wires. Their literature states that they would have to add another gain stage to those preamps to make them phase correct. They don't because it would only degrade the sound. If all they had to do was reverse the wires going to the analog pre-outputs they would; but it evidently is not the same thing. |
Then please educate me and explain why companies make gear out of phase and then tell us in the manual we have to fix the problem by moving the speaker wires? I'd would really like to know. Are all those audio engineers so stupid that they can't just reverse the wires inside the unit if the solution is that simple? This still might be what that Meridian switch does, which is consistant with the Rotel phase switch which to repeat that owners manual again; changed the absolute phase of the recording by 180 degrees, but does not change the phase of the speakers. Why would the Meridiam be different, if this is a feature to add to a CD player that Rotel probably copied? I did own the Rotel BTW. So we have two different people at Meridian giving different answers. One at the manufacturer in the UK, the other at the US Sales office. So the guy in the UK is automatically wrong based on what? I really don't care which answer is right, I only care that we have a right answer. I just know that phase and polarity is a very misunderstood subject and is not just one thing. Paulwp, Do you actually limit your comments on Audiogon to gear that you own? Currious? |
Who knows Paulwp ? I actually gave the Meridian guy in the UK a free choice of "A" (effects only the CD player Digital code only) or "B" (reverses speaker phase), so I hoped there would not be any confusion. He picked "A". You would think working in the UK where they design and make the stuff he would know ?? Oh well !! I did not lead him into one answer. No matter what that Meridian switch does or does not do, the basic concept of what we are discussing does not seem possible to me. We have an audio system that has two completely closed hard-wired electrical paths; one carries positive electrical current, the other one carries negative current. We are being told to believe that music encoded as 1's and 0's on a piece of computer media (the CD) can cause the positive electical current to change into negative electric current (and negative into positive) causing your speaker to physically go in (have suction), instead of go out (pressure). If this were a vinyl LP recorded out-of-phase, then a piece of plastic with rough grooves on it can cause positive electric current in a hard-wired system to change to negative current (and negative to positive). Since we have already established that audio gear would need to have another actual electrical circuit (gain stage in your example) to invert the phase; then when we insert a out-of-phase recording into a CD player (or LP on the turntable); our audio system must be physically growing another circuit or gain stage (which would of course instantly disappear when presented with music recorded in phase). There is no other physical way for the actual electrical current to change polarity. I've seen this watching Star Trek on TV. They put what looks like a computer disc in a slot, and matter instantly forms into their lunch out of thin air. Now Rotel stated in their owners manual that their phase switch only inverts (corrects) the digital code in the DAC chip, and has no effect on the actual electrical phase of the system. Now this sounds logical to me. So the Meridian switch may actually add (or remove) a stage (phase variance) to the path to invert the polarity of the electric, which is fine. But the CD cannot (I assume). The Meridian then plays an out-of-phase recording, out-of-phase. Then two wrongs make a right? I have a client who is a digital design engineer for a company that makes Pro-Audio equipment. Next time I talk to him, I will ask about phase variances in the digital bitstream and see what he says. |
