That's not right - but what's wrong?

I'll try and make this short. Mostly new system of PrimaLuna Prologue Classic integrated amp and Totem Arro speakers with (guessing) between 100 and 200 hours (maybe more) on both. Wavelength Proton DAC or Rotel RCD-02 CD player are used for source. Speakers are wired diagonally with KimberKable 8PR per Totem suggestion, mounted on studs/washers on HW floor. Interconnects are Kimber Kable PBJ, or Audioquest Sidewinder. I also split the output to a different lower quality amp to power speakers in the kitchen. Same interconnects.

Here is the issue; sometimes I get a small distortion of an instrument or voice, although voice is more common, which seems to occur at only one frequency range. It seems most apparent at the start of some vocals. One example is Norah Jones' "Come Away With Me" - almost every pronunciation of the "W" sound starts out sounding like this but then perfect. A couple CDs sound muddled, or undefined which after listening to other CDs has me convinced is bad recording/engineering. Other music sounds great.

I guess my questions are these:
How do I figure out where the problem is so I can address it?
If this is a speaker issue will it go away with time as more hours are on the speakers or is probably something with the speaker drivers (that would seem odd as it's both speakers).
Do you think these are probably more recording errors that I didn't notice on lesser equipment I replaced (Creek 4330 amp/JM Lab Micron Carat speakers)

Thanks for your help.
I do not understand "speakers are wired diagonally"?

Anyway, aside from that:
Most likely an issue with the 'Y' to the second amp.
I would see if the issue disappears if you take out the second amp in the other area to see if the problem stops.

It may be an issue with the wiring to that amp, those wires picking up RFI EMI, or the interaction of the two amps...
Here's what I recommend you try first. Make note of exactly where this happens on a CD. Then take the CD and listen to it in another system. Your problem could lie in the disc itself. I thought my tweeters were broken once because it sounded like they were distorting. It turned out to be the CD. The same thing happened on every system I tried with that recording.
One quick and easy thing to check is tightening all of the bolts holding the speaker units in the speaker cabinet. Even if it does not solve your problem, the bolts work loose over time and should be checked every year or two and may have loosened during shipping.
"speakers are wired diagonally"? What does that mean? Easiest way to diagnose the prob is to do what Elizabeth said; remove amp # 2 from the system. Maybe it is an impedance issue.
Thanks all.
Elizabeth, the diagonal wiring is this: there are (+) and (-) spades for the tweeter and the woofer. Instead of wiring to the tweeter or the woofer and using the binding clamps to transfer to the other, the speaker wires are connected to the (+) on one driver and the (-) on the other. For more info see "Single wiring" here

Zd542 - thanks I'll try that. Unfortunately my headphones need repair so I can't just try direct from the DAC. I still have my Creek but need to solder in some new tweeters on the Micron Carats, then I can try on my previous rig at home. However, I would rather hear it on something that I know is better. One friend has offered for me to send him the time in the track and he'll listen with his reference cans.

Jperry - they're pretty new but that's worth a look and a good maintenance tip all the same. Thanks.
Oh - forgot to mention, the amps are pretty far apart, the new one is on the floor, the other is a couple feet above. The wires do run near each other though as the sources are between or above (DAC) the top amp. Perhaps twisting them around each other would be good?
Jetson, I've read about people using that diagonal wiring approach. I still think it's a possible impedance or gain mismatch between the 2 amps and preamp. Try only using one amp and let us know.