Why are the vocals on some records hidden behind the music on my system?


Help! I am new to this forum, but have been into audio for over 45 years and have never had this problem before. I was lucky enough to come into some money and decided to use some of it to up grade my system for the first time in almost 30 yrs. The system consists of McIntosh MC-402, McIntosh C-100, McIntosh MCD-500, VPI HW19 MKIII, Soundsmith Aida, Furutech Ag-12 phono cable, Furutech silver head shell wires, Furutech interconnects and Furutech speaker cables (yes I like Furutech) and Raidho XT-3 speakers. Now on some albums the vocals are buried behind the music and you have a really hard time hearing the singer? Not all albums are voiced in this manner but enough that it is bothersome. I have a large dedicated man room (24 x 27) with minimum treatment. CDs sound just fine so I feel that it is with the phono preamp in the C-100? I have moved the speakers 100s of times and have them at 5' 8" apart and 8' 1" to the focal point and the soundstage is good and the vocals are better, but you still have to really listen hard to hear certain vocals on some albums. Most of my albums are 30 to 50 years old and have been cleaned with a sonic cleaner (best thing ever imho). Even some of my new heavy vinyl has this problem.
scooby2do
Your speakers too can  clash with your amp,preamp 
the McIntosh are decent but a Pass Labs 250.8 would destroy it 
as well as Ampzilla ,and ambrosia Amp,preamp  little kniwn gems 
from late great Jim Borgiano. Nelson Pass New 250.8 
and many others are far more refined.
i sold Macintosh  nice Looking and dependable, but not the last word in resolution.  For Cd McIntosh for not their Forte.
look up the Lascala, Tube dac, or a Great Lampizator dac ,
or manygreat players .  Rule of thumb don’t buy everything  from 
one company  ,no one makes great everything 
 unless you have $$. Gryphon  .comes to mind , Goldman,
 great Swiss company not too expensive Ensemble.
  Even cables are system dependent . Your system is good 
just a few things  can be bettered for similar  money’s that we’re spent.  Just speaking the truth .having owned a store .

audioman- being in a HI-FI deprived area (rural Okla.) I would have to gone to Dallas, Houston, Denver you get the picture, just to check out any HI-FI stores (unless you count BestBuy). So I bought something that I had heard in the past that sounded good. Now I did go to RMAF in 2017 to hear the Raidho speakers (XT-2 and D-1.2). Wish it was like the 70's with a audio store on every other corner (I lived in Tulsa most of my life). Maybe one of these days I can change it up a bit? Plus all these are used so I didn't pay full price even though it still was a lot of money for me.
I'm not surprised that you found adjusting VTA made a noticeable difference that brought you closer to your goal. IME, it's a super important adjustment; possibly the most important. Personally, I will only use tonearms with VTA adjustment on-the-fly capability. I tweak it for every LP I play with superb results.

That said, I still feel a cartridge that's a closer match to the preamp phono sections would be the way to go.  At a $2K potential budget for a phono stage, you can get a truly outstanding cart that matches either the MC or MM gain on the C100 (a high end rig by any measure).  Without another box between you and the music, BTW.

Even better would be a second hand Graham or Micro Seiki arm with VTA OTF and any one of a dozen <$1K LOMC or high end MM cartridges to mount on it at the same $2K overall.  That approach kills 2 birds with 2 stones (so to speak), and gives you a more flexible platform for the future. I also live in the sticks, and that is a key consideration for me.

Good luck with whatever you decide. Keep us posted and happy listening!

Really, just talk to Peter. He is an audiophile, he uses VPI tables, that's his cartridge - he should know how to proceed further. Might save you a lot of time and effort. 
I think, VTA and anti-skate should always be set by ear with setting VTA first. Take your worst sounding record with vocal and see if you can improve it. I also set VTF by ear, within factory specifications, I know where low and high points are on my arm with my cartridge. Funny activity is to find a compromise. 
Oh yeah, forgot to mention this. Clean a few records again, see if it makes a difference. Just in case.