Muffled vocals

The distance between the from wall and side walls need to be greater. The front wall is for base and soundstage, the side walls are for timber and image . You need to find a good recording like Jennifer Warrens Famous Blue Raincoat where her voice is dead center and adjust your speakers front to back till her voice is dead center. Your speakers at 30 from the front and 28 from the sides are to similar, try further apart and adjust the toe in so you can barely see the inner side of the cabinet. The distance between the speakers and your listening position should be 1.2 X the distance of the distance between your tweeters.

The above speaker suggestion is WASP and takes time to fully understand and get correct but if you take the time you will be greatly rewarded. Speaker placement I believe is another component and is as important has your other primary source,dac/server, TT, pre, amp, power, cables.

The front wall is for bass' not base.

Geez mon, I hope we're allowed spelling errors. Lol.
As soon as I read your bit about the similar dimensions side and front, it clicked. Yes, everything I read suggested unequal distances.
I was concentrating so much on the music, and trying to ID and assess the changes that I forgot that point.
It sounds pretty good right now, but not for all genres of music. Rock, female vocal and orchestra are quite good, but Jazz doesn't stage well.
I'll alter the dimensions this week and maybe I can improve it more.
Thanks.

Dave.

And Elizabeth, I've been using some well-recorded Mozart, Pink Floyd, and Linda's 'Heart Like A Wheel' album as a control pieces to try to get the speakers in the perfect place. (perfect ... sure).
I tried to choose artists that I wouldn't get tired of listening to. I love the sound of Linda's voice; never get tired of it. And it stages well, too.
I have the current placement taped, so I'll shift them a little more.

Oh yeah ... also, when said that Elton John's piano is never center stage; I meant when he performs. So, it really shouldn't be centered between the speakers, I wouldn't think. N'est ce pas?