Tech question. What is the proper term for this and why does it happen?

Listening to my early, dual fused, Monitor 10s. Comparing them to a set of "other" vintage speakers.

The Monitors have the sound stage focused. Voices in the middle are IN the middle.
I can move left and right a few feet, in my chair, and the voices remain in the middle.

The "other speakers" have the voices shift left-right under same conditions!
And not synchronized: Left movement can shift soundstage left, or right!
And vice-versa...
Basically, I have to remain STILL for the "other speakers" to center the voices.

Ok, what's the technical term for this and what is lacking in the other speakers that the Monitors are getting right?

Thanks for any insight...

Comments

  • jdjohn
    jdjohn Posts: 3,162
    Sounds like the other speakers have a very small sweet spot, whereas the Monitor 10 have better dispersion and wider projection. This is probably, in part, due to the soft dome tweeter that Polk used. I'd better the other speakers have a small cone tweeter.
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  • Emlyn
    Emlyn Posts: 4,531
    It's also possible to make the "sweet spot" from a pair of conventional speakers bigger or smaller by the changing the amount of distance between them, changing the distance from the center point between the speakers to the listening position, and the altering the degree to which the speakers are angled inwards to the listening area.

    Question: which pair of speakers sounds better when sitting in the sweet spot?
  • odcics2
    odcics2 Posts: 339
    Other speakers compared were KLH Model 6 and OHM L.
    Both have paper tweeters.
    I played around with angles and stands, both flat and slightly angled up.
    You CAN get the others to a correctly image, but then your head is locked in a vise! An inch or so either way from the sweet spot and the sound stage shifts.
    And, its not just the treble, but midrange too.
  • odcics2
    odcics2 Posts: 339
    So, I moved the KLH speakers a bit closer together, put them on my Polkstands, with the metal tops, angled in a bit and they sounded much better!

    Sold off the OH Model L speakers, so I can't see if they'd improve being a bit closer together.

    I'm thinking the side walls were reflecting sound. One wall has nothing by it, the other has a 3 foot high shelving unit filled with albums and other stuff. A hard room to get things perfect, IMO.