Speaker size and soundstage

Check out Tannoy's. After a year of moving things around and learning more about speaker setup, I finally found the magical position for the Turnberry's. Since then, it's been heaven. Nice wide and tall soundstage and I have depth. Imaging is excellent. 15x20 room with not a whole lot of room treatment. My listening area is open and no clutter near the speakers or in front of the listening position. Gear is also down low and horizontal. It makes a difference. More room treatment and solid doors are next on the to-do list.

I agree with those who have pointed to adding a pair of Subs to increase your Soundstage, for your situation. Getting another brand of speaker in the same price point is more of a lateral move than an investment in achieving your goals.

I have speakers that perform very well within a frequency response between 30/28Hz - 40KHz. That said, after a few years I found myself wanting a more dynamic soundstage without breaking the bank. By adding a pair of REL subwoofers, I was able to extract deeper, cleaner bass,  fleshed out detail in the midrange and greater sense of spatial separation. I would guess that the low frequency is about 20/22Hz.

Good Luck

Lyndonbell. You are asking about “Crossover settings” on your AVR. YouTube had excellent vids on this subject.   This forum is full of nitwits who won’t give a straight answer.    

As to speaker size, large floor standers xylene to have a rich full sound especially for large rooms.  That is my wife’s preference.   But nothing to do with soundstage and imaging.  Personally I think Sonus faber make some of the best.  https://www.sonusfaber.com/en/products/olympica-nova-i/

Tektons have a terrible image. Stay away.

Those who have actually heard them beg to differ:

The imaging was so good that I felt like the vocalist was performing right in front of me and that I could reach out and touch them.   

I enjoyed hearing everything but was most shocked at Fleetwood Macs "Landslide". Hearing it so many times in the past and then not recognizing the intro because of the detailed soundstage. Then Chuck let Stevie Nicks sneak into the room and begin the vocals dead center right in front of me and the recognition set in.   

The soundstage starts a few feet behind the speakers, and extends well out into the room, seemingly surrounding you. I've never (in a true two speaker setup) felt so enveloped by the music as I was last night.

...a near religious experience.

https://systems.audiogon.com/systems/8367

Tektons, at least the ones I have heard image poorly. But so do a lot of speakers. This is political incorrectness at it's best but, most people have never heard a system that images at the level the source is capable of and that includes those that would characterize themselves as audiophiles. They parrot the terminology used in the literature which is frequently stupid like "pace" and "timing" and think that echo is the third dimension. It is not. Some speakers like the Tektons are incapable of the best image by design. But, many are capable if managed correctly. What is correctly? The speakers have to be set up in a symmetrical situation.
All first reflections need to be dampened with sound absorption. The speakers have to be within 1 dB of each other from 100 Hz to 10 kHz.
If they are not all is not lost. You will have to apply digital EQ to make it so. This also allows you to adjust the overall frequency response to produce the sound you like. Doing all of this does not insure you will get the best image. That depends on the speaker's design particularly the crossover. How do you know if you have the best image or not? You have to have heard a system that images at this level. Once you do you will never forget it. If you do not have it now it is all about the speaker and the room. If you are sure you have the room treated correctly then you need to change speakers. I can count the speakers on one hand that I have heard make the magic. Most of the speakers that I have owned did not and only two have really had it.