Speaker Set-Up: Use of a Plumb Bob

Kinda curious if it is important to ensure that speakers are vertically positioned by using a plumb-bob or similar tool (e.g., bubble-level). If so, aside from avoiding listener dizziness or eye strain (LOL), ... why? Does it affect performance in some way??

Thanks and Happy New Year.

I have mine gimbal mounted with built in gyro's.
It's important that both loudspeakers are the same, but whether that's straight up or titled forward/back depends upon the design, your room and your listening chair height. Most loudspeakers give their smoothest response only within a small range of the vertical axis. Look at the graphs in a Stereophile review to see examples. You usually want to tilt your loudspeakers so that you're within that range. The sonic effect can be very noticeable.
Thanks Onhwy61. I tilt my speakers slightly forward to reduce the vertical off-axis angle. However, I'm kinda curious about the speakers vertical configuration. My basement floor is not even. So, when checked with a bubble level, the left speak is pretty close to being 90 degrees true. By contrast, the right speaker required me to shim up one side in order to be true.

I guess the question is whether this is another issue to obsess about.
"I tilt my speakers slightly forward to reduce the vertical off-axis angle."

What are the before and after measurements of the vert off axis angle?
If you do as you have, the difference is probably infinately small & even un noticable. Less than if you have one in an awkward spot in a room, meaning the area has an open door close by or an L shape or a bunch of other things. Get them as close as possible to the ideal. Rugs & funiture should also be considered.
Zd542, I unscrewed the rear spikes to lift the back of the speakers, thus tilting them forward and pointing the tweeters more directly on axis towards my ears when I sit in my listening chair. I can only tilt the speakers forward by so much because their center of gravity is high and close to the speaker fronts. I am concerned that too much forward tilt could increase the risk that the speakers might fall over. This adjustment is not the subject of my question.

Rather, looking straight at the speakers face-on from my listening chair, I can see that the speakers lean sideways because the slab floor isn't level. I tried the best I could to straighten the left/right tilt with shims and by adjusting the spikes. My question is how critical is this adjustment. I think Vandy owners spend a lot of time with this adjustment. I was wondering just how critical it really is.

Maggies look better if they are vertical..
I'll try the plumb bob. Most of the time I just use a tape measure to properly situate my speakers.
Hello, Onhwy61 gives true advice, the closer they are to exactly imitating each other, the more exact everything is going to sound. I believe that after all else is said and done, many people neglect the last ounce of attention to detail with regard to exact speaker adjustments. yes, fore/aft & L/R are obviously key factors but getting the rake angle can also be very influential with most speakers and absolutely critical with others.Generally speaking, cone speakers are probably more forgiving but this angle can be the final factor when it comes to locking in imaging and improving location and placement of performers and their spatial characteristics.
Planar speakers are often much more dependent on rake angle being even and precise as it will truly snap the final focus into place. My planars are exactly rake adjusted [with plumb bob] to within 1/16th" as are the toe in measurements too.When they are out of adjustment I can tell...but [while keeping them basically level for the other placement adjustments],save rake as the last adjustment you make and you'll see ("hear') what I mean. Yes,it's worth the extra effort. Good luck.
I did not use a Plumb- Bob to set up my speakers, but my friend Billy Bob helped.
I often read about people with much more experienced ears than my own making 1/16th or 1/8th inch adjustments to their speaker positions until "everything snaps into focus."

If that's the case, then wouldn't one have to have his head in exactly the same position, in all planes, to keep everything in focus? To move one ear 1/8th inch closer to the speaker and the other 1/8th inch further away only requires an almost imperceptible turn of the head.

I am not a skilled listener, so I'm not saying that people who do hear the difference are wrong, I'm just wondering if I should spend the time making many, many very small adjustments to my speakers. My head position when I listen can vary several inches in different directions due to a variety of factors.

So let me just ask, who has experienced the one exact right position for speakers and who has tried but did not find it. No one is right or wrong, just what was your own experience?
I use a bubble level to set up speakers. I want speaker stands perfect vertical to the floor. Drivers of each speaker must be same distance from a listening chair. I hear and see perfect images and wide soundstage.

Music recordings are not perfectly recorded. Speakers and rooms in recording studios are not perfectly accurate. Also, recording engineers don’t have perfect ears. Centers of recordings are not dead centered. I’ve just checked few songs. Eva Cassidy “Time after time”- center is 6” to right. Eva C. “Over the rainbow”- 6” to left. Jacintha –“Danny Boy” – 6” left. Jacintha “Light my fire” – perfect center!