Center speaker angle?

[kinggimp82]

My room does not allow for many options to place my center speaker (Sierra-1). The only place that works is above my TV on a mount. The bottom of the speaker is 65 inches off of the floor. The way my seating is set up people are sitting between 7 and 10 feet away from the center speaker with the average ear height of roughly 43 inches. Don't know if it matters but my main speakers (Sierra-1s) sit on 34 inch stands. I am going to put something underneath the back of the speaker to angle it down towards the listing position. How much should I lift the back of the speaker in order to get a proper angle down towards the listing position? I thought probably around 2 inches of lift would work. Any thoughts would be appreciated.

[curtis]

It should be pretty easy to eyeball and see that the speaker is pointed toward the seating position.

[Dread Pirate Robert]

My room does not allow for many options to place my center speaker (Sierra-1). The only place that works is above my TV on a mount. The bottom of the speaker is 65 inches off of the floor. The way my seating is set up people are sitting between 7 and 10 feet away from the center speaker with the average ear height of roughly 43 inches. Don't know if it matters but my main speakers (Sierra-1s) sit on 34 inch stands. I am going to put something underneath the back of the speaker to angle it down towards the listing position. How much should I lift the back of the speaker in order to get a proper angle down towards the listing position?

The formula for calculating the rear lift height (all units in inches) is:

sin(arctan((65 + 7.5/2 - 43) / distance)) * 10.5

Which simplifies to:

sin(arctan(25.75 / distance)) * 10.5

So at a distance of 7 feet the lift should be about 3 1/16 inches, and for 10 feet it should be about 2 3/16 inches. Splitting the difference in terms of angles requires 2 5/8 inches of lift.

And don't forget to secure the center speaker.

I thought probably around 2 inches of lift would work. Any thoughts would be appreciated.

That's a good guess.

It should be pretty easy to eyeball and see that the speaker is pointed toward the seating position.

...yeah, that could work, too, sort of like using pencils in space.

[Jonnyozero3]

That's some serious math throw-down for us history majors.

How does the equation change for placement below a screen?

[Dread Pirate Robert]

That's some serious math throw-down for us history majors.

It's high school math, as I remember, and it's still just an estimate because actually moving the speaker very slightly changes the parameters, which are estimates to begin with.

But really, eyeballing it should be close enough, and it's exactly what I did for my own system. I just thought it would be nerdy-fun to actually work out a basic formula to find a fairly precise theoretical answer.

How does the equation change for placement below a screen?

The part that you take the arctan of is just the difference between the vertical heights of the tweeter and the viewers' ears, divided by the distance--figure that out any way you wish, run it through the formula, and then apply the result to the lift height on the front of the speaker instead of the rear. The 10.5 factor is the depth of the speaker in inches, so you can change that, too, if needed.