Speaker Height / Tilt

Generally when you sit above the tweeter axis, assuming it has good dispersion you end up with a large hole in the crossover region (2-3K generally). This doesn't exist if you get a coaxial speaker.

Good example is the M106 once you go above axis:  https://www.stereophile.com/images/914Revelfig5.jpg

HI @twoleftears

You asked:

So there’s a "right side up" for raw tweeter drivers? If the mounting housing was round or square and symmetrical, you could actually position it 4 different ways and create different frequency responses?? Same true of mid-ranges?

Nope. The issue is the phase matching with the midrange or mid-woofer.

Others here, as well as the Stereophile link I shared, show this.

Basically, like @jcred pointed out, there is a hole that develops in the crossover region above the tweeter axis of a traditional T - M or T - M - W design.

Basically, imagine you take an ideal speaker, and start pulling the tweeter towards you. As you do, the distance between the woofer and tweeter changes. This causes the previously ideal relationship between the two drivers to suffer.

Hope that helps,
Erik

If anyone is interested and has access to a PC, you can try out Xsim with these crossover files.

You can literally simulate a speaker, and try changing the distance in the simulator.


https://speakermakersjourney.blogspot.com/2016/05/lm-1-bookshelf-crossover.html