Line Source - to toe in or not?

@bdp24 

Theonly way to inow what you are hearing is to measure.

Be tweets have, often, a combination of the best and worst traits.  While there are some really crappy AMT tweets, with terribl frequency response I have never seen any of them javesignificant stored energy

There is no cure for the time-domain performance characteristics of a driver;

I’ve seen good evidence that notch filters not only can damp the ringing, but also reduce overall tweeter distortion. Having said this, I’ve never purchased a tweeter with significant ringing, so I can’t argue the point much with first hand information. See if you can find the old threads at DIYaudio on this.

A similar argument is made in rooms, something about linear phase systems can be damped by reducing the input. In any event, I won’t argue this point, but thought it was interesting.

What I can say is that there’s a lot of metal dome speakers out there with measurable ringing in a lot of reviews and living rooms. While personally I prefer to have tweeters with little to no stored energy, lots of people have no problem with them at all.  They may even give the listener a euphonic sense of air. 

@bdp24 Missed the most common and obvious answer for a lot of speakers:

Some drivers simply sound better off-axis. It’s not uncommon for a speaker designer to take a tweeter that is bright, or rings on-axis and tame it by designing the speaker to be listened to "off-axis" or rather, with little to no toe-in. In my mind, the Focal inverted dome’s are famous examples of this.

It is also quite possible that speaker designers realize that speakers look better flat to the wall and voice accordingly. Some combination of these two accounts for most of these situations.