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Old 19th August 2019
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Jens Eklund's Avatar

Originally Posted by Soundman2020 View Post
As soon as you rotate the speakers, or move the mix position, there is no longer an equilateral triangle. Period. End of story.
Originally Posted by Soundman2020 View Post
This is actually very simple: what is the distance between the speakers? What is the distance from each speaker to your ear? If those two are not the same, then you do not have an equilateral triangle.

This isn't about where you put the aim point for the speakers, or anything similar. It's about the speakers, and your ears. That's what matters. That's what the triangle is all about, because at the end of the day what matters is what you are hearing, not how nice the lines look when you draw them on paper, or which way the speakers happen to be pointing: What matters is the acoustic axis of each speaker, and the location of your ears. Measure the distances, and if they are not equal, then you do not have an equilateral triangle. Point the speakers straight back, at each other, toed in, toed out: that's not entirely relevant (although it does matter, of course). What is relevant to having an equilateral triangle, is the way your ears see it, period. As far as I can determine, the justification for the equilateral triangle is that it gets the sound waves arriving at your ears at an angle of 30°, and the ONLY way you an do that is if the distance from each ear to the relevant speaker, is the same as the distance between the speakers. If you angle your speakers at 30° toe-in, but then sit forward of the apex, the distance from each ear to the speaker is LESS than the distance between the speakers: thus, you do not have an equilateral triangle any more. On the other hand, if you toe-in the speakers slightly LESS than 30°, such that the apex is further back in the room, you can then sit inside the apex and actually get an equilateral triangle, with respect to your ears: the distance from ear to speaker can be the same as the distance between speakers, even though the physical toe-in angle is no longer 30°, the angle from ear to speaker is 30°.

That's the issue that folks seem to be avoiding here, or not wanting to see: what matters is your ears and the speakers: If you want an equilateral triangle, then that's where it should be.

Boggy has been saying this for years. So have many others: Use whatever physical toe-in angle you need to get the listening position where it needs to be. There's no need to follow the old-school rigid, strict but unjustified "rule" of using exactly 30° and placing your head exactly at the apex. That's the way things were done 40 years ago, before the science of psycho-acoustics, and the research, and the lab testing, showed how our hearing actually works, as opposed to how it was thought to work back then, when the "triangle" first originated. Science moves on, and there's no need to stick to the myths of the past.

To throw another item out: it turns out that 30° isn't even the bet angle for hearing anyway! If you look at the polar pattern for ear sensitivity, our hearing is most sensitive somewhere around 40° to 50° off the median plane (it varies by person, and by frequency). So maybe an angle of 45° would not be too bad either!

- Stuart -

So ...

Are you now accepting the fact that you can "rotate" (toe in/out) speakers and still manage an equilateral setup?