Anyone good with trigonometry?

banja

banja

banja

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At least I think the problem requires trigonometry.

I need to know what distance to place two speakers away from each other, given that they both need to be 30 degrees from a listening position.

So for example, say I'm sitting 1.5m from the centre point of the two speakers, I need to know from just that detail and the 30 degrees factor, what distance to place the two speakers apart.

The distance won't necessarily always be 1.5m, so I guess I need an equation.

Please help, it's a life and death situation*

*not even vaguely true.
 
You need to to place one speaker to get a second data point then it is easy* trig.

*easy if i were 11 again at school

they are going to be bloody close at 30 degrees.... Desktop speakers??
 
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If you think of it like 2 right angled triangles. You have the angle 30 degrees and the length of the Adjacent length, you need to find the opposite length. Tan of the Angle = Opposite divided by Adjacent. So Opposite = Tan of angle * Adjacent.

So in your example the distance from the centre point for each speaker will be...

Tan30 * 1.5 = 0.86

So the formula you need is...

Tan30 * (Distance from TV) = (Distance of speaker from centre)

And then multiply by 2 to get the distance between speakers.
 
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and i bet in school you said 'how will i ever need to know this stuff in real life'....

so you have basically 2 right angled triangles, the longest non-hypotenuse side is your 1.5m [to the centreline of the speakers] and you want these 2 speakers to be on a line crossing this 1.5m and a line that is 30 degrees off, something like this?

btw this is in mm ;)
ocuktrig.png


edit: damn someone got there first....
 
And thanks to the results provided by SilverTongue, I've also worked out that at 30 degrees the distance will always be 115.4% of the listening position distance. Woop!
 
neodude said:
If you think of it like 2 right angled triangles. You have the angle 30 degrees and the length of the Adjacent length, you need to find the opposite length. Tan of the Angle = Opposite divided by Adjacent. So Opposite = Tan of angle * Adjacent.

So in your example the distance from the centre point for each speaker will be...

Tan30 * 1.5 = 0.86

So the formula you need is...

Tan30 * (Distance from TV) = (Distance of speaker from centre)

And then multiply by 2 to get the distance between speakers.
Click to expand...

This is also excellent. Thank you :)
 
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Long time since I did trig, but these calcs on half triangles seem to be based on a 60 degree listening angle not 30 as they have 30 degrees either side of the perpendicular, or was it supposed to be 30 degrees either side?
 
Metallifux said:
Long time since I did trig, but these calcs on half triangles seem to be based on a 60 degree listening angle not 30 as they have 30 degrees either side of the perpendicular, or was it supposed to be 30 degrees either side?
Click to expand...

the total angle is 60 degrees yes, but its 30 degrees to each speaker, the trig is easier to work with if you think in terms of right angled triangles (still not easy enough for me to do it manual though :p )
 
A prisoner was brought before a police magistrate. He looked around and discovered that his clerk was absent. "Here, officer," he said, "what's this man charged with?"

"Bigotry, your Honor," replied the policeman. "He's got three wives."

The magistrate looked at the officer as though astounded at such ignorance. "Why, officer," he said, "that's not bigotry, that's trigonometry."
 
Ugh? Overcomplication tbh


Draw circle
Divide into six
Pin string to the centre of circle
Make an arc with the string over one of those segments (=60deg), starting from where you want the first speaker.


Incidentally, that sounds like an awful speaker configuration,
try putting them half a metre from any wall and just point them 10deg towards you.
Fiddle repeatedly until you can't really sense the speakers location.
 
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