Question Dali Alteco C1 output angle


Standard Member
Could anyone with a pair of Dali Alteco C1 tell me what angle the drivers are from the floor plane? I believe Atmos standard means 21 degrees but these are not Atmos certified so they were free to do what they wanted I assume. From measuring a side on photo on Dali's site, it seems the grille is at 23 degrees from flat, but the recessed panel housing the drivers is steeper than that. Just assessing the situation before I make some decisions on upfiring Atmos speakers.

Thanks in advance.


Active Member
I have a pair and, a while ago, I did some measurements and trigonometry to figure that out. I've lost it but I could redo it for you later.


Active Member
I made some measurements while brewing coffee.

From the side, ignoring the grille and rubber feet, you can regard it as a rectangle with a triangle on top. The base is 250mm. The height at the front is 80mm and the back is 186. So the triangle has height 106mm. So the tangent of the angle is 106 / 250 = .424 and the angle is 40°. This is a bit more than I would have guessed by eyeballing it so I might remeasure it later. It is also quite different from your 23°.

However, there is a complication which I forgot previously. The speaker is not level with the grille. It is depressed further at the front than the back. It is harder to measure this accurately. Partly because it is just a few milimetres but also because some foam blocks measuring it at the front. At the back, the depression is 8mm. 95mm towards the front, where the foam starts, it is 15mm. So, a similar calculation gives an angle of 7.3°.

So, altogether, the inclination of the speaker is about 47°.
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Active Member
A post coffee remeasurement. I got the slightly neater values of 250, 80, and 185. As a crosscheck, I measured the sloping side and got 273mm. My friend Pythagoras thought it should be 271 but that's close enough for me: within 1%. This gives the angle as 39.7°.

The inside slope is still a challenge without better tools or dismantling the speaker. However, I had an idea of holding a piece of paper in it and marking the paper. This led to the slightly greater angle of 10°. I am not claiming high accuracy here but it's probably closer than my previous value.

So, now, my estimate for the speaker slope is 50°.

I need to remeasure my room and listening position. Previously, I calculated that I was in the optimal position.


Active Member
According to Dali themselves they are angled at 21 degrees.



Active Member
That's weird. My measurements can't be far off and you can check the maths if you like.


Active Member
I found the manual. It says that when the switch is set to up, it delivers the sound perpendicular to the front of the speaker. When set to down, the sound is angled down by 25 degrees. Nothing physically moves, so something else is going on.


Distinguished Member
How did Dali work out that 21 degrees is going to be suitable for all sized rooms and speaker layouts.

Surely they won't be pointing to the MLP is every room.

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