Are your specifically talking about the height channels from the upward firing speakers? How high are your ceilings?

The dolby atoms speakers are not working at the moment so it's just the normal sound for the arc, my ceilings are 2.4 m

Ideally the Arc should be the same level as your ear level, so I don’t think lowering the Arc will improve the sound. Have you tried redoing Trueplay tuning?

I don't have an iPhone so don't believe that's an option with android? 

Do you know someone with an iPhone you can borrow for 10 minutes? You just need to run Trueplay once.

Yes I do,I'll try that tomorrow and see how that goes, thankyou all for now 

I purchased the ARC about 2 months ago and judging by what you wrote I would recommend trying 2 things. First use the TruePlay tuning to optimize your rooms sound- I noticed a significantly better acoustic experience when I did that after setting mine up. 

Second of that doesn't meet your needs I'd def lower the height of your soundboard.  It should be between chest and ear level from a sitting listening position and it sounds like yours is a bit too high right now.  Good luck

One more thing- I see you mentioned you don't  have an iPhone,  I was in a similar situation but you can also use an IPad to run the TruePlay which is what I did. 

Also as mentioned by others if you don't have an iPhone or an IPad if you can borrow someone's iPhone it only needs to be run once so you won't need to run it repeatedly.  Good luck