Hiho… 
I’m trying to master some tracks for an Ipad game and I’m wondering whether the majority of gamers will hear it through the Ipad speakers vs. headphones. Do you think I should assume 50%/50%? Or 90% listening to Ipad speakers? 90% with headphones? Or maybe it depends on the type of game (platformer)? Any idea? 
Generally every kind of music should sound good though any kind of speaker. lol
I would suggest you take the speaker you know best at first.
Then wander through the room. Maybe there is something you did not noticed before.
Then listen to it at very low volume. What are the prime sounds, which ones are
background only… I take the build in “imac speaker” for that kitchen radio sound
without “feelable” bass and harsh highs and so on. The speakers in my car ect.
But thats “mixing” for me.
Are you the only one involved in the soundtrack?
Greetings
Yes, I am.
Probably, the “Ipad speakers question” would be only solvable if it had no headphones jack at all, or no speakers at all. I was so keen on a simplification. :I
I’ll probably buy a new pair of speakers. Had 8" Behringers with ribbon tweeters for a long time now, sold them, now I want 5" again, A5X. But the Genelec 8020 look so much more stable and handy.
I’d go for the A5X if I had the choice. 
I have such “bassless” monitors (alesis) but would like to have a better resolution in
this frequency range than I have with my hifi boxes. Have you listened to the Yamaha
HS line monitors? The HS 8 are the reference in many studios I know. I like them. They
would fit in my studio well. They even have a 5’’ version (HS 5) which would be worth
to compare with the A5X.
Greetings
I haven’t yet listened to the Yamaha HS. I’ve looked at them on thomann.de and I’m now quite sure I want the 8020 or 8010. I love the round aluminium and plastic finishs more than the edgy wood of the Adams. The Yamaha HS-8 are probably too big, and the HS-5 probably bright and a bit ugly. The weird thing is, doing the composing and the mixing, I can’t decide for either fun vs. analytical sound. It’s kind of unimportant how they sound. 
“Muddy” or “cheap” is probably the only thing they should not sound.
Do you have the alesis M1 Active MK2?
My guess would be that 80% don’t listen at all, 15% use internal speaker on very low volume and 5% use headphones. Haven’t seen any numbers and I doubt there are. Just a guess.
Anyway, I’d recommend trying to mix for the builtin speakers, but not by boosting frequencies that are almost inaudible, but lowering the ones that sound too harsh. If you do it other way around it will sound like crappy bass hell on everything else except the builtin speaker.
No I have the 320. Bought them because they are small and transportable.
I compared them in a warehouse (hamburg) and picked them among others.
They even have a stereo interface which I use for recording my Korg ER-1.
I measured the sound with a noise sweep and they are “professional” linear.
But something around 80Hz they fall steep. Thats okay for being a reference
monitor but I am doing electronic music - the bass is very important.
Have you listened to this ones? KRK RP6 RoKit G3?
They do look good, are small and can play frequencies down to 38Hz.
My favourite right now.
Greetings
Stear away from KRKs… they are like “the Cervin Vega of nearfield monitoring”. -Cheap and loud, but not very accurate. I’ve had the Alesis M1 Active Mk2 for over ten years now. Last year I decided to upgrade after reading countless reviews of Equator D5, where everyone praised them. I didn’t have a chance to demo them, so I took a leap of faith. My best studio-purchase yet! Do some research on the Equators before buying anything else, or you’ll regret it bigtime once you realize you’ve made a big mistake!
Start HERE!
Also read up on the old entrylevel monitors-thread: What Entry Level Monitors To Get??
Depends on what I’m doing. When I play games on a tablet (I have an iPad and a Nexus 7.2), I almost never use headphones, unless it is a rhythm game. I mostly only use headphones with a mobile device when I listen to music or fiddle around with a mobile mini-DAW (like the very excellent Caustic 3). (I don’t like earbuds, and proper headphones just aren’t very mobile, plus most earbuds are hardly better than built-in speakers – the Nexus 7’s ones are actually pretty decent.)
In your case, I’d guess that the majority of people will hear the sound through the built-in speakers. For a wider, more target audience’s response, you could ask over at the Touch Arcade forums, though.