It does work!
Just download it for my LG G2 and it does increase the sounds volume. I didn't want to root the phone or anything as I only brought it this week and to void the warranty on the first week would just be awful!
Without the app, the sound is still very detailed and smooth sounding, but what it does lack is the power and scale of the iPad driver for example. For me, the iPad driver is the best, but the LG G2 is still very detailed. With this app, you get that touch of more power which means increased bass. There is a decrease in sound clarity when this app is in use, but this is not major and doesn't reach uncomfortable distortion levels.
Overall a great app which is free for the first 7 days but then payment is required. But confusingly, it says on the app store that the app costs £1.19 but you actually go on the app and click 'buy complete version' it gives you a link to the Play Store to buy this fish app that costs £2.59. Confusing?
But well done for finding this app for the people who don't want to void their warranty! Much appreciated!
I tried around 10-20 apps this week to increase the volume but every single one did absolutely nothing, like LG had blocked anyone from changing the volumes :S