@ Little-Jonny Hahah, that may just mean you're a bit deaf in one ear !!
Ok, here's my take on this, as a technician. I believe that yes the new cirrus audio chip has different qualities and characteristics to the previous phones.
It doesn't mean it is inferior or substandard. I have proved on my device as I said in a previous post, just by disabling EQ and any other setting in in the music settings in The IOS main settings, will
Greatly boost the volume and clarity.
The reason is the EQ presets in IOS were designed to work only on the older sound chips,
So when setting any preset like, rock, dance whatever completely messes up the dynamic range.
A whole update to the presets needs to be done so they work on this new sound chip.
It's like in the old days of HiFi separates we had a separate graphic equaliser, plugging graphic equaliser into another make of amplifier would make your music sound like pig swill, so you would have to set up the equaliser again.
Why do Singapore IP5's sound ok? Well they are probably made at a different factory where they maybe using the older original sound chip on the PCB, who knows.
So instead of using the current method of using ITunes to mess around with your files by boosting the volume,
Please have a go at making sure you turn the following OFF
EQ setting is OFF,
also sound check OFF
Volume limit is OFF, and volume slider in the limit setting is right up.
It would be interesting to see how many that works for, it works great for me and friends IP5 low volume without all the messing around with ITunes.
If this works for you guys then Apple need to sort out the EQ presets in IOS 6 or sort it when 7 comes out.