audio update

So I got fed up by both my smartphone's audio quality and my headphones and decided I need a decent player

I got a Cowon iAUDIO 9 and Koss Porta Pro headphones. Really, I wanted to get iAUDIO 10, but there was none in the shopping centre and I wanted to get it today and enjoy the music ASAP.
http://www.cowonglobal.com/product_wide/iAUDIO9/product_page_1.php

As for the headphones, I find Porta Pro quite nice. For $30 they're the best. Their frequency response shows no ringing in the high frequency range and they have very powerful low frequencies (which some people find rather a disadvantage). The drawback is that for such clear sound the price is the 60Ohm impedance making them sound quiet on most players. I was having AKG K430 for some months and find them not so pleasant to use. There are almost no low frequencies and the sound in high frequency range is a bit distorted. Besides, Porta Pros look cool and stylish. But they're made of a very weak plastic and break easily. If it were not for their low price, I would never buy them or recommend to anyone, but as you see, I've fallen for them for the second time.

Some minor problems I've found:

1. USB access is slow. no, it's SLOW. took the whole hour to copy the 9GB of music
2. Player menu is a bit slow. The screen lags behind the actual input handling. If you click "play" and then scroll through the playlist, it will actually rewind the music track
3. Not a problem, but a counterintuitive feature. Rewinding at the start of track does not switch to the start of the previous track, but rewinds to some last seconds of it.

The good points however are:

1. Output power and SNR are above average (30mW and 95dB for reference). Enough to driver even the 60Ohm Porta Pros.
2. Easy to use menu controlled with two keys and the scrolling area
3. Supports directory browsing (as opposed to album/library browsing which is the only available option on most players today)
4. Easy to control the volume and tracks with hardware keys while it is in the pocket
5. supports FLAC

Overall, I'm very happy and find the sound quality good - it is loud and frequency response is more or less flat, so the sounds of all frequency range are audible, there's no lack of bass and the sound is detailed because high frequencies are not exceedingly powerful and middle ones are not silenced like it often happens.

So, why was I dissatisfied with my Galaxy S2?

1. output power is low and frequency response is far from flat. This means sound is too quiet in the headphones and one needs to tweak the equalizer to make low frequencies ("bass") audible and high frequencies not such irritating
2. it is running Android. I dunno why, but after I've installed a couple softwares (including Twitter and  Foursquare) and enabled GMail synchronization, my phone is periodically becoming extremely slow. So sometimes even the music playback is quirky
3. it is running Android. when I copy the music via USB using it in Mass Storage mode (USB Flash Disk emulation mode), I need to reboot the phone a couple times or force the media refresh via the developer menu to make the player see the files
4. it has a dual-core CPU. and a huge screen. and yes, it is running Android. When you enable 3G, it does not even last the whole day. And takes too much space. Switching tracks on the go is inconvenient.

What I did not like about my previous phone (Sony Ericsson Xperia X1)?

1. Output power is too low to drive Porta Pros
2. Quirky sound. Actually, the problem is that the sound system of the phone uses multiple buffering and a complex synchronization scheme for them. The fact is that there are two processors, the ARM11 core running Windows Mobile (or linux/Android thanks to our work at htc-linux.org) and the ARM9 running an L4 kernel which manages some peripherals including audio. Audio is controlled via RPC. Sometimes, and unfortunately too often for me to ignore, a buffer underrun happens. That is, when the audio system is expecting N samples in the queue, but only M are available, and M is less than N. When that happens, you hear a clicking noise or some random stuff that was left in the buffer before. Unfortunately on most devices having MSM7200A CPU this issue occurs approximately once in some 10-15 minutes making sound awful.