COWON O2 PMP review

Overall Score

You may be asking yourself “what the heck is a COWON?”  I was indeed asked this very question twice within my first three days of owning the player.  In short, COWON is a Korean electronics company that specializes in portable media players (PMPs) with very broad format support.  Consequently, the brand garners much of its user base among audiophiles.  Here are a couple of quick links that can answer any other immediate questions you may have about the company:

COWON – About Us

COWON @ Wikipedia

The purpose of this article is to explore the features of this relatively new PMP (released in October 2008) and point out its strengths and weaknesses.  Since I don’t own any products that directly compete with this one, it unfortunately is not possible for me to write a comparative review.  However, I have researched the iPod and Zune products extensively prior to buying the O2, so I will sometimes mention features and specifications of those products for the reader’s convenience.  In addition to sharing what I feel are the pros and cons of this player, I will also provide many supplemental images as I discuss in detail the use of the player and its included software.

Although this isn’t a directly comparative review, obviously I have used other electronic devices, and my experience with those devices will undoubtedly affect my perception of this one.  For this reason, I feel that it is worthwhile to mention these products by name so that the reader has an understanding of my viewpoint.  For starters, my primary MP3 player for the past two and a half years has been a SanDisk Sansa 8GB flash player with a 2GB µSD expansion.  Before that I owned an iRiver IFP-899 1GB, and before that I had a number of Sony G-Protection portable CD players.  Just a couple months ago I purchased a Microsoft Zune 120GB to replace my Sansa but returned it after only three days because I was dissatisfied with its performance, particularly its tendency to skip while playing lossless audio.  Lastly, I have used a 5th generation iPod Classic 60GB for several hours and am familiar with the interface and capacitance wheel control.


As I mentioned earlier, COWON is a popular brand among audiophiles due to support of a large number of formats, particularly lossless audio formats.  This is one area in which major brands in the PMP market have fallen short.  For example, both the Zune and iPod lines of players claim to support lossless music; for the Zune that means WMA Lossless, and for the iPod it is AAC Lossless.  Unfortunately those claims are not delivered upon, as both product lines have their share of problems, which we will discuss in just a moment.  Other popular brands like Creative and SanDisk do not claim lossless support on their players other than the raw, uncompressed WAV format.  Indeed, I have tested WMA Lossless on the Sansa e280 and Sansa View, and both players report the files as unsupported.

With the 2nd generation Zune players (but not the 1st generation models with the wheel control) there seems to be an inability to handle high bitrates, resulting in skipping and delayed playback.  If you ignore the vague marketing claims and read the actual product manual in detail, you will find that it specifies support for up to 940kb/s.  However, many lossless encodings exceed this rate and therefore cannot be decoded quickly enough by the player.  My own experience with the Zune120 is documented in this thread: Xtreme CPU Forums — 10/13/2008 — Zune Help!.

The entire current iPod line suffers from similar problems.  A quick Google search reveals numerous customer complaints about lossless files skipping during playback.  For example, one user at iLounge Forums described an issue with the iPod Nano fumbling when switching tracks, while another user on the Apple Support Forum stated just last month that the newest firmware revision for the iPod Touch still does not address the lossless skipping problem.

Lastly there is the issue of sound quality.  After all, what is the point of using lossless audio if the player doesn’t have a clean output?  The iPod is frequently called out in reviews of the Zune and other competing products as having inferior sound quality, a largely subjective claim which I have not yet seen quantified with frequency response plots, save for one site which published a hoax back when the original Zune launched.  However, many users now agree that Apple has taken a step backward with the newest iPod Classic players when they switched to a cheaper DSP (digital signal processor) chipset.  Most of the online chatter about this topic stems from one source, a blog posting in which an audio engineer analyzed the frequency responses of the 5th and 6th generation iPod Classic players.

Before this starts sounding too much like a commercial, I want to mention that there are PMPs on the market from brands other than COWON which support lossless audio.  iRiver, for example, has long supported OGG and FLAC on their players, and Archos is also known for broad format support and great sound quality.  Even the first generation Zune, if you can find a used one for sale, will work perfectly with WMA Lossless.

Okay, okay, enough about other players – this is a COWON review, after all, not a Zune or iPod or whatever else review.  I merely wanted to point out the reasons why the O2 is such an appealing choice for high quality audio, and to hopefully save you from some of the disappointment I experienced with players before I bought an O2.  With that objective achieved, let’s move on to the good stuff.

According to the heading here, I was going to use this section to tell you who needs an O2.  We already talked about audiophiles, so who else cares?  Well, lets first look at who doesn’t need an O2.

If you buy your music from online sources which use DRM, then you don’t need an O2, because it doesn’t support DRM-protected formats.  If you are an avid iTunes user, just stick with the iPod, because it’s perfectly suited to your needs.  In fact, if you use iTunes to manage your music then you will quickly find out, if you haven’t already, that it only syncs with iPods anyway.

If you want a slim and sexy player to toss in your pocket or perhaps carry while exercising, then you don’t need an O2.  This player is huge compared to an iPod Touch and it’s also bigger than a full-size Zune.  A compact yet versatile player like the iPod Nano or Sansa Fuze would be much more practical in your case.

If you want a player with tons of random features, then you don’t need an O2.  This player doesn’t have a phone, a GPS receiver, or WIFI connectivity.  It’s not a PDA and it doesn’t have games (though it does have a sketch pad and a calculator, and an SDK has been released, so other applications may show up in the future).  The O2 has one thing that it does really, really well – it plays your media files (audio, video, and pictures).

Now that we’ve eliminated a sizable portion of customers in the PMP market, let’s talk briefly about those who remain.  If you want a player that is simple and intuitive to use, supports many file formats without having to transcode, has great sound quality, has expandable storage space, can output video to a TV, and follows industry standards for PC interfacing, then the O2 is very well suited to your needs.

Here’s what $260 will buy you:




In all its glory…


The power supply is unique in that it comes with clip-on adapters for both American (Type A) and European/Korean (Type C) electrical outlets.  I realize that this may seem odd since these regions use different voltages, and for this reason I have included an extra image of the specifications printed on the supply.



iAudio earbuds:


A standard mini USB cable:


The stylus bears an unexpected rectangular shape and has a rubber pad built in on one side.  This is because the stylus opens up to serve as a simple holding stand for the player.  I didn’t like the stylus much though, so instead I use one that I had left over from an old PDA.





Lastly, we have the manual, mini-CD of jetAudio software, and various other documentation (much of which is not in English).



All of you freelancers out there will likely smile at this next image.  It is common knowledge that directions are overrated.  In this case, you can safely discard all of the literature, as it contains nothing of importance, only things that you can easily figure out on your own.


For a limited time, JetMall is offering a plastic screen cover free of charge.  Normally this would cost you an extra $15.



Since this player was purchased for my personal use and not just for review, I also opted for a couple of accessories.  The first item is a polycarbonate case for the player, which cost me $15, but is now included for free as part of a current sale.  This case does not provide any sort of screen protection, so you will still want the sticky plastic cover in addition.




The second accessory that I purchased was a TV output cable, for $9.  This cable attaches to the mini USB port on the player and provides RCA connections for 2-channel audio and composite video.





Not much to see on the reverse side of the player, just a speaker and some printed specifications.


On the right end of the player are the microphone and combinational power/hold switch.


On the top side are the volume switch and battery indicator.  The indicator is lit green when the player is in use.  When charging the battery it instead lights red and turns off when charging is complete.


On the left side are the headphone jack, power jack, and port cover.


With the cover open, you can see the combinational USB and TV out port, SD slot, and hard-reset button (which I have yet to use).


This is the flash card which I used to test the player.  It’s a Kingston 8GB SDHC card, which requires the pictured adapter for use in a full-size SD slot.


The card gets installed like so (shown inserted halfway here):


The instructions for installing the screen cover were extraordinarily unhelpful…



On the outside the O2 resembles an Apple product, or at least that is the case for the white version of the player.  Don’t let this fool you though, as the imitation stops there.  This is neither an iPod killer nor an iPod clone; it’s in a completely separate league.  One look at the UI tells you that the design team had a good balance of engineers and artists, because while the interface is simple, straightforward, and functional, the graphics are also clean, tasteful, and even slightly shiny.  As a firm believer that ‘less is more’ I am definitely pleased with the color scheme, layout, and ease of use of the O2’s interface. 

So what about the player itself?  Well, it’s definitely not slim and sexy like an iPod Touch.  With dimensions of 4.70” x 2.89” x 0.70” the O2 is a bit larger than the iPod, over twice as thick, and at 7.2 ounces it also weighs 78% more.  The larger size comes as part of a trade-off for features, as the O2 sports a huge 4.3” screen, compared with the Touch’s 3.2” screen.  Still, it should be noted that the iPod’s screen is actually higher resolution — the finer pixel pitch yields a potentially more detailed image.  Due to the target market for this device, I do not personally consider the size or weight to be cons, rather I consider them both expected and reasonable.

Overall the O2 seems to be very well made, despite being encased entirely in plastic.  The back does flex a bit if you press on it, but it still does not feel flimsy.  Even the cover over the USB port and expansion slot feels durable, as it is made of a hard but flexible plastic and is attached by rubber hinges.  While I wouldn’t recommend dropping the player routinely, I also would not worry about tossing it into a backpack for transport.  The only part that I would consider fragile is the screen, but that is the case for almost any player.  If you are still worried about the player’s safety, JetMall does carry a padded carrying case.

As I mentioned in the previous section, the O2 features a full-size SDHC slot for increased capacity.  Such flash memory cards are available up to 32GB.  Combine that with the O2’s internal maximum of 32GB and you have potential for 64GB of total storage.  This is neglecting, of course, that you could keep multiple SD cards on hand for additional storage.  Whether or not SD cards larger than 32GB will be compatible with the O2 is unclear at this time since the SDHC spec calls for a maximum of 32GB, and the new SDXC spec was recently created to address the need for larger cards.  It seems unlikely that a firmware update could enable SDXC support on the O2 due hardware limitations in current SDHC controllers.

This is about all that can be surmised from just looking at the player, so let’s dig in a little deeper.


The first time you power on the O2 you will be prompted to calibrate the touchscreen by touching a series of nine points on the screen.  It will then ask you to choose a language and to check whether or not you live in the EU.


After you have done these few things you will arrive at the main menu.  This is the screen that you will see every time you turn the player on.


Let’s go straight to the feature you will use most…the music library.  Your files are displayed here in a directory hierarchy in exactly the structure that they were transferred to the player.  Since the O2 does not support sorting by tags, this is the only way to organize your music.  For some people that may be quite an annoyance, and it seems odd not to support tag-based sorting since the player does read the tags for info on the playback screen.  Fortunately the syncing software that I tested creates a proper directory hierarchy for you, so lack of tag support does not result in extra work on your part.  Furthermore, since the player doesn’t care about tags for sorting, it doesn’t really matter if you have songs that are improperly tagged.  Nonetheless, it would be nice to see COWON at least add the option for tag-based sorting in a future firmware revision.

By default, only the internal storage is shown in the browser initially, and this will be true every time you turn the player on.  To mount an SD card, touch the small SD icon at the bottom of the screen.  It will take several seconds to scan the card, but you only have to do this once while the player is powered; after that you can switch the SD card on and off without it rescanning.  The act of scanning the card is fairly intensive though, so if you have music playing while you switch to the SD card, playback will be halted until the scan finishes.

The file browser is navigated by double-tapping the directory you want to go to, and songs are selected for playback in the same fashion.  There are several ways to go back up the folder hierarchy, one of which is to touch the hierarchy list at the top of the screen.  Various other controls are located on a bar at the bottom of the screen.  The back arrow in the bottom left of the screen takes you back from whence you came, which in this case is to the main menu, and the ‘M’ in the bottom right of the screen will always take you back to the main menu.  The other controls on this bar from left to right are: climb folder hierarchy, display favorites list, add to favorites list, access SD card (as was mentioned above), delete, and summary of options (play, add to favorites, delete — a repetitive and unnecessary button, no doubt).


When you finally select a song and it begins playing, this is the screen that will appear.  If your songs happen to have album art, it will be displayed on the left-hand side of the screen; otherwise that space will instead be filled with a generic picture of a CD.  In either case, you can switch from the image to a real-time sound spectrum graph by touching the image once.


There is quit a bit more information shown on this screen.  At the top right are the song name, artist name, and album name, which the player actually extracts from the song tags, not from the filenames.  Below the names is a list of icons which represent the various playback mode settings: from left to right are directory boundary, repeat mode, shuffle mode, speed (.5x to 1.5x in .1 increments), and section repeat.  These settings can all be changed in two different ways.  The first is to tap their icons on the playback screen, which will allow you to cycle through the options for each.  The other way to change these settings is to go to the music options in the main menu, which I will show later.

I want to elaborate quickly on the directory boundary option.  The default setting for this is “All”, meaning that settings you apply for repeating and shuffling will operate on all the songs on your player.  I recommend changing this setting to “Sub-folder.”  If your stored music follows the directory hierarchy of Music → Artist → Album, then this setting will cause repeat and shuffle to apply only to the album to which you are currently listening.  If you change the setting to “Folder,” then it will instead work with everything inside the Artist directory (or whatever your highest parent directory happens to be).

In the next row down are the various audio output settings: from left to right are the bitrate and sample rate, equalizer mode, BBE, ‘Mach3’ bass enhancement, MPE compressed audio enhancement, and virtual 3D sound.  These settings also can be changed either from the audio settings panel in the main menu or from within the playback screen.  Simply touch the gear-shaped icon on the bar at the bottom of the playback screen.  You will be presented with a scrollable list inside the bar, which you can use to cycle through the various modes and applicable settings.

Lastly we have the controls.  The various playback buttons are obvious, the back arrow takes you to the music browser, and the letter ‘M’, as was stated earlier, takes you back the main menu.  The list icon, just as before, lets you add the song to your favorites list.


At the very bottom of the screen are some options which are always present except for when you are in fullscreen viewing mode, such as for videos or pictures.  One option here is the volume control, which lets you change the volume level and switch between headphones and the internal speaker.  Alternately, you can use the volume buttons on the outside of the player to change levels.


Also located on the bottom bar is a green musical note.  Touching this icon gives you popup window which allows you to control the music playback even when you aren’t looking at the playback screen.



Moving on, here is the video browser.  Selecting a video from the list will cause the player to display information about the file, such as size, resolution, codec, etc.  The control bar on this screen should look familiar, as it is identical to that of the music browser.


This is what you will see when a video file is playing.  The control bar is familiar, but there is a new addition.  The icon shaped like a TV with an arrow is the video output control.  You can only use this option if you purchased the USB-RCA adapter.  When you select video output mode, a message will pop up to inform you of the selection, and in a couple seconds both the video and audio will switch to only the output cable (the player screen goes blank and the internal speaker and headphone port go silent).  You can exit video output mode by simply touching the screen.

The gear-shaped icon is here again, but this time it controls entirely different features: aspect ratio, subtitles, amount of zoom, audio track, 3D stereo, playback speed, screen brightness, and screenshot capture.  The control bar autohides after 5 seconds, but you can manually hide and unhide it by touching the center of the screen once.


Although it’s difficult to demonstrate here with a photograph, the picture quality of the screen is excellent.


Here is the picture browser.  Selecting an image causes the player to display information from the image tag.


By default, pictures are viewed zoomed out to full aspect, but you can zoom in using the magnifying glass on the control bar.  You can also rotate the image using the circular arrow icon.  Pressing play will cause your pictures to cycle as a slideshow, or you can cycle through them manually with the forward and backward icons.  Lastly, you can hide and unhide the control bar by touching the center of the screen.




Returning to the main menu and touching the down arrow reveals a second list of icons.


The first icon is the file browser.  From here you can access all files on the player, whereas the other dedicated browsers (music, video, photos) were limited in functionality.


The sound recorder is straightforward to use and has adjustable encoding quality.


The programs menu lets you access any extra programs you might have on the player.  As of now, the only programs included with the O2 firmware are a calculator and a notepad.  As you can see here, I’ve added a 3rd party program that simulates popping bubblewrap.


Here is the calculator, which has standard and scientific modes.


Here is the notepad after having been put to good use.  A stylus comes in very handy.  There are no fancy tools or brushes in this program, but the size and color of the pen are adjustable.  You can also have multiple drawings, which are stored on the player as 24-bit bitmaps. 


Lastly, here is the bubblewrap program that I added.



Returning again to the main menu, here is the third row of icons.  The side arrows indicate that the list is wider than the screen; the ‘System’ and ‘Information’ icons are not shown here.  In the following images I will briefly comment on only some of the configurable settings (mostly just the important ones).


In the sound settings is a highly-customizable equalizer.  A number of presets are available, but you can manually adjust each bar to +/- 9.  As you can see I have chosen the flat preset.


Also adjustable are the corner frequencies of the equalizer filter and the width of each frequency band.  These bands correspond to the equalizer bars in the previous image.  This next image shows the default filter settings. 


As was mentioned earlier, the sound enhancement options can be controlled from this menu as well as from the playback screen.


Moving on to the video settings, we have a number of options to customize.



In the display settings you can control the brightness, color balance, and video output protocol.


In the system settings are several important options.  The first option controls playback resuming.  By default the O2 does not remember what you were listening to the last time you used it.  If you turn it off and back on, it will boot to the main menu and you will have to find the correct song and resume playback on your own.  Enabling ‘Boot Resume’ will cause the player to remember the song and progress when you turn it back on.

The second option, ‘Browse Resume,’ causes the player to remember what directory you were last viewing in the file browser.  If you do not enable this option, then the various file browsers will always start at the root directory, which can quickly become annoying, for example, if you are simply trying to select a different song from the same artist that is currently playing.

The third option controls the functionality of the external volume buttons when hold mode is active.  The choices are off, volume control, or playback control (skip forward/backward).


In the information menu you can view the firmware version and free space.


There remain a couple of icons on the bottom bar that have been ignored thus far.  First is the clock icon.  Selecting the clock allows you to adjust the date and time.  The other is the battery icon, which lets you choose to blank the screen or turn off the player.



This last image is the prompt that is given when the player is connected to a computer over USB.  If the player is on when you connect it, you are given a choice to mount the internal memory or the SD card.  If the player is off when you connect it, you will not be given a choice and the internal memory will be mounted automatically.


That concludes our look at the player itself.  Let’s now move on to other fun topics like firmware and software.

For any product that uses software, it is generally a good practice to stay up-to-date with the latest version, and the O2 is no exception to this rule.  Indeed, I strongly advise any purchaser of this player immediately update the firmware to the newest version.  Mine came with version 1.09a installed, and although the player was usable, it did have several problems and annoyances which have been resolved in subsequent revisions.  Those issues will be discussed in later sections of this article.

As I write this, the current newest version is 1.17.  When checking for updates, I recommend looking at both the US and global versions of COWON’s website, as it appears that the global site gets updated more frequently.  For the current firmware release it took over a week for the US site to be updated, during which time 1.14 was the newest revision shown.

For this review I have tested all three of the aforementioned firmware revisions.  However, I won’t get into the details of how to update the firmware because the process is very simple and is already well-documented.

COWON O2 Firmware Installation Guide

In the firmware updates so far I have seen only improvements (no new bugs), including greatly increased stability of the player.  However, in helping friends and family with their computers and various electronic devices, I have noticed some level of fear associated with updating firmware.  For that reason I want to urge the reader, don’t worry about it, just update.  If bug fixes alone aren’t enough to coerce you, the new firmware has another tweak that you will likely find handy – dragging the progress bar to seek through an audio or video file is now much faster and smoother.


Here’s that software mini-CD that I mentioned earlier:


The following screenshots illustrate what you can expect to see if you decide to install the JetAudio software.  I won’t go into much detail here since the review is more about the player itself, but I will show all important aspects of the software so as to give a decent overview.

First we have the main program window.  I found this interface to be similar to Winamp and dBpowerAmp in a number of ways.  Overall it is a solid program (no crashes so far!) with all the features you will need to manage your music and video collection.  Most features of the software can be accessed through buttons on the main window, rather than having to look through menus.


Here is the media library.  As you can see, it has all the playback controls that were present in the main program window as well as a compact version of the colored display at the top.  To the left of the display are controls for changing the layout of the library manager panels.  To the right of the display are buttons for the main software features, just as were present in the main program window.  The next few screenshots show each of these other features.


CD ripping tool:


Audio format converter:


Here is the video format converter.  The good news is that it has lots of preset options for different portable devices (including the iPod and PSP) so people with no knowledge of codecs can easily use it, and it also appears to be multithreaded to some degree.  The bad news is that you have to buy the pro version to convert videos longer than 30 seconds…or at least that was what the software claimed the first time I used it.  For some reason it still let me convert a full-length movie.  Now the message doesn’t come up, and so far I have converted three movies without any trouble.  I wish I had taken a screenshot of the message, but I instead closed it with the assumption that it would pop up again the next time I used the software.  Perhaps this is a bug of some sort?  I’m certainly not complaining.





Sound recorder:


CD burning tool:


This last screenshot is of the preferences panel.  There are tons settings to let you customize the program, but what I really wanted to show was the list of supported formats.


That concludes our look at the software.  Next up is a discussion of sound quality.



In order to test the sound quality of the O2 I compared it to my SanDisk Sansa e280 and to computer playback using Winamp and an ASUS Xonar DX sound card.  For each system that I tested, WAV audio sources were used (since that’s the only lossless format the e280 supports) and all equalizers and sound enhancements were disabled.  The headphones that I used were Sennheiser HD280 Pro circumaural studio headphones.  I tested parts of many different songs to check specific frequency ranges, such as "Slipping Away" by Dope for deep bass, "Don’t Bring Me Down" by Electric Light Orchestra for various treble sounds, and "The Longest Time" by Billy Joel for a chorus of vocals.

Initially I focused on just the two portable players, vigorously switching my headphones back and forth between the two, but I was unable to detect a difference in any of the songs.  Both players delivered powerful bass, clear mids, and clean, crisp treble.  My favorite song to test, by far, is "Torn Between Scylla and Charybdis" by Trivium because it contains an excellent variety of sounds to compare.  Most notable, at least for me, are the sharp snaps of the snare drums which pierce through the basslines and guitar solos.  Even these sounds were distinctly and accurately reproduced by both players.  For each song I also went back and compared each player to the computer’s sound output, and again I was unable to detect differences.  So there you have it, both players deliver superb sound quality.  You will definitely not be disappointed by the O2 in this regard.


To test the iAudio earbuds I compared them to those which were included with my Sansa e280 and iRiver IFP-899, and of course I still had the Sennheiser HD280s on hand as a reference for high quality sound reproduction.  I wish I could have used some iPod earbuds to compare as well since far more people are familiar with their sound than with SanDisk or iRiver headphones, but alas I made do with what I had.  I used the same set of songs for this task as I did for the player quality comparison.  All of the tests were conducted with the O2 using WAV audio sources, a flat equalizer, and all sound enhancements disabled.

The Sansa earbuds were inferior for all songs that I tested as they lacked strength on the low end and clarity on the high end.  The iAudio and iRiver earbuds, on the other hand, had a flatter frequency response and demonstrated similar sound quality in most tests.  The main flaw with the iAudio headphones is exaggerated lower-midrange instead of correct bass response, a common property of low-quality headphones which simply aren’t capable of reproducing low frequencies.  This problem was most apparent in the first 40 seconds of "Torn Between Scylla and Charybdis," in which the bassline progression came out booming and overpowered the other instruments.  The iRiver headphones were definitely the best of the three, and even those were not particularly good compared with my reference Sennheiser headphones.

Anyone who is reading this and cares about sound quality is probably shaking their head right now.  The truth is if that you want clean and accurate sound reproduction then you won’t be using the stock headphones anyway, and chances are you already own a quality set from the likes of Sennheiser, JBL, or Sony (or any of number of other brands).   Speaking hypothetically for a moment, if you did not care about headphone quality, then some of the most appealing features of this player also would not matter to you, which means you probably wouldn’t even read this review.  With that said, this comparison was not particularly important, and the only reason I even tested the stock earbuds was for the sake of being thorough.  Rest assured, those earbuds are now safely back in their box, likely never to be used again.


One aspect of PMPs that often remains unexplored in reviews is I/O performance, the speed at which files can be transferred to and from the device.  For many players and their users this is probably of little importance, since copying a couple hundred MP3 files doesn’t take very long.  However, the O2 is targeted at users who move large files around — lossless songs that average 30MB a piece, and full-length movie rips that may be several gigabytes in size.  When transferring large amounts of data, the I/O performance of the player becomes extremely important.

The O2 interfaces with the computer over the USB2.0 bus.  In theory this bus is capable of nearly 60MB/sec transfer rates, but in reality the peak transfer speed falls between 30MB/s and 40MB/s.  This was demonstrated quite thoroughly in a recent XCPUs article: Flash Drive Roundup: A Dynamic Review.  There are a number of reasons for this, such as host controller overhead in dealing with data encapsulation, as well as the fact that all devices connected to the same host controller share the total bus bandwidth.

I used HDTach to analyze the performance of the O2.  This tool only measures read performance, but since reads from flash memory are by design faster than writes, this provides a best case limit to the transfer speeds that you can expect to see.  Here are the results for both the player’s internal memory and the SD card:

O2 internal memory performance:


O2 SDHC performance:


As you can see, the results are quite disappointing.  At 8MB/s, the read speed for the internal memory is only one quarter of the potential maximum, while the SD card performance is even more embarrassing at a mere 4MB/s.  Keep in mind, this is still faster than USB1.1, which is rated at a maximum of 1.5MB/s.  Nonetheless, with results this sobering I wanted to be certain of my findings, so I ran the tests multiple times with different USB ports and different computers — the result was always the same.  These are also the same speeds that Windows Vista reports when transferring files to and from the player, so I am confident that they are correct.


The SD card that I used here is actually a µSD card with an adapter, so out of curiosity, I used a µSD-USB adapter to test the card independently from the player.  Here are the results of that test:

µSDHC USB adapter performance:


The card still does not reach the full potential of the USB2.0 connection, but it does prove that the O2’s USB controller is severely bottlenecking data transfers.  Unfortunately I have no way of determining whether this issue is hardware or software related.  While I hope that it can be improved with future firmware revisions, I won’t hold my breath for it, and I certainly wouldn’t recommend basing your purchasing decision on that possibility.  If you are interested in this player, be prepared to deal with slow transfers.

Out of further curiosity, I decided to test my old SanDisk Sansa e280 both for internal memory and µSD performance.  Please note that this player does not support SDHC, so the card in this case is standard µSD and is not the same card that I used to test the O2.  The results clearly show that the Sansa isn’t any better in terms of transfer speed

e280 internal memory performance:


e280 µSD performance:


I wish I had more players to test, but unfortunately I do not.  I have nowhere near enough data to draw any conclusions about the O2’s I/O performance relative to its competitors, so please just take these charts for what they are: a simple estimate of what you can expect to see if you buy the player.

This concludes our look at the O2.  The last couple sections of this review will summarize what I deem to be the pros and cons of the device.


So easy a normal person could do it

The O2 was effortless to pick up and start using without looking at any sort of instructions.  Granted, I did accidentally add songs to my favorites list several times before mastering the music library navigation, but let’s not dwell on my personal inadequacies.  The icons in the UI are generally obvious in meaning.  There are also multiple ways to perform common tasks.  A few examples:

– To change volume, you can use the volume buttons on the top external of the player, or you can select the volume icon and adjust it in software.

– To turn the player off you can click the battery icon at the bottom-right of the screen and then click “power off”, you can flick the external power switch once and then click “power off” on the screen, or you can slide and hold the power switch in the off position for approximately 2 seconds.

– To move backwards inside any of the file browsers you can touch the climb hierarchy button (looks like a folder with an up-arrow), you can touch the directory path at the very top of the screen, or you can double tap the directory labeled “..” at the top of the directory list.

Control freak

With minimal external controls, one would hope that the touchscreen interface is up to snuff.  Fortunately that is the case, as the screen is both sensitive and precise.  It should be noted that this device implements a contact-sensitive touchscreen like the Nintendo DS, not a capacitance touchscreen like the iPod Touch.  Using the included stylus, a pen (closed, of course), or even just your fingers, you can reliably hit desired on-screen items.  Regardless of your choice of touching device, be sure not to press very hard!  There’s no point in scratching or cracking your screen when it responds perfectly well to even the most delicate touch.

Holy encapsulator, Batman!

The O2 supports an extensive list of codecs and formats, something which has come to be expected from COWON products.  In fact, you will be hard pressed to find a PMP from any other company that supports as many formats as the O2.  Here they all are, taken straight from the specs on COWON’s website.  If this list is Greek to you, feel free to skip over, as the simple take-home message is that it supports a lot of stuff.

Video playback:

Video codecs

DivX 3.11/4/5/6, XviD, MPEG-4 SP/ASP, WMV 9/8/7, H.264, M-JPEG, MPEG 1

Audio codecs

MPEG1 Layer 1/2/3, WMA, AC3, OGG Vorbis, FLAC, BSAC, True Audio, WavPack, G.726, PCM

Wrapper formats


Music Playback:

Audio codecs

MPEG1 Layer 1/2/3, WMA, AC3, FLAC, OGG Vorbis, OGG FLAC, APPLE Lossless, True Audio, Monkey Audio, MusePack, WavPack, G.726, PCM

Wrapper formats


One thing that is missing from this list are DRM-protected files — they are unsupported.  To an audiophile this makes no difference, but to someone who buys music from iTunes or a competing online service it is a very big deal.  Sorry, your DRMed files will not play on this device.

Perhaps that most interesting aspect of the O2’s format support is that it doesn’t particularly care about the video resolution (though the absolute highest supported source resolution is 1280×720, or possibly lower depending upon the bitrate).  Videos that do not match the dimensions of the screen are scaled, cropped, and letterboxed as needed.  You can adjust this to some degree during playback by changing the aspect ratio between automatic, 4/3, or 16/9, but so far the automatic setting has worked fine for me.

This is all well and good, but let’s have a quick reality check.  Not everything in that list is going to just work, and I can’t even begin to test all the combinations of formats, wrappers, resolutions, and bitrates that are possible.  I have encountered some problems, which are described in the next section of the article, but overall this player does have very good compatibility with random video files in various formats.  For example, movies encoded to 700MB filesize with DivX or H.264 codecs play perfectly. 

Lastly, I feel it is worth mentioning that videos from Youtube are directly playable on this device with no conversion or hassles.  Simply use a site like, or any of a number of software tools, to download the mp4 video file to you computer.  You can then transfer the file to your player and it will work as is.  This feature does not belong solely to the O2, however, as any player supporting mp4 video should be capable of the same.  Indeed, current iPod products have been confirmed as working with downloaded Youtube videos.

Standard Issue

Don’t you just love when products follow industry standards instead of making you deal with proprietary nonsense?  Yeah, me too, which is why I was thrilled to find that the O2 uses a standard mini USB cable.  Whenever I go on a trip, I can take my O2 and my digital camera, and I only need to bring one cable for both of them.  And if I happen to lose that cable, no big deal, I’ve got at least 5 more of them at home from various other electronic devices.

The O2 is also industry standard when it comes to software.  The player shows up as a removable drive in Windows and Linux — I have personally verified this in Windows XP 32-bit SP3, Windows Vista 64-bit SP1, Fedora 9, and OpenSolaris 2008.11.  This means that under any such OS, you can simply drag and drop your files onto the player, or you can use any program that synchronizes with drives.  COWON includes its own software, jetAudio 7, but you are not forced to use it or to even install it for that matter.  The included software works fine for transferring files, as was detailed earlier in this article.  I have also tested the O2 with Windows Media Player 11 and Winamp 5.5, both of which successfully added files to the player.  Between these two, Winamp is my program of choice since it supports FLAC audio, but if you instead use WMA lossless then WMP is the more user-friendly choice.  However, my overall preference is to just drag and drop files since I already sort my music collection manually anyway.

Music to my ears!

The sound quality of the O2 is simply excellent.  When compared with sound output from my Xonar DX, a sound card widely known for quality sound reproduction, I was unable to detect any difference.  I also tried out the various music enhancement options, although I did not discuss them in this article.  I personally prefer to just use a flat equalizer, but if you want to tweak any aspect of the sound, the equalizer and preset enhancements give you unrivaled flexibility to do that.  Paired with a good set of headphones, this player is capable of clean and accurate sound output that will not disappoint.


Does. Not. Compute.

When navigating menus or adjusting settings, both during and not during file playback, the device sometimes hangs for a couple of seconds and then shuts itself off.  Fortunately when this happens it’s not the end of the world.  So far I have not encountered a lockup with any repercussions; the device is back to normal operation as soon as you turn it back on.  I have also noticed that the device will sometimes stop playback when attempting to seek through a file or when the screen automatically blanks to save power.  This hangup can usually be recovered from by dragging the progress bar backwards a bit, hitting pause, then hitting play again.  It seems to me like there are some relatively minor firmware bugs that remain to be worked out.

This problem has been greatly improved upon with new firmware revisions, and crashes have gone from fairly common to quite rare.  I have found that the device no longer hangs on its own during playback, but it sometimes still locks up when settings are tweaked.  COWON has been making good progress with the firmware, now they just need to make a bit more.

Format Woes

The player claims to support a number video formats, and while most videos I have tested worked perfectly, there are others which have proven somewhat problematic.  First, while I’ve had no problems with DivX videos, for some Xvid files I have seen the video stuttering and desynchronized from the audio.  Perhaps this is a firmware issue, or perhaps it’s just a quirk with the videos I have tried.  Most of the Xvid files that I tried worked perfectly, but a few did not.  I’ve also yet to get Matroska videos to work, but again, this could be an issue with the encoding settings.  I don’t have the resources to investigate these problems in depth, but I wanted to make sure the reader is aware that things are not entirely peachy.

SD doesn’t automount

Another bit of annoyance with the O2 is that the SD card is not automatically mounted when the player turns on.  When navigating any of the file browsers, you can click on the SD icon at the bottom of the screen, which then causes the card to mount and become viewable.  This is relatively minor though and quite tolerable.  However, with the stock firmware (v1.09) the real problem was that the SD card also did not mount when the player was connected to a computer over USB, and thus the only way to get content onto the card was with a card reader or other compatible device.  For me this was particularly inconvenient because my card reader is several years old and does not support SDHC cards.  Fortunately this problem has been fixed in firmware v1.14a.  If the player is connected by USB while turned off, it will automatically power up and mount the internal memory.  However, if the player is turned on and then connected by USB, the player then prompts the user to select either the internal or SD memory to be mounted.  Another improvement has been made in firmware revision 1.17b — once the user has mounted the SD card, it will remain mounted until the player is turned off, whereas in previous revisions the card had to be remounted every time it was accessed.

Are we there yet?

As I described earlier, the USB transfer rate for the O2 is extremely disappointing.  Transfers to internal memory and SD memory were respectively demonstrated as being 1/4 and 1/8 the typical transfer speed of USB2.0 devices.  Assuming the best case speed of 8MB/s, it would take over an hour to fill the player’s 32GB capacity.  It is saddening that a PMP with such promise in terms of video codec support would be crippled in its ability to copy large files in a reasonable amount of time.  Basically you’ll just have to be patient and only transfer files when you are not in a hurry.

Tag, you’re it!

The last thing that I found disappointing was the fact that the O2 does not have an option to sort music by tags.  Since the player relies entirely on the directory hierarchy for sorting, your files will need to be organized as such on the player.  Fortunately Winamp, Windows Media Player, and jetAudio are all capable of creating the directories for you when syncing files to the player, even if the files were not organized in any way on your computer.  Still, sorting by directories is only good if you like to play entire albums straight through.  Many people, however, like to play a mix of music, which is more easily accomplished with tag sorting.  Furthermore, the player does not seem to support playlists that are generated by any of the aforementioned media programs.  The only solution I have found for mixed playlists is to construct one manually using the favorites list.  This list is preserved between player reboots, but you can only have one list at a time.  This is something that really should be addressed in future firmware updates, lest many prospective users be deterred.

I’ve never been a fan of writing conclusions because they seem to imply that all the other information presented is somehow less important to read.  Nonetheless, I need to state some sort of verdict for those readers who either skimmed or skipped the other sections.  I’ll try to defy my own nature here by keeping this brief.

The O2 has its share of annoyances as were outlined in the previous section of this review.  Overall though I am very happy with the player and I believe that the $300 (I bought it before the current sale started) was very well-spent.  The O2 does exactly what it was advertised to do — little more, nothing less.  The real judgment call to be made is not whether the O2 is a good player, but whether it is suited for your interests.

If you want a player that supports lots of formats, has excellent sound quality, and can grow in storage capacity along with your music collection, then look no further; the COWON O2 will not disappoint on any of these fronts.

On the other hand, if you were looking for something inexpensive, compact, or stylish, then you have likely realized by this point that the O2 is not for you.  Fear not though, COWON may still have something that’s right up your alley — they call it the S9.  I won’t get into the details here, but suffice to say that it’s a closer competitor to the iPod Touch than the O2 will ever pretend to be.


I would like to say a quick thank you to the following individuals:

– Casey Dougherty, for his knowledge of flash and USB devices.  His article "Flash Drive Roundup: A Dynamic Review" and personal feedback were helpful in writing the I/O performance section of this review.

– Sevag Hanssian, for testing the iPod Nano with Youtube mp4 videos.

– Larry Klein, for his 2006 article "How to Judge Speaker Quality with Listening Tests"

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