The following will neccesarily be somewhat superficial and a lot more can be said about the subject but for the sake of keeping this article readable, I'll cut some corners here and there. Nevertheless, the conclusions are valid and should be taken serious, although they do become less evident on less than stellar audio systems.
Audio file formats come in many forms for use on the pc. All these differ in quality, but it also matters which application is used to play them back with. Sounds incredible? Read on!
*What's more: the bitrate isn't even the most important aspect of mp3. Even a 96kbits/s file can sound really decent while a 320kbits/s file, made in a mediocre programme can sound really bad. 128k can soud pretty decent and is good enough for most people. Audiophiles of course need higher bitates, preferably the highest possible: 320k. And since hard drives are getting larger and cheaper, there's no reason not to use the highest possible quality and that's wav. But if you're stuck to mp3, all is not lost. Even at 320kbs there is still a substantial difference with wav, but not in the sense of a different sound of in the shape of sizzling, phasey highs. These well known artefacts definitely don't have to be there, as long as a quality decoder is used. If you have a good hifi system you can hear the differences easily. The largest differences between good mp3 and wav are: less spaciousness (3D), less focus and less detail. Also the transients are often a little rounded off, making the sound subjectively slower and less dynamic. But lo-fi it absolutely isn't!
The following programs have excellent mp3 encoders:
-Easy mp3 encoder
And there are many oher programs in which Fraunhofer or Lame encoders are used.
mp3, wav, flac:
mp3, wav, flac:
Most well-known are of course wav/aiff and mp3. Apart from these there are compressed lossless formats such as flac. Wav and aiff are essentially the same format, only the headers differ, the data is identical. Both are uncompressed and reperesent more or less cd quality. mp3 is usually compressed to one fifth of the original file but can still sound surprisingly good, as long as the encoding and decoding is done carefully (*). This is the clincher. A lot of ripper programs of the past have been notoriously bas at encoding. Even when selecting high bitrates. For example the program called Audiocatalyst was used a lot. It is very userfriendly but has bas encoding. Because of this a lot of mp3's you download now are less good than they can be.
Fortunately, lately the encoders get better and better. For example iTunes uses the encoder from Fraunhofer, who is the developer of many matters mpeg, mp3 included. Flac is compressed but in a smart fashion. Rather than throwing away data, it seeks to just compress all the data, much like Zip works.
Playback of a file can also be done well, or mediocre. This depends on the bundled decoder of the chosen playback application. Many readers will now scratch the back of their heads but really, this is true. I've done multiple tests and the differences are real. Not only the decoding of mp3's can be done well or not so well, this also goes for flac and even... for wav/aiff. You read that correctly: even wav. Such a native format for which most of the processing is done with standard windows software surely cannot sound different when played back in different playback software on the same pc? Sorry but really it does. Flac sounds very good but not entirely equal to wav/aiff. In my tests wav/aiff are tighter whereas flac tends to be more rounded, a bit like mp3. Actually flac sounds somewhat more fluid than wav/aiff and for that reason, on lesser systems, can actually sound better than wav.
So the application matters?
Indeed. I know how strange this sounds because most playback applications use standard Windows libraries and therefore there should not be any difference. So what causes these differences is unclear to me. I suspect that secretly the signal goes through lots more cozy places than we think. No doubt it is converted many times and in the case of some programs probably too much or the wrong processing takes place.
All apps sound different. Even between winamp 2 and winamp 5 there is a large difference, big enough to be heard over computer speakers! Luckily this difference is explainable. The old winamp 2 could easily be made to clip when you played with the EQ too much. the newer winamp 5 never overloads. Never! This indicates a processor present somewhere in the loop. You can actually switch off the so called clipping prevention but this doesn't help. Presumably the software is still "in circuit" even when switched off and thje data still gets rounded off. This is comparable to the situation where windows always had the kernel-mixer in place to convert any samplerate to the same mixed output. This makes for bad sound but also for a volume reduction. Apparently you can only reach 99.9% of the level. Which should be fine you think. But it isn't. Luckily the kmixer can be bypassed using better audiocards and the right settings. But that's another story.
On mac very good; on Windows XP less features, bad processing and playback only up to 44khz. More info*
In comparison to winamp 2 sharp, phasey and restrained.
Better than mp3 but still flat, rounded and boring.
Doesn't play FLAC and no other high res either.
Nice balans between focus, control, tightness, fluidness and absence of digititis. More info**
excellent decoding, our reference
Also very good: fast, open, detailed, dynamic. Only mildly rounded and that's actually not such a bad thing.
Does not play flac
Nice interface, plays everything, does everything. Sounds fluid and supple but is restrained and dynamically compressed.
All tend to sound relaxed with slightly loose bass, like Mediamonkey but more dynamically restrained. Sounds flatter and therefore less exiting. More info***
All formats sound very accurate but I miss a bit of musicality. Compared to Winamp 2 mostly fullness in the bass and fluidness/spaciousness are missing. Compared to Mediamonkey and Media Jukebox the last two are most obvious.
Plays all formats, works well, sounds very well balanced.
Lighter on its feet, more soft and has less attack in the bass than winamp 2 but more fluid. More body in the bas than Media Monkey.
Same result as with mp3
Fuller in the bass than the other apps. Nice balance.
Not as slick to use as Media Jukebox but its fluid and airy sounds makes it worth using.
A lot like Media Jukebox but a bit airier and agile. Most fluid of all apps.
Sounds even more like Media Jukebox than with mp3. More lively and airy than mp3.
Thin in the bass but also most agile, fluid and airy.
What are the tested applications and what are the results?
Playback with high resolution 192k flac file "misery" (free download at HD tracks), and playback of various selfmade, ripped and downloaded wav's and mp3's.
Please note that the short observations right below were made with default settings for all apps. It turned out later that you can get significantly better performance from iTunes and Winamp 5 by using the correct settings. More info and new comparisons are down below.
Conclusions and more info
The programs I like best for sound:
For me winamp 2 is still the best player, with iTunes behind it since I found out about the Quicktime settings that it relies on. Winamp 2 comes closest to playback in a dedicated wav editor in which the file was made. Too bad that thiss app cannot play flac, although there may be plugins for this.
** Update august 2010: Winamp has many settings. Of much importance is the one where you choose your preferred soundcard but also very important is the waveout setting. You should avoid Windows soundmapper but can choose between Directsound and Wave out. Unlike in iTunes, Directsound sounds much softer and is altogether undynamic and uninspiring. In addition, Winamp 2 sounds liveliest if you avoid upsampling and/or filtering of any kind.
Mediamonkeyand Media Jukebox
The choice between these comes down to taste. Mediamonkey plays almost to the same standard as winamp 2 but is on the one hand softer in the bass, with less attack and on the other hand it is softer in the high frequency, which is actually not such a bad thing because this makes it more friendly to bad recordings. Media Jukebox is a well-balanced sounding application that has a very nice interface and plays everything to a high standard. I guess you could call it neutral and it is an excellent alternative for Winamp but I kind of like the special fluidity of Mediamonkey. Even though you could call it less neutral.
Getting the most from Winamp 5:
I didn't like Winamp 5 before, due to its dynamic compression. Shame, because otherwise it's very well-behaved, having smoother highs than winamp 2. But it is way too rounded off and lacks dynamics and expressiveness. Please note: this observation was done with standard settings.
*** Update august 2010: I installed the latest version (5.58) and found no difference in sound quality. But after some more digging, I managed to find some settings that make a profound difference for the sound quality. If you set them as I will explain below, Winamp 5 will sound more similar to iTunes on Windows (again, with proper settings), which makes it an app that I can recommend after all.
1.) plugins - output - select your soundcard or device directly, don't use windows soundmapper, disable volume control.
2.) plugins - input - nullsoft module decoder - enable FIR interpolation (HQ) instead of Interpolation
3.) General prefs - Playback - disable 24bit playback
With these settings winamp 5 has finally lost its "compressed" quality. The feeling that the music was playing with the hand brake on is now all but gone. Everything sounds much faster and more dynamic while maintaining the smoother character Winamp 5 has over winamp 2, which may be drier but is also still more exciting to listen to. Winamp 5 now sounds mature and is an excellent choice if you like some smoothing of your music. Winamp 5 is the fullest sounding playback app of the bunch.
Getting the most from iTunes on Windows:
This one really is easily the worst program of the bunch. No doubt this has to do with conversion and compatibility with windows XP. On the Mac iTunes is actually excellent. But please note: this is with default settings.
* Update august 2010: Actually, iTunes for Windows turns out to rely on the settings made in Quicktime player. In there you can specify the bitrate and samplerate and make iTunes capable of playing high res files. If you specify 92kz and 24 bits iTunes will upsample (or downsample) all material to that bitrate. Upsampling does a nice job at adding a hint of air and more ease, at the expense of a bit of tightness. Very much a matter of taste. While you're at it, in QT settings you can also change the output from Directsound to safe mode (WaveOut only). Officially Directsound should be better but in this case "safe mode" sounds much fuller and livelier. You cannot however, choose a specific soundcard and therefore cannot bypass Windows' kmixer, unless you use a third party program and do some programming. I use the program "Virtual Cable" to make a direct connection between iTunes and my preferred soundcard. This bypasses all Windows-related mixing and conversion but doesn't bypass iTunes' filters, amongst which is the bitrate and samplerate setting done in Quicktime. But when used like this, all of a sudden, soundwise, iTunes comes in right next to my still slightly preferred Winamp 2! Done this way, iTunes has a nice relaxed feel, with excellent fluid highs and full, round bass. It doesn't have all the tightness and rhythm of Winamp 2 but iot becomes a matter of taste now, not so much a matter of absolute quality anymore. I am really glad that I found out about this because iTunes is operationally very pleasing to use.
On a side note: in Windows 7, iTunes has more or less the same features. Or lack thereof. In other words: in Windows 7 you still cannot choose your preferred soundcard in the QT settings.
This program takes a special place. I personally don't like it but this is personal because this player is actually very accurate and also has options for upsampling and kernel streaming. For me its sound is a bit too controlled and too dry. Much like a digital sounding cd player. But there may be people out there that have less open and detailed playback systems that may tend to the dark of sluggish and on those systems Foobar may even be preferred.
I want to stress that the results published here are valid in my system. Surely their comparative and relative differences will still be true on other systems but please keep in mind that everything is very system dependent. But at least I think that I have made clear that there are indeed large differences to be heard amongst the various audio playback applications.
After the large audible differences that I found using the various playback applications and their settings, and their dependence and relative validity depending on the rest of the system and the consequent mess that this has created, I decided to undertake a second comparative test, this time using both Mac and PC as well as all currently popular playback applications and a handful of add ons for these applications. On top of this, I used not only my EMU 1212M soundcard but also USB solutions like M2Tech's HiFace EVo, Arcam rDAC and the very special Ayre QB-9 USB DAC. Using these components, I repeated all tests done above and with this report I will provide a clearer, more comparative overview. This turned out to become one of my most elaborate tests ever. For the result, look here: File formats and playback applications compared - part 4 - Mac versus PC