Optimising Windows Audio Playback

[PJPro]

Ok. I'm an IT professional. But I'm not an expert on Microsoft audio architectures. Nonetheless, I have done a little research into this and have produced this posting to provide some pointers for setting up Windows to optimise audio performance.

Windows XP

Windows XP provides a number of layers of software to process computer audio. This software architecture can/does impact the quality of the sound reaching the soundcard.

For example, Windows XP will support a number of concurrently running applications. Each of these applications may produce sounds. These sounds need to be merged together and sent to your soundcard for broadcasting. The software responsible for mixing of audio streams is the Kernal Mixer (or KMixer).

To simplify the job of mixing lots of sounds from different application, the KMixer resamples everything to 48kHz even if it is already at 48kHz (and doesn't make the best job of it). So your 44.1kHz audio stream from your media player is no longer bit perfect.

To get round this (and the latency introduced by all the operating system software) you need to enable your media player to connect directly to your sound card. To do this is you use Audio Stream Input/Output (ASIO) or Kernel Streaming.

To use either ASIO or Kernel streaming you need to have a plugin available for your media player of choice. These are available for Foobar2000 and WinAmp (ASIO, Kernel Streaming ). I am sure that many others exist (though see iTunes below).

Windows Vista

The audio software architecture is different in Vista. It has been completely rewritten to address some of the issues with Windows XP (see here). There is no Kernel Mixer in Vista.

The architecture provides an Application Programmers Interface (API) to support bit perfect streaming to the sound card. This is the Windows Audio Session API (WASAPI). It provides capability which is similar to kernel streaming but does not require the programmer to write complex kernel streaming code.

WASAPI supports two modes of use: shared and exclusive. In shared mode, audio streams are mixed and global effects (if specified) are applied before the stream hits your sound card. In exclusive mode the audio streams are not mixed and no effects are applied i.e. the audio stream from your media player is passed directly to the sound card.

To use WASAPI you will need a plugin for your media player and your sound card will need drivers to support it. Currently, I only know of Foobar2000 that has a WASAPI plugin. This operates in WASAPI exclusive mode only. The Creative Soundblaster XFi range supports WASAPI (but please check your specific model).

I have produced a How To thread detailing how to setup Foobar2000 to use WASAPI in Vista here.

See this thread if you want to use ASIO4ALL or find out a little more about the audio architecture in Windows (XP & Vista).

Mac OS X & Linux

Don't know a great deal about these but they do not seem to have as many of the mixer issues as Windows (perhaps supporting Ashley James's view that Apple desktops make a better audio source than PCs running Windows?).

iTunes

If you are running iTunes within Windows you are going to have the same issues as all other media players. Unfortunately, you are not able to work around the KMixer (in XP) or use WASAPI directly (Vista). If you desparately want to keep the iTunes frontend but want to improve sound quality you could check out this page. It details how you can set up iTunes to use Foobar2000 as a backend processor using the Multi-Plugin. I haven't tried this myself.

Sound Cards

It is worth noting that once you have set everything up to bypass the upsampling performed by windows that your sound also probably upsamples to 48kHz (check it's setting). If you can, set your sound card to 44.1kHz. If you can't, the upsampling performed by the card may be impacting sound quality. If you are using Foobar2000 you can add higher quality upsampling plugins to do the sample rate conversion rather than letting the sound card do the upsampling. I use this one. EDIT: Found out over the weekend that my X-Fi soundcard has an updated control console available allowing the selection of 44.1kHz, so I no longer need the upsampler

That's about all I know. Hope it is of use to someone.

31/12/2010 - UPDATE - iTunes & WASAPI
It would appear the iTunes now supports WASAPI on Vista and Windows 7 (32 bit versions). To enable WASAPI support, open Quicktime and select Edit | Preferences | QuickTime Preferences | Audio tab. You can select Windows Audio Session under "Play Audio Using." Some quick research on the web suggests that only shared (rather than exclusive) mode is provided. This means that your music will only be bit perfect if no other audio streams are present.

 

[PJPro]

Slightly surprised at the low number of views this thread is getting. I can only conclude that

1) The number of users who use PCs as an audio source is not as high as I expected.
2) The majority of users who do use a computer as an audio source use an Apple computer.
3) Forum visitors are not interested in improving the quality of their computer based audio.
4) The thread got buried quickly and visitors are unaware of the computer based audio forum.
5) The title of the thread does not accurately convey the intent of the posting.

Which do you think it is?

 

[Alec]

Well i like it

 

[PJPro]

Thanks al7478. But don't get me wrong. I'm not upset cos people don't like what I've said. People don't know what I've said cos not that many people have looked at it. I find that surprising and wondered why?

 

[Anonymous]

Good question.

1. Maybe the people who attend these forums who solely use computers as their source use itunes?

2. Maybe the people who use Windows as their source see themselves well versed in the subject?

3. Maybe no ones really bothered Mac/PC once their music is already playing?

4. Maybe no one likes you?

ÿ

Personally I'd like to see responses to all these questions [Except the last one in which I was only kidding].

 

[PJPro]

Lol.

1) Maybe. But you can use iTunes within Windows and, as I stated above, with a bit of effort..

2) Agree. But even experts would have a look to see it what I was saying was wrong.

3) Maybe. I wondered if many people regard the PC as a substandard source (MP3, etc) so can't be bothered with improving its audio quality. They'd rather spend some money on some speakers.

4) Highly likely. I seem to have a knack of putting my foot in it or upsetting people on this site without even realising it.

 

[Alec]

Tis a mystery. thing is, i find it hard to settle down to put the advice into practice. ive only learnt to use pcs grudgingly at all, as a means to an end, so there are people far more savvy than me who woulod think now of it.

Mr Pro, dya fancy coming over for the weekend 2 sort my pc out?

 

[Anonymous]

Personally I would prefer a site such as this, an all encompassing one stop shop!

It would help if those at WHFI, the reviewers of such computer based sources would chip in here and post.

However, I do realize that those at WHFI probably can't spend a huge amount of time giving tips on DIY htpc systems and components compared to off the shelf solutions etc, and that would probably be left to computer based magazines...

I myself am planning a DIY htpc + server/NAS solution to play all my ripped cd's and dvd's, furthermore my goal would be to download all my HD film content as I am looking to cut out BD as a medium and storage, as well as future music (hi-res), however it would seem that as yet there is no complete solution that is satisfactory.

I have spent a lot of time researching various configurations and solutions, but so far I have not yet settled upon the media software to play all the content I require to the standard I require unless I have a few boxes and various media software, which defeats my goal of a one stop solution...

So far I have settled upon a DIY pc based solution as far as hardware is concerned, however, I have one eye on a mac mini solution if the hardware is refreshed and the media software would allow a more modular approach in regards to codecs and would allow for true 'audiophile' playback.

 

[PJPro]

Fumanchu:
Personally I would prefer a site such as this, an all incompassing one stop shop!

It would help if those at WHFI, the reviewers of such computer based sources would chip in here and post.

I suspect that there is more expertise in the forum community than necessarily within the WHFSV staff on this particular topic. It's surprising the number of IT professionals within the forum.

 

[Anonymous]

It's a good post PJPro, and I bet many windows users do not realise the missing potential they have.

On my PC system I now use XP/ Winamp and Asio, through an external soundcard (Roland Edirol UA 1EX), optical cable to Beresford DAC, and an Argon HA1 Headphone amp to Sennheiser HD595 headphones. Audio lubblyness.

(The cheap as chips Argon is a bargain gem imo, and improves greatly on the headphone amp in the Beresford, even if I find it a touch bass-shy)ÿ

ÿ

(I use Winamp over foobar as I am a lastfm subscriber )ÿ

 

[Anonymous]

PJPro, this is a good post, I suspect that many people are using a mac, as I am, or are too put off by the complexity of windows to consider it as a source. Certainly there are none of theÿup-samplingÿissues on a mac.ÿThe cheapness of something like the Apple TV with its digital optical out might also have an influence. The majority of my friends use a mac as a source for digital audio.

However I'll mention this post in a blog post I'm writing and add it to delicious etc, thanksÿ

 

[Anonymous]

Lots more in this vein on the computeraudiophile websiteÿ

http://www.computeraudiophile.com/mac_pro_osx_windows_vista_ultimate_64_bitÿ

 

[PJPro]

Good resource.

 

[PJPro]

pudley:
It's a good post PJPro, and I bet many windows users do not realise the missing potential they have.

On my PC system I now use XP/ Winamp and Asio, through an external soundcard (Roland Edirol UA 1EX), optical cable to Beresford DAC, and an Argon HA1 Headphone amp to Sennheiser HD595 headphones. Audio lubblyness.

(The cheap as chips Argon is a bargain gem imo, and improves greatly on the headphone amp in the Beresford, even if I find it a touch bass-shy)ÿ

ÿ

(I use Winamp over foobar as I am a lastfm subscriber )ÿ

Where'd you get your headphone amp? Can't seem to find it online.

I'd like to get the Stello HP100 (to compliment the DA100) and am seeing if I can strike a deal with the UK retailer for buying the two.

Also quite interested in the Little Dot Mark V. Dual mono headphone amp for £159 off ebay and it appears well received by a number of reviewers on dedicated headphone forums.

 

[Anonymous]

I wouldn't take it personally PJ, I gave up offering or asking for advice on this forum a few months ago as I found that generally either no answer is given or when an discussion was developed, with myself or another user, it tended to be around how poor a system was and how you would not get an acceptable sound without spending £1000s.

I also consider myself to be a IT Professional but am pleased to say I have learnt something from your post. If that is true with Vista it's about the first thing I've heard that makes me consider updating.

 

[pete321]

I once hated the idea of having to play music via my PC, but eventually gave in for a couple of reasons, my CD collection became too large and I got fed up getting up and down playing 1 song from one CD then putting another in etc., and secondly, cheaper larger hard drives meant that ripping to a lossless codec was not an issue. I know use my upstairs PC with iTunes Apple Lossless for transfers to my iPod and music back-up, downstairs is the home built HTPC using Vista Media Center and predominently WMA Lossless via digital coax to my Onkyo receiver.

Plus points: I now find I'm listening to more of my music collection for longer, quick and easy to change tracks.

Down side: not as good sound/fidelity wise as a decent CD player, fan noise.

I've found I get more detailed sound by sending a 96KHz digitally to my receiver which I play using the Onks Direct mode, I've found 44.1KHz to be too flat sounding.

 

[Anonymous]

pete321:

fan noise.

Have you thought about 3rd party fans/cooling? and passive PSU's?

 

[PJPro]

pete321:
I've found I get more detailed sound by sending a 96KHz digitally to my receiver which I play using the Onks Direct mode, I've found 44.1KHz to be too flat sounding.

OK. Perhaps someone can help me out here. Why would an upsampled audio stream sound better? Isn't this gonna simply add stuff that isn't there.....like converting an MP3 file to WAV?

Note the following statement from Cambridge Audio regarding the new DAC Magic

"Adaptive Time Filtering (ATF), developed in conjunction with Anagram Technologies, Switzerland, intelligently interpolates standard definition 16 bit CD or USB audio to 24 bit/192kHz via a new 32 bit Texas Instruments Digital Signal Processor (DSP) to reveal unparalled levels of detail."

Surely, this is a fancy way of saying that it guesses what should be there when it isn't actually there?

I guess that all/most DACs do this and it's the differing algorithms used which contribute to the differing qualities of sound reproduction from CDPs.

Of course, this just serves to underline the limitations of the CD! What we really need are downloadable tracks which are already at that definition...so no guessing is required.

 

[professorhat]

PJPro:OK. Perhaps someone can help me out here. Why would an upsampled audio stream sound better? Isn't this gonna simply add stuff that isn't there.....like converting an MP3 file to WAV?
I guess a good analogy is an upscaling DVD player - all this is doing is adding stuff that isn't there. A really good one can actually make a DVD look much better though, so there's definitely something in it.

 

[Anonymous]

Variable bit rate is how MP3 was meant to be done, and a good idea of how the compression and upscaling actually work would help to judge.

Good to know, had no idea about the kmixer in XP, and I have foobar. Give it a go.

 

[PJPro]

whorlsy:
[snip]...Good to know, had no idea about the kmixer in XP, and I have foobar. Give it a go.

How did you get on?

 

[PJPro]

Sitting here now listening to Canon by Pachelbel, I cannot see how my PC system could be improved. It sounds absolutely brilliant and yet I know that there is much more to come....better DAC, headphone amp and headphones.

Almost bagged a Sugden Headmaster off ebay the other day but got sniped with 3 seconds to go. Damn!

 

[chebby]

Thanks for the article PJ.

I am using my new Fubar II USB DAC (16bit, 44.1 - 48khz) and iTunes 8.0.2 on Win XP Pro (SP3).

It is a plug 'n play DAC with no software or anything else to do. It just automatically defaults to be the soundcard when switched on and thats it.

It sounds great and iTunes (lossless rips & 256kbps iTunes+ files) sounds fantastic. Even Youtube can sound suprisingly good!

However all this talk of KMixer and ASIO4ALL got me intrigued. (The... "Am I missing anything despite it sounding great" syndrome.)

Well fine, I prefer iTunes so I cannot use ASIO4ALL (it looked nice & simple and free so that's a shame).

I don't want to change from using iTunes, I cannot change from XP Pro to Vista on this laptop (despite being my own machine, it is used for work so has to be XP Pro) and our iMac lives in another room from the hifi and swapping machines just is not an option for so many reasons (not technical but family/logistical) so I am stuck with Kmixer it seems.

IS this a problem if I cannot hear a problem? I have checked the iTunes/Quicktime settings and they are set at 16bits and 44.1khz, my lossless rips are 16 bits and 44.1khz so where is the problem?

The DAC is plugged into USB so how would I NOT be getting a bit perfect stream especially as the internal soundcard is completely bypassed?

People have DACs that 'upsample' to as much as 24 bits and 192 khz, so how does an upsample to 48khz (assuming that is actually happening) harm the sound?

Wish I had never seen any mention of kmixer before! Now I want to know if I am missing anything.

I think I will 'borrow' the iMac from the other room when everyone is out and rip an identical lossless file to it's iTunes and swing the DAC's USB cable between both machines to compare.

Or maybe blissful ignorance is a better state. I am really happy with the sound of the Fubar II USB DAC connected to iTunes on my laptop. So I think I should leave well alone.

 

[Anonymous]

Cheers, just optimised media monkey with a ASIO plugin, don't notice a difference in sound, but thought I would give it a try.

 

[russ74]

Well after a few weeks/months of tinkering and trying whats available (for free!) I've finally settled on what works for me:Hardware: NEC Desktop PC running XP (SP3) set up as media PC - sit 2m from screen.Media Player: MediaMonkey (free version, standard theme - Glided with the big orange play button, very usefull).Plugins: Winamp Kernal Streaming plugin v3.63. MAD MP3 v0.2 plugin & standard monkeymedia plugins for other codecs. I believe most winamp plugins will work in MediaMonkey.Others: MediaMonkey community developed software add on's (Scripts - see mediamonkey forum): Case Checker - checks and modifies tags (capitals, small a, etc) & web lookup - allow a full websearch from a list of sites for the selected/playing artist, album & track.Outside of PC: USB soundcard (PC has low profile case so only takes 1/2 height cards)) using optical out into an Ebay DIY DAC (contains just the pcbs, transformer and cables, no case) from Hong Kong which cost £36, upgraded opamp to National Semiconductor LM4562NA. Looks a bit 'rustic' in an old metal external cd case and duck tape but sounds great. This is connected to a variety of amplifiers - currently my Leak 3400 receiver.Overall I'm finally happy with the sound and quite enjoyed some of the tinkering along the way including the fustration of getting WMA 11 to accept and display all the codecs and to bypass kmixer (achievable but unstable in the long term).It's finally time to stop tinkering and start really enjoying the music.

On a side note I found all the methods of by-passing Kmixer in XP improved the sound quality no end especially on analogue before I got the DAC. Not sure how great the improvement would be if the DAC had come first, so if people are fully set up with Itunes & DAC and are happy it's probably safer to stay put than start endless tinkering.Enjoy