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ASIO on PC & Mac with iTunes & Apple Lossless

Ignorance is bliss and I was too stupid to know it. I did an A/B test with my CD drive optically connected to my DAC1 and computer/waveterminal connected to the coax port. All my music is in iTunes ripped with Apple Lossless Codec.

The DAC1 has a nice little switch that allows me to switch immediately from one source to another. So I started the same song in the CD and on iTunes and started A/B swapping.

The PC with k-mixer was shockingly bad. With the CD, the stage was big and deep. Switch to the PC and the stage collapsed and it sounded like half of the richness disappeared. It was clear, unambiguous and really bad.

I monkeyed around and tried some generic ASIO drivers but it seems that I couldn't really get any better quality out of my PC. I'm not sure that iTunes ever picked up the ASIO drivers at all, even though I had installed the Waveterminal drivers.

I got sick of PC fun and dragged an old iMac into the picture. The drivers don't appear to be ASIO for OS X - and are in beta since 2003. The A/B test with the Mac was better than the one with the PC, but it is still anemic, especially at the low frequency range.

So - here's the questions:

1) Can anyone tell me of a sound card or other solution that can bypass the k-mixer in Windows and use ASIO?

2) Once I have that - is there a way to force iTunes to use that driver? Right now, most ASIO apps have a special dialog box that you configure to use the drivers. iTunes has no such dialog box.

If you can suggest an all-Macintosh solution - that's okay too.

Thanks,

Daryll.

System
Benchmark Media DAC1
U24 Waveterminal
Threshold T-200 Amp
B&W 803s
Either PC or Mac
dfogal
brooks
55 posts
 
When using the iMac, why do you have to use drivers? Because of the Waveterminal? I use an ibook straight to a usb dac....no drivers, no nothing...it just goes and sounds great. Having to go to spdif really screws everything up doesn't it? Why aren't modders out there offering to add usb inputs into dacs already in the market?
Steve
dfogal OP
3 posts
 
Update from a friend of mine...

XP has four methods for outputting audio via an audio device. DirectSound, WaveOut, ASIO, and kernel streaming.

DirectSound and WaveOut go through kmixer. ASIO and kernel streaming don't.

Depending on which output you pick, you get what you get.

Going through kmixer = not bit perfect.

iTunes/XP is a pure DirectSound/WaveOut application. It uses QuickTime as it's I/O processor, and all the filters and codecs are buried in QuickTime. They don't register as codecs in XP. This is important in that the Apple Lossless Codec can't be used by other programs.

The only QuickTime options I can get to show up are DirectSound and Wave Out. I cannot patch in an ASIO plug-in.

Even if I use S/PDIF out, there is still a Windows volume control present, which means kmixer is active. Even if you don't have Windows XP volume control panel active, kmixer still may be active.

The only real test I've found to determine if kmixer is active is to play a DTS/DD encoded bitstream to my Fosgate /Audionics FAPT-1 Pre/Pro and see if it will decode it properly. If Bit perfect, it will decode. I cannot get iTunes to do this using any soundcard I have, including the M-Audio Delta 410, an 8 channel 24bit 96 kHz card.

Even if there is no kmixer, the soundcard you choose MAY RESAMPLE. Means that you could put in a 44.1 kbps .wav stream, only to have the soundcard upsample to 48kHz and then downsample back to 44.1 kHz ARGHHH!!! Many of the Creative Labs SoundBlaster cards do this because all their processing algorithms only work in a 48 kHz 16 bit space. All of the AC3 soundcards do this, and most output stereo audio as a 48 kHz bitstream.


Now the conjecture:

Proprietary applications may bypass kmixer. Some RME cards may do this, perhaps by using the kernel streaming function in XP. Sounds plausible, but.....no one has confirmed it will work with iTunes. Need to verify.

USB audio devices are just like any other audio device to XP, and have the same options (directsound, waveout, asio, kernel streaming). With iTunes and XP, since ASIO and kernel streaming are NOT options, then, even with USB, you are not bit perfect.


Conclusion:

There is no proven bit perfect solution for iTunes on a PC based platform.

This leaves the following options:

1.) Convert Apple Lossless files back to .wav files, and check for bit-perfect output via direct file comparison.
2.) Buy a MAC.
3.) Hope that future versions of QT will allow an ASIO plug-in. (Unlikely due to the Apple plug-n-play philosophy.)
4.) Hope that someone will supply an ALC equivalent as a stand alone codec.
iamoneagain
3 posts
 
Hopefully Foobar 2000 0.9 will be finalized so it can get ASIO support. Right now the beta version will play Apple lossless, so once it's released, an update to the ASIO will be added.

http://www.foobar2000.org/ click on the beta link

There is also this program that lets itunes control foobar so you would get bit-perfect sound but with the itunes interface. The two problems could be: does it work with foobar 2000 0.9 and does it work with itunes 5.0.

http://www.aqua-soft.org/board/showthread.php?t=27275

I haven't found an Apple Lossless codec that works with the current release of foobar.

Hopefully soon this will all be worked out. I just tried a cd using ASIO output and it was a little more detailed and clearer. I don't think itunes output is that bad, so I'll live with it until foobar is ready.
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