iTunes and bitperfect

[godbreath]

I have a pc desktop, and i heard that the using spdif with iTunes does not give you bitperfect. I was just wondering, what does iTunes do with the signal exactly, and if I use usb, will the signal be bitperfect then?

 

[krmathis]

iTunes can output bit-perfect to the optical S/PDIF.
Just just have to make sure 'Sound Enhancer', 'Sound Check' and the EQ are turned off, and the volume are set to 100%.

That is if your PC run Mac OS X. If it runs MS Windows I am not sure if its still bit-perfect, since it probably route through KMixer

 

[godbreath]

what is the KMixer? and will using usb also have the same problem?

 

[krmathis]

KMixer is the the Kernel Audio Mixer driver in MS Windows.
First hit on Google

-> Windows legacy audio components - Wikipedia, the free encyclopedia

I think USB audio go through KMixer as well, but not certain.
Tip! When asking computer software related questions its worth mentioning which OS you run, to reach the correct persons right away.

 

[.Sup]

I bypassed kmixer with asio

 

[myinitialsaredac]

I used Wasapi and Multi plugin

Dave

 

[godbreath]

Quote:

Originally Posted by krmathis /img/forum/go_quote.gif KMixer is the the Kernel Audio Mixer driver in MS Windows. First hit on Google -> Windows legacy audio components - Wikipedia, the free encyclopedia I think USB audio go through KMixer as well, but not certain. Tip! When asking computer software related questions its worth mentioning which OS you run, to reach the correct persons right away.

I use windows vista ultimate

Quote:

Originally Posted by .Sup /img/forum/go_quote.gif I bypassed kmixer with asio

Quote:

Originally Posted by myinitialsaredac /img/forum/go_quote.gif I used Wasapi and Multi plugin Dave

is it possible to use those plugins with itunes though?

edit: i did some googling and it seems like multi plugin for itunes is dead now

 

[Brewmaster]

Itunes can output bitperfect in Windows with many sound cards.

Works with the Auzentech Prelude, and from what I have read many of the X-fi cards, as well as other cards with Envy chipsets etc.

Just make sure you have the appropriate audio control panel settings enabled (ie. output at 44.1, bitmatched playback). Volume must be maxed in audio control panel and application.

If you have a receiver that can decode DTS audio, download a DTS wave file (Google) then test if it plays in Itunes.

 

[HD_Dude]

Good thread!

 

[Shoreman]

Quote:

Originally Posted by Brewmaster /img/forum/go_quote.gif Itunes can output bitperfect in Windows with many sound cards. Works with the Auzentech Prelude, and from what I have read many of the X-fi cards, as well as other cards with Envy chipsets etc. Just make sure you have the appropriate audio control panel settings enabled (ie. output at 44.1, bitmatched playback). Volume must be maxed in audio control panel and application.

In reference to the PC platform, I believe this is incorrect. I could be wrong, but the above contradicts everything I have read/heard up to now on this issue. I believe that's why many are so frustrated with itunes, because they can't have the pleasant interface along with bit-perfect (non-resampled by k-mixer) audio.

 

[godbreath]

Quote:

Originally Posted by Shoreman /img/forum/go_quote.gif In reference to the PC platform, I believe this is incorrect. I could be wrong, but the above contradicts everything I have read/heard up to now on this issue. I believe that's why many are so frustrated with itunes, because they can't have the pleasant interface along with bit-perfect (non-resampled by k-mixer) audio.

thats what i thought also, but isnt there an airport express than can stream the music from itunes? how does that work like how does it connect to your pc, and will it only stream itunes music, or can you use it to stream all the other sounds?

 

[iamoneagain]

Quote:

Originally Posted by godbreath /img/forum/go_quote.gif thats what i thought also, but isnt there an airport express than can stream the music from itunes? how does that work like how does it connect to your pc, and will it only stream itunes music, or can you use it to stream all the other sounds?

With the airport express, you can stream any itunes libraries you have on your wireless network. It will be bit-perfect from a pc or mac. I know on a mac you can use airfoil to stream the sound of any program. They may have a pc version.

You can also use an iphone or ipod touch as a remote for the airport express. You can choose which library and where you want to send the sound if you have mutiple units. It's a very nice interface.

 

[apatN]

Yes in Windows you will have to bypass the kmixer. Simplest thing is foobar and either Kernel Streaming, ASIO or WASAPI.

 

[krmathis]

Quote:

Originally Posted by godbreath /img/forum/go_quote.gif thats what i thought also, but isnt there an airport express than can stream the music from itunes? how does that work like how does it connect to your pc, and will it only stream itunes music, or can you use it to stream all the other sounds?

Yes, you can stream to the AirPort Express from iTunes.
The audio data will be converted to Apple Lossless (if its not already) on the fly in iTunes, then streamed via WLAN (wireless network) to the AirPort Express. The AirPort Express can then output bit-perfect to a DAC through its optical S/PDIF (digital) output.
Its called 'AirPort', and afaik it don't go through KMixer at all on MS Windows.

 

[Brewmaster]

Quote:

Originally Posted by godbreath /img/forum/go_quote.gif thats what i thought also, but isnt there an airport express than can stream the music from itunes? how does that work like how does it connect to your pc, and will it only stream itunes music, or can you use it to stream all the other sounds?

I actually bought the Auzentech Prelude on a leap of faith after finding out bitperfect could be enabled on at least some X-fi cards. If you waste enough time searching the internet the info is out there.

I just retested this using a DTS wave file, and verified it decodes correctly on my receiver, directly out from Itunes. Sure beats messing around with ASIO or KS and being forced to use players that support those output modes. No knock against Foobar or any other player, it's just nice to not have to deal with this issue and not worry about plugins etc. in various applications.

I'm not sure if the X-fi control panel is similar but I've included a screen shot of my setup with the Auzentech. Key points are that master sampling rate set to 44.1 and bit matched enabled in the settings. In addition, on the main screen as shown, all inputs muted, master volume maxed and volume maxed in Itunes. If I drop either volume slider below 100 bitperfect is lost and the wave file sounds like static. If I enable any inputs bitperfect is also lost.