XLD vs iTunes Time Coding

[Teramac]

Have not seen anything related, apologies if this is an old issue.

 

Some early imperfect rips in iTunes convinced me to switch to XLD to create my lossless files (ALAC). Having the error check displayed seems a nice feature you don't get in iTunes and it has worked well for 1,000s of files....until now. My rips are stored on a networked hard drive in an iTunes library. I routinely play those with iTunes, stream them to a Naim Uniti, or play them on a Sonos system.

 

I recently discovered one file that plays at a noticeably slower speed on my Sonos amp:connect with an obvious key change. The same file from the same location plays fine with iTunes. A rip of the same CD using iTunes to ALAC produces a file that plays correctly on both systems. A second rip of the same CD using XLD reproduces the error. Since it is reproducible, I'm left wondering which of my files might play slowly if I'm using the Sonos. (There's some chance that Sonos may investigate this but since it only happens with XLD, their initial advice is to switch to iTunes.)

 

Has anyone seen this behavior with XLD? I assume there's timing that is part of the codec but not a clue how the various ripping apps encode that. Is there any software that can analyze my rips to determine if the timing flags are correct or not?

 

Any thoughts appreciated.

[pooger]

I don't have an answer for you—but welcome to CA! Hopefully someone will have a clue. Do have a question—is the slower play always accompanied by frequency change? With digital timing issues, the two are generally not linked.

[Daudio]

I assume there's timing that is part of the codec but not a clue how the various ripping apps encode that. Is there any software that can analyze my rips to determine if the timing flags are correct or not?

 

Any thoughts appreciated.

 

The only timing information that I know of that is embeded in a digital audio file are the 'Sample Rate' and 'Bit Rate' fields. You can see them (but not change them) in iTunes metadata editor. I'm not that familier with other metadata editing programs, but they are probably the same in that respect.

 

When you described your problem the only thing I could think of that might remotely cause your symptoms would be a possible confusion in the software between 48k and 44.1k sample rate, or maybe a mismatch between the sample and bit rates, that only the Sonos is confused by.

 

That's all I've got. Good Luck

[Teramac]

Hadn't even considered that playback speed and frequency were independent in the digital world. Yes, the files play more slowly on Sonos than with iTunes and they also have a frequency shift down, essentially like a turntable at the wrong speed. Maybe the belt is slipping on my D/A converter?

[kumakuma]

What sample rate is XLD set to?

[Axiom05]

What sample rate is XLD set to?

 

This may be the key. The Sonos can handle both 44.1 kHz and 48 KHz sampling. If the recording is encoded at a higher bit rate, e.g., 96 kHz, the Sonos will play it at 48 kHz, with the resulting playback sounding at half speed. Really bizarre sounding.

[Teramac]

XLD is set at a bit rate of 48Khz and a bit depth of 16. The slower speed is nowhere near 1/2, just enough to make a female vocalist sound a bit masculine. Maybe the Sonos is confused between 48K and 44.1?

[Axiom05]

XLD is set at a bit rate of 48Khz and a bit depth of 16. The slower speed is nowhere near 1/2, just enough to make a female vocalist sound a bit masculine. Maybe the Sonos is confused between 48K and 44.1?

 

This may just be a quirk of Sonos, it does happen. I have a recording that on one track the Sonos will not play the last several seconds, it just mutes. I have tried everything to remedy this but nothing has worked. The file plays with no issues on every music player that I have tried, except the Sonos. It also doesn't matter if I use flac or ALAC. Go figure...Probably not worth losing sleep over, use your iTunes rip and enjoy the music. One last thought, are you using the latest version of XLD?

[kumakuma]

XLD is set at a bit rate of 48Khz and a bit depth of 16. The slower speed is nowhere near 1/2, just enough to make a female vocalist sound a bit masculine. Maybe the Sonos is confused between 48K and 44.1?

 

If you are ripping a CD, the sample rate should be set to 44.1, not 48, so perhaps this is your problem. With XLD, it is best to leave the Sample Rate and Bit Depth settings to "Same as original".

[goldsdad]

Hadn't even considered that playback speed and frequency were independent in the digital world.

 

They are not independent. Reducing playback rate will lower pitch, as in the analogue world.

 

 

XLD is set at a bit rate of 48Khz and a bit depth of 16. The slower speed is nowhere near 1/2, just enough to make a female vocalist sound a bit masculine. Maybe the Sonos is confused between 48K and 44.1?

 

You should be ripping CDs at 44.1 kHz 16-bit, anyway, if you want bit-perfect rips. Set XLD to "Same as original" for sample rate and bit depth unless you specifically want it to resample.

 

 

Edit: beaten to it

[Axiom05]

Why does the file play correctly with iTunes?

[goldsdad]

Why does the file play correctly with iTunes?

 

Because iTunes will play a 48 kHz file at 48 kHz, or resample to another output rate (see next paragraph), so the pitch will be correct although the file doesn't contain a bit-for-bit replica of the 44.1 kHz audio on the CD.

 

Depending on the computer's audio settings (see Audio MIDI Setup Utility), iTunes and/or the OS, or neither, can be resampling audio before it is sent to the DAC at a given rate. So, considering the CD was ripped at the wrong sample rate, there will be between one and three resamplings between CD and your DAC.

 

To get bit-perfect reproduction from CD to DAC when using iTunes on a Mac, you make sure to rip at 44.1 kHz and ensure the computer's output rate is set to 44.1 kHz before launching iTunes.