48k sample rate files

rvltion909 · Post by **rvltion909** » Sun Mar 02, 2008 10:37 am

I recently riped a bunch of Itunes files off CD at 48k.

They now play at a sped up rate. Im not sure exactly why this is but I know Ableton plays these files...how can it play them at the standard speed (aside from turning the tone down)?

Anybody have experience with this

noisetonepause · Post by **noisetonepause** » Sun Mar 02, 2008 11:04 am

What's playing them back faster? iTunes? Live?

And they were standard audio tracks, that'd play in a CD player, which you ripped to 48 khz WAV? Or what?

It's weird that they're playing faster, it should be the opposite. Liek, the app is reading that data as 44.1 so it should play it slower. From what you describe it sounds like the files aren't really 48 khz files..

rvltion909 · Post by **rvltion909** » Sun Mar 02, 2008 11:05 pm

everything plays them back faster (Live, Itunes, Winamp)

And they are being seen as 48k files by Live. What I did was burn all my itunes files to cd then riped them as 48k, 16bit wav files...now they play back sped up?

rvltion909 · Post by **rvltion909** » Tue Mar 04, 2008 6:17 pm

I really need some help here. Im at a loss I've already tried to "resample" them down to 41k with an app. called "r8brain" that is supposed to be a rate converter. It made no difference.

I've messed with my sound card settings (setting it to 48k then back to 41) nothing helps. I tried burning them again and ripping to 41k-nothing.

I've got 160 songs here that I've lost the source files to so Im now stuck with all these tracks that play at high speeds.

Im desparate here guys

Funkstar De Luxe · Post by **Funkstar De Luxe** » Tue Mar 04, 2008 6:22 pm

Why did you rip a CD at 48Khz?

rvltion909 · Post by **rvltion909** » Tue Mar 04, 2008 7:46 pm

lack of understanding of audio technology overall

laird · Post by **laird** » Tue Mar 04, 2008 8:00 pm

You are giving us some bad info.

1st: You ripped itunes files off a CD.

I assume you mean you made a bunch of m4a files from an audio CD.

your audio CD is at 44.1 Khz (not 41 like you keep typing).

Question is: did your ripping program (itunes?) resample your audio when it tried to make some 48kHz m4a files or not? Sounds like it did, but I'm not sure.
Or is the playback problem just a playback problem. Some apps can't play back 48 kHz compressed audio files... and will just play back a 48khz file at 44.1khz (which will sound slower).

Unless you can figure that out, your easiest bet is to just re-rip the dang files and do it right.

laird · Post by **laird** » Tue Mar 04, 2008 8:03 pm

Also, Live can play those files just fine by turning the pitch down (and using pitch mode, not any of the time stretching modes). Thats the same as changing the sampling rate (unless your ripping app "resampled" your audio files at the wrong sampling rate, i don't think it did but I don't know since the problem could be a playback, not an encoding, error)

rhythminmind · Post by **rhythminmind** » Tue Mar 04, 2008 8:21 pm

If your files really are 48k but sound fast. All you have to do is change the header information back to 44,1.
Open something like wavelab and change the audio rate back to 44,100. But DO NOT RESAMPLE. This isnt the problem. If you resample you will just have fast resample audio. You need to trick the files back into 44,100

Things like this can happen if you have your soundcard locked to 44,100 and you have you DAW session @ 48.
But how you did this with itunes i have know idea

rvltion909 · Post by **rvltion909** » Tue Mar 04, 2008 9:38 pm

laird wrote:You are giving us some bad info.

1st: You ripped itunes files off a CD.

I assume you mean you made a bunch of m4a files from an audio CD.

your audio CD is at 44.1 Khz (not 41 like you keep typing).

Question is: did your ripping program (itunes?) resample your audio when it tried to make some 48kHz m4a files or not? Sounds like it did, but I'm not sure.
Or is the playback problem just a playback problem. Some apps can't play back 48 kHz compressed audio files... and will just play back a 48khz file at 44.1khz (which will sound slower).

Unless you can figure that out, your easiest bet is to just re-rip the dang files and do it right.

What I did was burnt all my Itunes files (m4p) to audio CD. Once they were burnt to audio I ripped them with a "free-ripper" and chose the 48k sample rate, 16 bit wav option. I then burnt them to a DVD and reformatted my PC.

So now I have wav files that are being read as 48k by Live and Winamp (the files display the 48k indication). My soundcard (Delta 66) has an option to be set to 48k. I've tried using this and it makes no difference. I've tried 2 PCs (my laptop with standard on board audio and my DAW with the Delta 66).

I also tried burning them back to audio CD with Itunes then ripping them back to 44.1. There was no change. I've since burnt other Itunes files to audio CD and used the same ripper to rip them as 44.1 16bit wav files and these sound fine.

rhythminmind · Post by **rhythminmind** » Tue Mar 04, 2008 9:41 pm

Did you read my post? You have to change the metadata/file headers. They are 44,100 audio in a 48k container.

rvltion909 · Post by **rvltion909** » Tue Mar 04, 2008 11:16 pm

rhythminmind wrote:Did you read my post? You have to change the metadata/file headers. They are 44,100 audio in a 48k container.

Sorry, I did and I will try that when I return home tonight. Hopefully that is it!

rvltion909 · Post by **rvltion909** » Wed Mar 05, 2008 6:34 am

OK that did it!

Thanks rhythminmind. What I did was open it up in Audacity then choose the "set rate" option and it played back at normal speed.

The only thing I didnt find was a way to alter the information in the original file so that it sets this playback rate back to normal permanently (which is what I thought you were telling me to do). Its not in the metadata editor...that just seems to be the artist name, track title, tag option.

The only way there seemed to be to save the change was to "export" the wav file. However, when I do this, it makes a new file...a slightly larger one at that.

For example, the file I opened started off as a 42,504kb file. The exported file was 46,259kb

Is this right?