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CD ripping sample rate.
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Dakar
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Oct 2, 2006, 01:13 PM
 
Is there any advantage to ripping at 48 khz vs 44? I've noticed that my optical output on my iMac seems to output to my receiver at 44 khz despite what my mp3 may be.
     
analogika
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Oct 2, 2006, 06:57 PM
 
CDs are 44kHz, 16 bits.

If you convert to 48kHz, you're actually performing a sample rate conversion, which is great computational effort for actual (measurably, though hardly audible) loss in quality if you're going to anything other than straight multiples.
     
Dakar  (op)
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Oct 3, 2006, 08:19 AM
 
Ah, thanks for coming through analogika. Looks like it was a worse deal than I thought.

Now, for $200, what would be the optimum sample rate when I use a program like, say, handbrake, for DVDs? They function at a higher khz, yes?
     
analogika
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Oct 3, 2006, 06:03 PM
 
DVDs' ac3 audio is generally sampled at 48kHz.

In the end, it doesn't really matter what you rip the DVD at, since it'll be converted anyway when you output to regular 44kHz audio output.
     
stevesnj
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Oct 3, 2006, 07:31 PM
 
If you intend to use your music collection in Final Cut Pro you should use 48kHz. I found this out the hard way (popping in the audio track after burning to DVD) but now I rip all my cd's at 48kHz.
MacBook Pro 15" i7 ~ Snow Leopard ~ iPhone 4 - 16Gb
     
analogika
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Oct 4, 2006, 03:09 AM
 
How do you rip CDs at 48kHz?
     
Dakar  (op)
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Oct 5, 2006, 03:07 PM
 
Originally Posted by analogika
DVDs' ac3 audio is generally sampled at 48kHz.

In the end, it doesn't really matter what you rip the DVD at, since it'll be converted anyway when you output to regular 44kHz audio output.
Thanks, again alalogika


Originally Posted by analogika
How do you rip CDs at 48kHz?
Well, it is an option under iTunes.
     
Doofy
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Oct 10, 2006, 07:25 AM
 
Originally Posted by Dakar
Is there any advantage to ripping at 48 khz vs 44?
Dakar, here's a tip: If you can't tell the difference between a 320 kbps MP3 and a CD, then you're not gonna hear that extra khz anyways (even on a system which allows you to play it at the higher rates). For most people, anything above 44 is pointless - it's just higher numbers for the sake of it.
     
Dakar  (op)
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Oct 10, 2006, 08:24 AM
 
Well I can usually hear the difference when I play it through my home sound system.

I'm trying to save myself the aggravation of ripping some stuff twice.
     
Doofy
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Oct 10, 2006, 04:41 PM
 
Originally Posted by Dakar
Well I can usually hear the difference when I play it through my home sound system.

I'm trying to save myself the aggravation of ripping some stuff twice.
Arh, OK... ...the extra KHz would be worth it to you then - if you had the gear to play it. Unfortunately, as analogika says, you're somewhat limited to 44 for the time-being. For CDs, ripping at 48 is simply adding "spacer" information which isn't there in the original recording - there's no gain in doing so at all.
However, if you've already ripped 'em at 48 and don't want to redo at 44, there's no real problem leaving them as is (aside from a bit of HD space wasted).
     
Dakar  (op)
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Oct 11, 2006, 11:40 AM
 
Originally Posted by Doofy
Arh, OK... ...the extra KHz would be worth it to you then - if you had the gear to play it. Unfortunately, as analogika says, you're somewhat limited to 44 for the time-being. For CDs, ripping at 48 is simply adding "spacer" information which isn't there in the original recording - there's no gain in doing so at all.
That's what I was guessing when I learned about the CDs being 44 (after I had already ripped a few at 48).

Originally Posted by Doofy
However, if you've already ripped 'em at 48 and don't want to redo at 44, there's no real problem leaving them as is (aside from a bit of HD space wasted).
Thanks, I agree.

Like I said above, now I'm curious if its worth encoding DVD audio at 48 (Handbrake, etc.) . If the iMac is capable of outputting at 48khz at all, that is.
     
qnxde
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Oct 11, 2006, 01:56 PM
 
There is absolutely no point ripping a 44khz source (CD audio) to 48khz, it's just extra work for no gain whatsoever. Also note ripping at 48khz may cause incompatibility with some portable players (although im sure the ipod would handle it fine).

The extra bandwidth achieved by encoding at 48khz vs 44 allowing you to sample up to 24khz instead of "only" 22 is pointless, as there is no audible data in that frequency anyway. Most CD's are lowpassed at around 20khz when pressed to prevent aliasing anyway.

You can't eat all those hamburgers, you hear me you ridiculous man?
     
Dakar  (op)
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Oct 11, 2006, 02:20 PM
 
Ok thanks, this question has been answered 3 times. I now have a new question if anyone wants to tackle it.
     
analogika
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Oct 11, 2006, 06:49 PM
 
Originally Posted by Doofy
Arh, OK... ...the extra KHz would be worth it to you then - if you had the gear to play it. Unfortunately, as analogika says, you're somewhat limited to 44 for the time-being. For CDs, ripping at 48 is simply adding "spacer" information which isn't there in the original recording - there's no gain in doing so at all.
Woah there.

You're thinking of increasing the bits per sample - converting from 16 to 24 bits, for example, can be done in several ways. You can just add an extra empty 8 bits to the 16, or you can *dither* the 16 bits across the 24, which is a lot more work for very little gain (excuse the pun).

A SAMPLE-RATE conversion is ALWAYS "dithered" or interpolated and broken up, and inherently results in audio degradation to some degree. There is no "spacer" information added.
     
analogika
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Oct 11, 2006, 06:52 PM
 
Originally Posted by qnxde
The extra bandwidth achieved by encoding at 48khz vs 44 allowing you to sample up to 24khz instead of "only" 22 is pointless, as there is no audible data in that frequency anyway.
*ahem*

Aside:
Studies involving seem to indicate that high-frequency sound up to 40 kHz *is* in fact somehow perceived and processed by the brain (blind tests show increased cerebral activity when the ultrasonic frequencies are not filtered out), but that's not really relevant to this discussion.
     
   
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