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View Full Version : Lossy Source For Commerical CD?


latestheartbreak
2010-10-24, 02:14 PM
When ripping a CD I happened to do a frequency analysis and thought it odd that the frequencies on the whole CD cut off at just over 21 khtz. Isn't this a bit odd? I've never seen it before. Could this be lossy at all?

co9ol
2010-10-24, 03:02 PM
A CD only has a frequency responce from 20hz-20khz (ish) it is suppose to cut off like that. Check your other CD's, they should be the same. DVD audio on the other hand has the capability to go much higher than that.

latestheartbreak
2010-10-24, 03:12 PM
CD goes up to 22khz (hence why the graph goes up to 22khz). I often check the frequency response on Audaicty when I rip CDs and they never cut off early unless they're from a lossy source.

rspencer
2010-10-24, 05:28 PM
If it's a commercial CD, that's just how it was mastered. I wouldn't be surprised to see it rolled off lower than that.

latestheartbreak
2010-10-24, 06:44 PM
I was wondering if it was down to the mastering, but what would the purpose be of that? I have an unmastered version of one of the tracks, and the frequencies don't cut off that low. There are also some live tracks that cut off like that from the same artists. Is there nothing in the Spectrum graph to suggest it being lossy?

rspencer
2010-10-24, 08:06 PM
If it was lossy (say, mp3 sourced) it would cut or roll off much lower. Lots of times mastering is done without taking full use of the audible range. Commercial mastering is a compromise. It needs to sound good in as many situations as possible (crappy little radio speaker, cheap headphones, hi-end speakers, car, etc.).

What is the original source (and what time period)? The original mix of Electric Ladyland was done & then Kramer told Hendrix it wouldn't work. Jimi liked the bass to slam, & when pressed the needle would have jumped off the record. :lol: So they had to tone it down.

co9ol
2010-10-25, 06:35 AM
As far as I have herd, CD's are only suppose to go from 20-20 and that extra bit at the top is a safety band because if any frequencies that are above that get into the system, they can make huge problems.

latestheartbreak
2010-10-25, 07:08 AM
If it was lossy (say, mp3 sourced) it would cut or roll off much lower. Lots of times mastering is done without taking full use of the audible range. Commercial mastering is a compromise. It needs to sound good in as many situations as possible (crappy little radio speaker, cheap headphones, hi-end speakers, car, etc.).

What is the original source (and what time period)?

But are there any other lossy formats that get frequencies up to there? What purpose would there be to master something like that, when it can't possible have any positive effect?
The album is from this year and was recorded the previous year I believe.

As far as I have herd, CD's are only suppose to go from 20-20 and that extra bit at the top is a safety band because if any frequencies that are above that get into the system, they can make huge problems.

No, CDs go from 20khtz up to 22 htz - the standard frequency range for CD/44.1. If you check 99% of CDs, the frequencies will cut off abruptly at 22 - not gradually before it.

Five
2010-11-09, 11:36 PM
latestheartbreak you are right.

audio cds can go up to 22500kHz. I've seen one or two like this official releases that cut off at 20kHz for no reason I can understand. I could never figure it out, either :lol:

maybe the sampling rate was set wrong somewhere earlier down the line?? setting it to 44.0 instead of 44.1 would result in this kind of an abrupt cutoff at 20kHz (Nyquist).