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Author Topic: Why record at 24/48 versus 24/44.1?  (Read 19587 times)

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Offline Jammin72

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Re: Why record at 24/48 versus 24/44.1?
« Reply #30 on: August 02, 2009, 10:01:09 PM »
If your goal is a CD I see no reason to record at 48 or 96.  Personally I like to archive and listen on DVD and 24/48 or 24/96 is the format for that particular medium.  It's interesting that when we're talking about recreating live sound that everyone wants to limit or draw lines around the range of human hearing. That doesn't happen in a live environment, frequencies much higher and lower than the ones we perceive though our ears interact with and affect the sounds that we do indeed hear. Why wouldn't we want to attempt to include those in trying to capture a truly live sound? I have a feeling that transducers on either side of the equation will (and have) step up and be able to include that information.

I don't know if it's the processors in my humble stereo system or simply one set of genuine placebo earmuffs but the 24/48 files sound better than their 16/44.1 counterparts on my playback system.

For someone asking the question the way you're phrasing it however, record at 44.1 there's no reason to use 48 if your ultimate goal is a CD. 24 bit gives you the headroom that has been mentioned and also provides for larger chunks of data for DAW work which I've found to be beneficial.

Always love the voice of reason in a DSatz visited thread.
Yes, but what do you HEAR?

Offline Jammin72

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Re: Why record at 24/48 versus 24/44.1?
« Reply #31 on: August 02, 2009, 11:54:00 PM »
You should check out some of Tannoy's super tweeters.  They have them as tack on units as well as integrated into some less expensive speakers.  Those combined with a concentric driver do wonders for image creation and cohesion IMO.
Yes, but what do you HEAR?

Offline DSatz

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Re: Why record at 24/48 versus 24/44.1?
« Reply #32 on: August 03, 2009, 09:07:04 AM »
Let me try to give a viewpoint from a non-hobbyist perspective. The audibility or audible effect of "supersonics" (not a term that's well accepted by audio engineers, incidentally) is controversial only in the sense that evolution is controversial: The evidence has been in for a long time and nearly everyone who has studied it agrees about it, but there is a determined opposition that keeps trying to come up with evidence to the contrary. That evidence keeps being shot down by other, later studies but there is often a period of time in which some tantalizing experimental result that might just indicate that there's some truth to the theory is still in play.

Creationists know that if they can find one feature of living organisms which scientists can't explain how it evolved, they'll win some converts. So they keep switching from complex feature to complex feature (bird flight, the human eye, etc.) and then after a while, researchers come up with evidence for the effect of natural selection in the development of that feature. Whereupon the creationists change to a different feature. Can they sustain their movement this way? Maybe, though they don't do themselves any real honor.

There is very good engineering reason to be concerned with the way systems handle signals at frequencies well above the range of human hearing. When such signals are present, they must not dirty up the audible stuff. And systems which limit bandwidth on purpose must do so in ways that preserve the sonic integrity of the in-band material. But there is no credible evidence, despite insistent claims and attempts to prove otherwise, that human beings can hear beyond about 20 kHz at anywhere near reasonable sound pressure levels--or that the presence or absence of "sound" above the human hearing range otherwise affects the perceived quality of audible sound, as long as it's not interfering (e.g. if you add a lot of 30 kHz, some amps go into audible slew-rate limiting).

In situations like this the only thing that can be said in the end is that the vast majority of serious audio engineers don't believe it, based on available evidence.
« Last Edit: August 03, 2009, 09:10:57 AM by DSatz »
music > microphones > a recorder of some sort

Offline DSatz

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Re: Why record at 24/48 versus 24/44.1?
« Reply #33 on: August 03, 2009, 09:00:38 PM »
mshilarious, I'm not making an ad hominem comparison; I'm comparing the degree of substance behind the two alleged controversies, and saying that in the audio engineering community this isn't generally considered to be one at all. Rather, the limits of the human auditory range are generally considered to be elementary, well proven and well settled--even the Oohashi study that you refer to cites sources to that effect across a range of 55 years in its first sentence.

It's just as in biology, where evolution isn't generally considered controversial. Creationists are a tiny minority among scientists, but almost any creationist will sincerely believe that a much larger number of scientists agrees with him.

That is a very understandable human attitude, I find. Few of us can say "I believe in something which the vast majority of knowledgeable people utterly reject on the basis of overwhelming evidence," without varnishing it with such additional layers of goop as, "Genius is always belittled, and truth must struggle to come to light in a sea of darkness ..."

I'm fond of people who have unusual and non-conforming ideas, yet in my circle of audio engineering acquaintances I can think of only one person who definitely believes in the audibility of sound above 20 kHz, and he was the director of sales and marketing at Earthworks (Eric Blackmer). At least his commercial activity was consistent with his ideals!

I've got the published report of the Oohashi study right here; I anted up and paid the download fee to the American Physiological Society five years ago and read the whole thing. It does NOT claim that people can hear above the 22 or 26 kHz cutoffs that were used in the experiments; in fact the authors continually use the word "inaudible" to describe such energy. They ran EEGs and PET scans which did seem to show significant neurological responses, but not auditory ones, and the authors were at a complete loss to explain the effect. No one has come up with any explanation since then, either. (Nor to my knowledge have any results such as this been duplicated by any other experimenters.)

What is most notable to me is what was not said, however. In published studies that are much more straightforward than this one, whenever you filter out the high frequencies from a recording using all-pass filters so as to control the phase below the cutoff point and keep it comparable for A versus B, you get a rapidly diminishing ability for listeners to determine whether the highs have been cut off or not as you get to about 12 kHz. By the time you raise the cutoff to 16 kHz there are very few people--including trained engineers and musicians--who can reliably tell you whether higher-frequency energy is present or not.

In this study, the participants listened to music that was filtered at 22 or 26 kHz--yet they readily assigned adjectives describing different sound quality to the "full-range sound" versus the "high-cut sound." This strongly suggests that the sound in the audible range wasn't the same, but I see no sign in the published report that the experimenters did anything to verify this one way or the other. And it's not that hard to do.

Enough is enough about this. I didn't volunteer to take on all comers; I'm just trying to say that if and when sampling rates above 44.1 kHz have any audible advantage, it's not because higher audio frequencies are being conveyed. There aren't any higher audio frequencies--because higher frequencies are not audio frequencies.

--best regards
« Last Edit: December 26, 2009, 06:53:43 PM by DSatz »
music > microphones > a recorder of some sort

Offline datbrad

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Re: Why record at 24/48 versus 24/44.1?
« Reply #34 on: August 04, 2009, 09:27:19 AM »
If you're into listening tests, perform the same procedures with your own gear but use audio instead of noise . . .

I don't know what relevance it has today, but I recall vividly back at the beginning of '90s when I first started using DAT recorders, I experimented with recording at 44.1 and also at 48, this at a time when the DAT tape was the only digital medium to listen to since the CDR for economical consumer use was 7 years away at that point.

Many people, both tapers and audiophiles with so called "golded ears", as well as casual listeners, could hear the difference between 44.1 and 48 on my home system. I did both microphone and SBD recording experiments with one set of a concert made at 44.1, and the other at 48, and on playback the 48 typically seemed to have cleaner highs, more "open" at the top end, if that makes any sense.

I would say that from '93 on, I always ran 48 on DAT as a result of my own admittedly unscientific experiments.
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Offline boojum

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Re: Why record at 24/48 versus 24/44.1?
« Reply #35 on: August 04, 2009, 01:05:46 PM »
If you're into listening tests, perform the same procedures with your own gear but use audio instead of noise . . .

<snip>

Many people, both tapers and audiophiles with so called "golded ears", as well as casual listeners, could hear the difference between 44.1 and 48 on my home system. I did both microphone and SBD recording experiments with one set of a concert made at 44.1, and the other at 48, and on playback the 48 typically seemed to have cleaner highs, more "open" at the top end, if that makes any sense.

<snip>


Was that a double blind test?
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Offline datbrad

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Re: Why record at 24/48 versus 24/44.1?
« Reply #36 on: August 04, 2009, 03:34:21 PM »
If you're into listening tests, perform the same procedures with your own gear but use audio instead of noise . . .

<snip>

Many people, both tapers and audiophiles with so called "golded ears", as well as casual listeners, could hear the difference between 44.1 and 48 on my home system. I did both microphone and SBD recording experiments with one set of a concert made at 44.1, and the other at 48, and on playback the 48 typically seemed to have cleaner highs, more "open" at the top end, if that makes any sense.

<snip>


Was that a double blind test?

No, it was only a single blind test. I knew which sources were which when I played them, only the people listening did not know there was a difference in recording sampling rates between the samples played back to them, or what difference they were asked to listen for. Some folks did not hear a difference, but most did, and only then did I tell them what the deal was.
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Offline boojum

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Re: Why record at 24/48 versus 24/44.1?
« Reply #37 on: August 04, 2009, 05:51:55 PM »
I am not arguing that your upgraded converters were not better, but I am always impressed with how much more often the proposition is proven rather than disproven in non double blind tests.  It seems to demonstrate that bias has a way of creeping in whether or not we believe it does.  For that reason I will always remain skeptical of non double blind tests.

I believe that people who test and want unbiased results use double blind tests to insure that the results are unbiased.  Double blind removes all doubt.    8)
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Offline Will_S

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Re: Why record at 24/48 versus 24/44.1?
« Reply #38 on: August 06, 2009, 08:51:26 AM »
Well in my case the only bias was the name I gave the files; "file1" and "file2".  Those names should have been selected by someone who didn't know which source file was which, but oh well.  Also, my test didn't prove that the new converter sounded better, just that it sounded different.

Well, no, that's the problem.  There may well have been an audible difference, but you told folks they were listening to two different sources and they "heard" a difference, some preferring one and some the other.  You likely would have gotten a similar result if you posted two copies of the same file under different names, some people will always "hear" a difference.

 

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