What Do We Mean By Audible - A Slide Show - AVS Forum
Forum Jump: 
 
Thread Tools
post #1 of 24 Old 06-27-2007, 03:21 PM - Thread Starter
AVS Addicted Member
 
Chu Gai's Avatar
 
Join Date: Sep 2002
Location: NYC area
Posts: 14,964
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 317 Post(s)
Liked: 595
Click here.

"I've found that when you want to know the truth about someone that someone is probably the last person you should ask." - Gregory House
Chu Gai is online now  
Sponsored Links
Advertisement
 
post #2 of 24 Old 06-27-2007, 05:58 PM
 
ChrisWiggles's Avatar
 
Join Date: Nov 2002
Location: Seattle
Posts: 20,730
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 15
WHAT????

SPEAK UP!!!



No, but that was an interesting slideshow, I hope people go through it.

One serious criticism though, is that the trial being discussed has to do with volume change, and then there is the bullet point which states:

"In the case of 20-bit vs 24 bit, the actual change in voltage is less than 1/10,000th of 1%"

...which insinuates that such a difference is not audible, but that does not relate to the question being tested which is differentiating volume.
ChrisWiggles is offline  
post #3 of 24 Old 06-27-2007, 06:18 PM
AVS Special Member
 
JorgeLopez11's Avatar
 
Join Date: Oct 2003
Location: MEXICO CITY
Posts: 1,890
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 18
Interesting.

I remember that 0.3dB is the figure used for definitive discriminatory tests.... so I wonder why the autor used 0.4 dB instead.
JorgeLopez11 is offline  
post #4 of 24 Old 06-27-2007, 07:30 PM
AVS Addicted Member
 
Kal Rubinson's Avatar
 
Join Date: Mar 2004
Location: NYC + Connecticut
Posts: 28,490
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 97 Post(s)
Liked: 142
Quote:
Originally Posted by ChrisWiggles View Post

One serious criticism though, is that the trial being discussed has to do with volume change, and then there is the bullet point which states:

"In the case of 20-bit vs 24 bit, the actual change in voltage is less than 1/10,000th of 1%"

...which insinuates that such a difference is not audible, but that does not relate to the question being tested which is differentiating volume.

Yeah. That sorta stuck out like a sore thumb to me, too.

Kal Rubinson

"Music in the Round"
Senior Contributing Editor, Stereophile
http://www.stereophile.com/category/music-round

Kal Rubinson is offline  
post #5 of 24 Old 06-27-2007, 09:23 PM
Senior Member
 
ross's Avatar
 
Join Date: Dec 1999
Location: Vista California
Posts: 264
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Since the statistical data in his small experiment get down to an almost random point, I don't see that it would be affected much by .3db versus .4. You're already at an "almost" random result and need more people and trials. Pls comment?

I was confused by this comment: "In the case of 20-bit vs 24 bit, the actual change in voltage is less than 1/10,000th of 1%"

...which insinuates that such a difference is not audible, but that does not relate to the question being tested which is differentiating volume."

I would have thought that if you are an order of magnitude or two beyond the .4db that expecting that diff to be audible is awfully unlikely. So, it's more than an insinuation. What am I missing?

Rgrds-Ross
ross is offline  
post #6 of 24 Old 06-27-2007, 10:01 PM
Advanced Member
 
Harrypt's Avatar
 
Join Date: Dec 2006
Posts: 766
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Wouldn't it be more interesting to say, oh... set up some tests and do some listening experiments instead of just combing the web for random things other people have written to strengthen your argument?
Harrypt is offline  
post #7 of 24 Old 06-27-2007, 10:16 PM - Thread Starter
AVS Addicted Member
 
Chu Gai's Avatar
 
Join Date: Sep 2002
Location: NYC area
Posts: 14,964
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 317 Post(s)
Liked: 595
Probably used 0.4 dB because of the specific population that he tested. A larger population that perhaps encompassed younger trained people might've eeked that down a bit.

With regards to Chris' comments, I've sent an email over to the author for clarification. I think? he was looking at it from the least signficant bit in those systems.

You could Harrypt, but the wheel doesn't have to be continuously reinvented.

"I've found that when you want to know the truth about someone that someone is probably the last person you should ask." - Gregory House
Chu Gai is online now  
post #8 of 24 Old 06-28-2007, 09:40 PM
AVS Special Member
 
speco2003's Avatar
 
Join Date: Aug 2003
Location: Las Vegas NV
Posts: 2,349
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 20
Most of that is old news just presented better for the masses. Too bad most if not all snake oil lovers still wont get it. Oh well a fool and his money......
speco2003 is offline  
post #9 of 24 Old 06-29-2007, 08:45 AM
AVS Special Member
 
ssteel01's Avatar
 
Join Date: Jul 2003
Location: Boston Area, MA
Posts: 1,243
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by Chu Gai View Post

Click here.

So....what you're saying is that level matching isn't all that important when comparing components? Hehehehehehe...


Scott
ssteel01 is offline  
post #10 of 24 Old 06-29-2007, 09:15 AM
AVS Special Member
 
JorgeLopez11's Avatar
 
Join Date: Oct 2003
Location: MEXICO CITY
Posts: 1,890
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 18
On the contrary. Level matching is absolutely mandatory in audio subjective tests because most audio qualities are dependent on sound intensity. People tend to choose the audio equipment/device whose volume is higher,
JorgeLopez11 is offline  
post #11 of 24 Old 06-29-2007, 09:23 AM
AVS Special Member
 
Randybes's Avatar
 
Join Date: May 2002
Location: Midwest
Posts: 2,622
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 12
Quote:
Originally Posted by JorgeLopez11 View Post

On the contrary. Level matching is absolutely mandatory in audio subjective tests because most audio qualities are dependent on sound intensity. People tend to choose the audio equipment/device whose volume is higher,

So if you want a better system, just turn up the volume
Randybes is offline  
post #12 of 24 Old 06-29-2007, 11:40 AM
AVS Special Member
 
Ethan Winer's Avatar
 
Join Date: Apr 2003
Location: New Milford, CT, USA
Posts: 5,748
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Liked: 134
Quote:
Originally Posted by Chu Gai View Post

What Do We Mean By Audible

One thing I've noticed that has a large bearing on our ability to distinguish small changes in volume and tonality is listening in an environment that is free of all early reflections. I've been a professional audio engineer for most of my adult life, and I remember clearly the first time I did a mix after treating all the first reflection points in my studio. All of a sudden I could hear very small changes - definitely less than 0.4 dB - very clearly. Not only changes in volume, but in EQ and effects such as reverb too. I bet if that test were conducted in a reflection free zone (RFZ) that the results would be at least a little different, with more people able to notice finer detail.

--Ethan

RealTraps - The acoustic treatment experts
Ethan's Audio Expert book

Ethan Winer is offline  
post #13 of 24 Old 06-29-2007, 11:46 AM
AVS Special Member
 
scorch123's Avatar
 
Join Date: Jun 2004
Location: Chandler, AZ
Posts: 1,824
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
That was an interesting presentation. It would be useful to see the data behind the conclusions and analysis.

The sample size of n=30 stuck out to me.

From the tests and the data, I honestly don't see how the 3rd conclusion was made:

"Audibility is a psychological phenomenon as much or more than a physical one."

A good test for that would have been A & B being exactly the same loudness. How many of the 30 would have answered yes or no? Truly that would help hypothesis test whether loudness is psychological and/or physical.

This definitely got me thinking about something different this morning

- Steve O.
scorch123 is offline  
post #14 of 24 Old 06-29-2007, 11:51 AM - Thread Starter
AVS Addicted Member
 
Chu Gai's Avatar
 
Join Date: Sep 2002
Location: NYC area
Posts: 14,964
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 317 Post(s)
Liked: 595
Quote:


So....what you're saying is that level matching isn't all that important when comparing components? Hehehehehehe...


Scott

Exactly Scott! It's important to just play them the way you want, listen to what the salesman says, focus intensely where he wants you to focus, and above all realize that using the right wires, elevation cones or different blocks of wood, replacing good resistors and capacitors with more expensive audiophile versions, is the clue.

Ethan, what do you think of Moulton's comments regarding reflections when it comes to speaker designs?

"I've found that when you want to know the truth about someone that someone is probably the last person you should ask." - Gregory House
Chu Gai is online now  
post #15 of 24 Old 06-29-2007, 12:18 PM
AVS Special Member
 
ssteel01's Avatar
 
Join Date: Jul 2003
Location: Boston Area, MA
Posts: 1,243
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by Chu Gai View Post

Exactly Scott! It's important to just play them the way you want, listen to what the salesman says, focus intensely where he wants you to focus, and above all realize that using the right wires, elevation cones or different blocks of wood, replacing good resistors and capacitors with more expensive audiophile versions, is the clue.

That's just crazy talk. Besides, everyone knows audio nirvana is all about using the right light switch covers.

But seriously (and just for the record) I do appreciate the need for level matching, but I do find it interesting that the stringency you can achieve may be in excess of what is audible. Also, as Steve O. pointed out, I always think it would be informative to see control data for these sorts of studies to see what the rates of false postives/negatives are.


Scott
ssteel01 is offline  
post #16 of 24 Old 06-29-2007, 01:36 PM - Thread Starter
AVS Addicted Member
 
Chu Gai's Avatar
 
Join Date: Sep 2002
Location: NYC area
Posts: 14,964
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 317 Post(s)
Liked: 595
Maybe Steve O. will chime in with exactly what he's talking about and in what context.

I think machinadynamica was truly based on the premise of what kind of absolute ridiculousness and bull$hit can I tell and still sell something.

"I've found that when you want to know the truth about someone that someone is probably the last person you should ask." - Gregory House
Chu Gai is online now  
post #17 of 24 Old 06-29-2007, 02:03 PM
AVS Special Member
 
krabapple's Avatar
 
Join Date: Apr 2003
Location: in a state bordered by Kentucky and Maine
Posts: 5,360
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 177 Post(s)
Liked: 229
Quote:
Originally Posted by Harrypt View Post

Wouldn't it be more interesting to say, oh... set up some tests and do some listening experiments instead of just combing the web for random things other people have written to strengthen your argument?

Do you yourself typically repeat scientific experiments personally, before you accept their results?

In this case the data are saying that a 0.4 dB level difference is probably not audible (especially for musical samples). You have a problem with that? It's not some controversial new findings; it's quite in accord with previous studies of JNDs.
krabapple is online now  
post #18 of 24 Old 06-29-2007, 02:20 PM - Thread Starter
AVS Addicted Member
 
Chu Gai's Avatar
 
Join Date: Sep 2002
Location: NYC area
Posts: 14,964
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 317 Post(s)
Liked: 595
I made a right triangle with two of the sides being 3" and 4". Should I measure the hypotenuse or just calculate it?

"I've found that when you want to know the truth about someone that someone is probably the last person you should ask." - Gregory House
Chu Gai is online now  
post #19 of 24 Old 06-29-2007, 05:24 PM - Thread Starter
AVS Addicted Member
 
Chu Gai's Avatar
 
Join Date: Sep 2002
Location: NYC area
Posts: 14,964
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 317 Post(s)
Liked: 595
I asked,
Quote:


On slide 40 of 45 in "What do we mean by audibility" from the Parson's website, it is stated,

In the case of 20-bit vs. 24-bit, the actual change in voltage magnitude is less than 1/10,000th of 1%.

What do you mean by that?

He replied,
Quote:


Thanks for the question!

20 bit yields a ratio of approximately 1:1,000,000, while 24 bit yields a ratio of approximately 1:16,000,000. Assuming that the voltage ratios have a fixed and identical upper value of, say, 1, the 20 bit lower value will be 1:.000001, or 1/10,000th of 1 percent, while the 24 bit value will have a lower value of 1/16th of 1/10,000th of 1 percent, or, slightly less than 1/100,000th of 1 percent.

These are extremely small magnitudes and magnitude changes, and are essentially well below the noise floor of any reasonable audio signal. The actual CHANGE in magnitude will be from, say, 1 millionth of a volt to 1/16 millionth of a volt. Viewed as a percentage change, this will be, by definition, less than the % of signal that the 20 bit signal represents, which is, once again, 1/10,000th of 1%.

This all works out this way because we tie everything to a maximum level of 0 dBFS. All changes in magnitude ratios happen at the vanishingly small end of the range.

I hope this helps. If not, give me a call.

Thanks for writing.

Best,

Dave Moulton


"I've found that when you want to know the truth about someone that someone is probably the last person you should ask." - Gregory House
Chu Gai is online now  
post #20 of 24 Old 06-29-2007, 07:59 PM
Advanced Member
 
Harrypt's Avatar
 
Join Date: Dec 2006
Posts: 766
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by krabapple View Post

Do you yourself typically repeat scientific experiments personally, before you accept their results?

In this case the data are saying that a 0.4 dB level difference is probably not audible (especially for musical samples). You have a problem with that? It's not some controversial new findings; it's quite in accord with previous studies of JNDs.

He found a PP presentation on the web and that is scientific proof to you? Laff.
Harrypt is offline  
post #21 of 24 Old 06-29-2007, 11:40 PM
AVS Special Member
 
krabapple's Avatar
 
Join Date: Apr 2003
Location: in a state bordered by Kentucky and Maine
Posts: 5,360
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 177 Post(s)
Liked: 229
And Chu performing and reporting his own test would be better 'proof' to you? Laff.

You're full of it. The real question for people like you is, what proof *would* you accept, that the current scientific consensus on JNDs is correct?
krabapple is online now  
post #22 of 24 Old 06-30-2007, 12:14 AM
Senior Member
 
allsop4now's Avatar
 
Join Date: Oct 2006
Posts: 354
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
People - "audiophiles" included - find it hard to accept scientific results that contradicts cherished beliefs, in particular unsubstantiated ones like astrology or religion.
allsop4now is offline  
post #23 of 24 Old 06-30-2007, 09:47 AM
AVS Special Member
 
Ethan Winer's Avatar
 
Join Date: Apr 2003
Location: New Milford, CT, USA
Posts: 5,748
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Liked: 134
Quote:
Originally Posted by Chu Gai View Post

Ethan, what do you think of Moulton's comments regarding reflections when it comes to speaker designs?

Got a link or quote?

RealTraps - The acoustic treatment experts
Ethan's Audio Expert book

Ethan Winer is offline  
post #24 of 24 Old 06-30-2007, 11:54 AM
Member
 
ImportSport's Avatar
 
Join Date: Feb 2007
Location: Nashville, TN
Posts: 37
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
There is a vast body of literature on speech and signal audibility. Our students have a semester long course on audibility theories and their reliability from a psychoacoustic perspective.

It's an extraordinarily complex topic. This presentation did a decent job of talking about JND but it really only pertains to a very small portion of audibility and how it interacts with perception.
ImportSport is offline  
Reply Audio Theory, Setup, and Chat

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off