Category Archives: Psychoacoustics

Testing Aural Perception through Audio Format: Results and Conclusions

Results:

Correct Source ID by Song Type

Source Preference by Music Type

Correct Source ID by Sex

Conclusions:

At the beginning of this investigation we sought to determine whether or not a person presented with two samples of music––one primarily acoustic and the other primarily electric, and each played in random order in vinyl and MP3 format––can accurately perceive differences in audio quality between music formats. Attempting to answer this question we tested ten male and ten female subjects, each of whom listened to samples of the Pixies’ “Where Is My Mind?” and New Order’s “Blue Monday.” Among the questions we considered during testing:

1) Might males and females demonstrate different preferences in audio format?

– Furthermore, would these differences be reflected when the genre of the music     changes?

2) Might males and females differ in accuracy regarding which source is which?

– As with Question 1, might these differences be reflected when the genre of the   music changes?

3) Might perceived higher quality in a particular genre of music be associated with either the LP (vinyl) or MP3 (computer) format?

Upon completion of our testing we disaggregated the data into the following categories and sub-categories:

# of people who determined the sound sources correctly for both songs: 7/20.

Of those:

Males: 4/7.

Females: 3/7.

# of people who determined the sound sources correctly for “What Is My Mind?”: 9/20.

Of those:

Males: 5/9.

Females: 4/9.

# of people who determined the sound sources correctly for “Blue Monday”: 14/20.

Of those:

Males: 8/14.

Females: 6/14.

# of people who preferred the LP for “Blue Monday”: 9/20.

Of those:

Males: 3/9.

Females: 6/9.

# of people who preferred the computer for “Blue Monday”: 10/20.

Of those:

Males: 7/10.

Females: 3/10 (One female was indecisive).

# of people who preferred the LP for “Where Is My Mind?”: 17/20

Of those:

Males: 8/17.

Females: 9/17.

# of people who preferred the computer for “Where Is My Mind?”: 3/20

Of those:

Males: 2/3.

Females: 1/3.

From this data we can arrive at the following conclusions:

In response to Question 1:

– Of those who preferred the LP with “Blue Monday,” the majority (6/9) were female. Of those who preferred the computer, the majority (7/10) were male.

– Of those who preferred the LP with “Where Is My Mind,” 9/17 were female. Of those who preferred the computer, 2/3 were male.

– For “Blue Monday,” we can see a clear pattern of males preferring a digital format, whereas females prefer an analog format. For “Where Is My Mind,” there is no decisive margin in either direction. This seems to suggest that, for electronic music, format differences trigger more divided reactions among males and females than with acoustic music.

In response to Questions 2 and 3:

– Of those who correctly determined which source was the computer with “Blue Monday,” only a slim majority were male (8/14). Of those who correctly determined which source was the computer with “Where Is My Mind,” the same was true (5/9). This data, given our small sample size, is inconclusive, but could simply be telling us that males and females are equally adept at perceiving differences in sound quality.

– Interestingly, 14 of the subjects were correct with “Blue Monday,” a 55.5% greater number than were correct for “Where Is My Mind?” The great difference in accuracy between the two songs is interesting when one considers that a very high 17/20 people preferred the LP for “Where Is My Mind?” while preferences were more split for “Blue Monday.” We believe this could reflect a bias among test subjects who believe higher quality in acoustic music such as “Where Is My Mind?” is linked to vinyl, while higher quality in electronic music such as “Blue Monday” is linked to MP3s. This potential bias is reflected in test subject comments about the particular qualities they noticed while listening. For example, “Blue Monday” as an MP3 was frequently cited for better and more distinct bass, while “Where Is My Mind?” as an LP was noted for clearer instrumentation.

– Ultimately it seems that, aside from a statistically significant difference in preferences of format for electronic music, there is little discernable difference in audio perception or preference between males and females. Most apparently, though, it seems that people generally have less than a random coin toss’ chance of guessing both sources in both audio samples correctly (7/20 managed to achieve this). People are more able to do so for electronic music than for acoustic music, but because of the way in which the potential bias toward a specific format for a specific genre may have colored people’s guesses, the electronic/acoustic distinction regarding accuracy is inconclusive. On the whole, however, it seems that the human ear picks up on relatively few differences in MP3s and LPs, formats of definitively varied quality.

Testing Aural Perception Through Audio Formats: Complete Raw Data

Raw Data:

Below are the questions each test subject answers upon hearing each audio sample, to which the numbered answers in each piece of data correspond.

1) If you had to say, without defining what quality means. Which Source is of higher quality?

2) Is there any characteristic of one source that you noted?

3) If you had to guess which source is the computer

SUBJECT 1:

Gender: Female

TEST1:

Where Is My Mind?

SOURCE1: LP

SOURCE2: COMPUTER

1) Second one = higher quality

2) The beginning sounded clearer over the second source.

3) The computer was the first one.

TEST2

Blue Monday

SOURCE1: LP

SOURCE2: COMPUTER

1) Cannot tell

2) The same

3) The second

SUBJECT 2

Gender: Female

TEST1

Blue Monday

SOURCE1: COMPUTER

SOURCE2: LP

1) The first one

2) Treble clearer in first one

3) The second

TEST2

Where is my mind

SOURCE1: LP

SOURCE2: COMPUTER

1) The first source

2) The bass was more pronounced in the second

3) The first source

*SUBJECT3

Gender: Male

TEST1

Where is my mind

SOURCE1: COMPUTER

SOURCE2: LP

1) Source one

2) The bass was cleaner in the first, electric guitar was more pronounced, percussion was clearer.

3) Number two

TEST2

Blue Monday

SOURCE1: LP

SOURCE2: COMPUTER

1) Source One

2) The second one sounded more crowded, louder, the percussion on the first one sounded deeper

3) Number two

*SUBJECT4

Gender: Male

TEST1

Blue monday

SOURCE1: LP

SOURCE2: COMPUTER

1) Source one

2) More range in source one, frequencies were more “there”, everything sounded similar in source one

3)Source two

TEST2

Where is my mind

SOURCE1: LP

SOURCE2: COMPUTER

1) Source one.

2) The vocals sounded better in source two, the beginning

3)Source two

SUBJECT5

Gender: Male

TEST1

Where is my mind

SOURCE1: LP

SOURCE2: COMPUTER

1) Source one

2) Second, bass and drums more prominent

3) Source 2

TEST2

Blue Monday

SOURCE1: COMPUTER

SOURCE2:LP

1) Source one

2) Second one was faster

3) Source one

SUBJECT6

Gender: Male

TEST1

Blue Monday

SOURCE1: LP

SOURCE2: COMPUTER

1) Source two

2) More bass in second

3) Source one

TEST2

Where is my mind

SOURCE1: COMPUTER

SOURCE2: LP

1) Source two

2) The bass was higher on second

3) Source one

SUBJECT-7

Gender: Male

TEST-1

Where is my mind

Source 1: Computer

Source 2: LP

1) Source two

2) The sound, especially bass felt more “real”

3) Source two

TEST-2

Blue Monday

Source 1: computer

Source 2: LP

1) Source two.

2) I don’t know why, just liked it better

3) Source two

SUBJECT-8

Gender: Female

TEST-1

Blue Monday

Source 1: Computer

Source 2: LP

1) Source 2

2) The percussion felt more intense in a good way

3) Source 2

TEST-2

Where is my mind

Source 1: LP

Source 2: computer

1) source 1

2) the guitar sounded more detailed, more prominent in the mix

3) source 2

SUBJECT-9

Gender: Male

TEST-1

Where is my mind

Source 1: LP

Source 2:  computer

1) Source 1

2) Sounded more like a live sound, reverb was better.

3) Source 2

TEST-2

Blue monday

Source 1: computer

Source 2: LP

1) Source 1

2) I preferred the rawer sound of source 2 but source one was better “quality”

3) source 1

SUBJECT-10

Gender: Male

TEST-1

Blue monday

Source 1: computer

Source 2: LP

1) Source 1

2) More bass frequency

3) Source 1

TEST-2

Where is my mind

Source 1: LP

Source 2: computer

1) Source 2

2) unsure

3) Source 2

SUBJECT-11

Gender: Female

TEST-1

Where is my mind

Source 1: LP

Source 2: computer

1) Source 1

2) The instruments sounded more distinct in the mix

3) Source 2

TEST-2

Blue monday

Source 1: LP

Source 2: computer

1) Source 1

2) I liked the synth sounds at the end better

3) Source 2

SUBJECT-12

Gender: Female

TEST-1

Blue monday

Source 1: computer

Source 2: LP

1) Source 2

2) The percussion was clearer

3) Source 2

TEST-2

Where is my mind

Source 1: computer

Source 2: LP

1) Source 2

2) it sounded more real

3) Source 2

SUBJECT-13

Gender: Male

TEST-1

Where is my mind

Source 1: computer

Source 2: LP

1) source 2

2) better blend of the parts

3) source 2

TEST-2

Blue monday

Source 1: LP

Source 2: Computer

1) source 2

2) The bass sounded better

3) source 2

SUBJECT-14

Gender: Female

TEST-1

Blue monday

Source 1: computer

Source 2: LP

1) Source 2

2) Sounded more interesting

3) Source 1

TEST-2

Where is my mind

Source 1: computer

Source 2: LP

1) source 2

2) Sounded very full in sound

3) source 1

SUBJECT-15

Gender: Female

TEST-1

Where is my mind

Source 1: computer

Source 2: LP

1) Source 2

2) sounded better mixed

3) source 2

TEST-2

Blue monday

Source 1: LP

Source 2: computer

1) Source 2

2) Much cleaner sound

3) source 2

SUBJECT-16

Gender: Male

TEST-1

Blue monday

Source 1: LP

Source 2: computer

1) Source 2

2) The difference between the highs and the lows was more apparent

3) Source 2

TEST-2

Where is my mind

Source 1: LP

Source 2: computer

1) Source 1

2) The guitar sounded more live

3) Source 1

SUBJECT-17

Gender: Female

TEST-1

Where is my mind

Source 1: computer

Source 2: LP

1) Source 2

2) Warmer sound, more like being in a nice venue

3) source 1

TEST-2

Blue monday

Source 1: LP

Source 2: computer

1) Source 1

2) more nuanced and interesting sound

3) source 2

SUBJECT-18

Gender: Male

TEST-1

Blue monday

Source 1: LP

Source 2: computer

1) Source 2

2) cleaner sound, sounded “bigger” more danceable

3) Source 2

TEST-2

Where is my mind

Source 1: computer

Source 2: LP

1) Source 2

2) same reason, bigger sound

3) source 2

SUBJECT-19

Gender: Female

TEST-1

Where is my mind

Source 1: computer

Source 2: LP

1) Source 2

2) nothing really that I can think of

3) source 2

TEST-2

Blue monday

Source 1: computer

Source 2: LP

1) Source 2

2) just liked it better, was definetly easier to differentiate than the first test.

3) source 2

SUBJECT-20

Gender: Female

TEST-1

Blue monday

Source 1: LP

Source 2: computer

1) source 2

2) the guitar and synth parts sounded cleaner in the mix

3) source 2

TEST-2

Where is my mind

Source 1: LP

Source 2:  computer

1) Source 1

2) The bass was more prominent in the mix and seemed more intense

3) source 1

Project Data (Round 1)

To test whether “average” music listeners can interpret a difference in sound quality or listening experience between songs played in digital (mp3) format and songs played in analog (vinyl) format, Group 10 planned an experiment that would require participants to listen to two 90-second samples of a primarily acoustic song (one played in mp3 format, and the other played in analog format).  The participant was blindfolded, and the order in which we played the analog and mp3 formats was determined by a coin-toss before each test.  After answering questions about the differences they noticed between the two copies of the same acoustic song, the experiment was repeated with a primarily electronic song.  We decided to use two songs from the acoustic and electronic genres primarily to see if there was any difference in format preference for either genre (for example, it has been argued that analog recordings better capture the range and depth of acoustic instruments, and that mp3s may be ideally suited to play computer-generated music).

The following questions were asked of participants after each of their two “tests”:

1)    Without defining the term, which sound source was of “higher quality”?

2)    Did you notice any memorable characteristics of either sound source?

3)    If you had to guess which sound source was played from a computer, which would you choose?

For our first round of data collection, we sampled six participants, four males and two females, all students at Vassar College and between the ages of 18 and 22.  *Please note that we plan to have sampled a total of twenty participants by next week.

At this first stage in our data gathering process, we cannot identify a significant difference in our data, and thus cannot conclusively state whether our hypothesis, that analog music will be interpreted by listeners as “higher quality”, cannot yet be confirmed.

Preferred Format by Music Type:

If anyone is interested, here are the links to the two songs we used!

Electronic: http://www.youtube.com/watch?v=VyoDbX1EkPQ

Acoustic: http://www.youtube.com/watch?v=RCD14IrOcIs

GROUP 10 PROJECT PLAN

Project Plan

Purpose:

Can the average consumer perceive the difference between high fidelity analog recording and compressed digital formats?

Hypothesis:

If we present a subject with a blind sample of the same audio recording on two different formats then it is assumed that they will be able to notice a difference and prefer the higher fidelity audio recording. The reason being that there is not the distortion caused by clipping when an analog source is converted to digital.

Materials:

-High-fidelity recording headphones

-Computer

-Quality analog recording (format: long playing record)

-Associated record player

-blindfold

-coin (for randomization)

Procedure:

-Acquire a sample pool of subjects, have a mix of age and gender.

-Induce the subject to be blindfolded

-flip the coin to decide if the MP3 format or the record will be played first.

-play the recordings back to back to the subject.

-Ask the subject which format A or B he/she preferred

-Ask the subject to guess which of the two recording was on the higher quality

-Repeat this process for all members of your subject pool.

-Compare the data

Hi-Fi in the Age of iTunes: Examining Audio Quality and Aural Perception

Confronted with a huge variety of digital and analog formats, and music coming from an increasingly diverse array of sources, it may be difficult for a consumer of music to accurately assess the quality of the product he/she is getting. But then the question arises: Can the human ear really tell the difference between digital and analog, and between different degrees of compression? What sorts of variations can the ear pick up in frequency ranges and distortion? By testing a broad range of subjects against sets of formats, samples of music, and compressions, we hope to learn just how discerning the human ear can be.

Welcome!

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Getting Started…

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