Sound

Digital Delay For Application in Surround Sound

4.0 Results

4.2 SUBJECTIVE PSYCHOACOUSTIC TESTING

In total 14 people took the test, all of them male. Each declared that they could hear equally well in both ears, to the best of their knowledge. All of the test subjects had a strong background in acoustics.

A delay setting of 26 ms was used, which seemed appropriate for the environment.

NOTE: All tabulated values represent the percentage of the TOTAL number of people.

4.2.1 First Piece

The pre-determined piece which was played to the subjects was "Little Fluffy Clouds" by The Orb.

All of the test subjects liked the effect when played in surround sound.

TABLE 4.2 shows which boxes were ticked to best describe the effect when the music was played in surround sound.

 

MORE SPACIAL	ENGULFING	CONCERT HALL	DRAMATIC
46 %	46 %	0 %	4 %

TABLE 4.2 "Little Fluffy Clouds"

NOTE: In some cases subjects ticked two boxes as opposed to just one to describe the effect, this is represented by a half person for each appropriate box (3.5 %).

4.2.2 Second Piece

TABLE 4.3 Chosen Music

When asked to describe the type of material that the subject had chosen to listen to 14 % could not categorise their music using the categories provided, but essentially 7 % could be included in the rock group section, and the other 7 % in the electronic group.

TABLE 4.4 shows which boxes were ticked to best describe the effect, again in terms of percentage of the total number of people.

 

	CLASSICAL	ROCK	ELECTRONIC
MORE SPACIAL	0 %	14 %	21 %
ENGULFING	0 %	14 %	14 %
CONCERT HALL	0 %	7 %	0 %
DRAMATIC	0 %	0 %	7 %

TABLE 4.4 Chosen Music Effect

For the ROCK music, and of the 42 % of the subjects, 7 % did not like the effect and explained by saying that it was overpowering.

For the CLASSICAL music both subjects (14 %) did not tick any of the descriptive boxes.

One said that they did not notice much surround effect, where as the other felt it brings the music closer to the listener.

4.2.3 Comparisons With Other Systems

64 % had heard other types of surround systems, including ones not mentioned in the introduction (section 1.0). There appears to be some general confusion when referring to surround sound, as systems which utilise stereo widening techniques were sometimes thought of as been surround sound systems by some subjects.

TABLE 4.5 is the response to the question of how the system under test compared to other systems.

 

BETTER	EQUIVALENT	WORSE
21 %	29 %	0 %

TABLE 4.5 Comparison With Other Systems

One person failed to answer this section, and the other did not tick a box, preferring to say that the system was not as dramatic as Q sound recorded material listened to in normal stereo.

4.2.4 Commercial Viability

79 % considered the addition of a processor such as this to their present, or future hi-fi, worthwhile.
7 % person already had a commercially available surround sound processor.
14 % people did not consider the addition of such a processor worthwhile. One reason cited was that of the cost involved in purchasing extra speakers.

4.2.5 General Comments

1) A small number of subjects found that high frequencies from sources such as hi-hats in the rear speakers displeasing.

2) One subject felt that the effect was so inspiring that given the opportunity to mix recorded material he would give consideration to utilising out of phase information for the surround sound effect.

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