|
Posts: 253
Joined: August 21, 2012
|
Why Us compressed digital sound so annoying
50 years ago, music still had a bounce sound. Today, digital sound is compressed so much that it overwhelmed
the brain. Thus MP3 music and mobile phone calls are annoying.
By Thomas youth
Underground music quality?
Researchers are now looking into the brain to maximize the enjoyment of digital music
Until ten minutes running the conference call with colleagues from overseas, quite a few participants are
distracted and show signs of fatigue. Studies show that this often is due to the poor sound quality.
Are sounds affected, which has a measurable effect on the brain - even if we do not perceive the transfer
subjectively disturbed.
Researchers at the Technical University of Berlin to Benjamin Blankertz have examined how people respond
to gaps in the transmission or audio signals in low quality. You have test persons words and whole sentences
played that were transferred times the highest possible sound quality , sometimes in poor quality,
disturbed by background noise or by compression. This is common in digital music or transfer of mobile calls .
"Even if the subjects subjectively could make no difference between the original and the disturbed signal .
's Brain was still different activities the stronger the interference was pronounced ,
the more these activations were " Jan- Niklas Antons , researcher says at the TU Berlin.
The process thus seems to play on pre-conscious level. The effects can be directly observed in the brain :
In bad tone auditory areas are not just like when listening usual right and left active,
but also almost all of the central areas .
Fast tired, more stress
The synapses in the brain unconsciously activated fire it more often than would the sounds arrive at the
high quality head.
"This leads to a decreased attention , lets the recipient can ermüdenund faster also lead to stress," says Anton .
Is about the bad phone connection to a call center , the staff will tire quickly subside his attention quickly .
If the poor sound consciously perceived , should the caller show a reaction and join the conversation with
negative emotions.
Captures the recipient namely the interference of a transmission , and the frontal area of his brain with emotional
and cognitive processing is active. Even the Berlin researchers have studied .
" This so-called text -to-speech software has been used , the texts written automatically translated into language
and she reads . The poorer the quality , the more negative the subject rated the situation emotionally ," says Anton .
But it always depends on the context. Who, instead of two hours with colleagues via video conference to discuss a faulty line , chatting an equally long time with inferior sound quality with friends, is thus significantly less stressed .
Brain has to work more
In unconscious as conscious perception of poor sound quality so the brain is particularly active. But why? "
In the brain, on the signal is analyzed , and there will tapped cognitive contexts. It needs more work , therefore, if ,
for example, the caller difficult to understand. Too, it tries gaps created by disturbances or compression of the
audio signal to close. invoked the duration and leads to fatigue , "says Anton .
The results can be "probably transmitted to the listening to music ," says Anthony, "who exposes himself long
time digital , highly compressed music , for example in mp3 low bit rate , is also likely to become tired and
emotionally react negatively . "
Could so tiring two hours listening to mp3 music motorists faster? Basically, this is not ruled out ,
Anton wants so far but do not go . Other factors , such as the monotony while driving, likely in his opinion,
have a greater impact .
Subconscious mind hears with
Nevertheless, the effects of lack of sound quality when listening to music are of interest : first,
music recordings are often packaged as a digital MP3 file before , on the other hand they are already taken losses.
Compression works by sounds that have no influence on the perception of the listener away.
Awareness is difficult to discern a difference. But the subconscious is not fooled , the brain still tries permanently
to close the gaps.
"Besides music recordings are basically compact, the dynamic range has been reduced considerably .
Thereby, the volume level has shifted markedly upwards ," says Rolf Schmitz, Dolby ,
was responsible for the mobile business. Nuances are covered , thinned out the sound.
This brings the brain to be activated , which leads to fatigue.
End came with transistor radio
In the 50s music still had a bounce sound , already playing on transistor radios but has flattened him.
Taken to the extreme it is streaming to smartphones not only provide the built-in boxes little power ,
also have audio files are compressed for transmission over the radio path even further.
That music is already tuned to the emergence , Schmitz does not believe , however : "Most of the top ten titles,
the beats and the voice dominate but that does not mean that composers in the music so that it particularly
suitable for playback on small . speakers is . "
Finally, should sound reasonably well not only on the cell phone music,
but also for high-quality audio systems in clubs, in the car or on headphones .
Apart from compressed and lossy sounds also solves Music from irritation in the brain that has emerged on the synthesizer or computer. This results in a study by Professor Theo Geisel found at the Max Planck Institute for
Dynamics and Self-Organization . "The special thing of electronically created or post-processed music is that it is possible beats set extremely smoothly and precisely . And they can be positioned on a place in the music piece
exact and at will" , explains Holger Hennig, who was involved in the study and now as physicists at
Harvard University operates. However, such precision is anything but natural " .
A professional percussionist soaked in his punches - measured at a given by a metronome -
ten to 20 milliseconds from the time he is a little faster, sometimes a little slower ," said Hennig .
Randomly interspersed deviations
" The instruments , much has happened . Synthesizer can sound very natural , and drum machines form the
naturally occurring variations in the beats quite well after ," said Schmitz from Dolby .
However, scatters the software is usually a random deviations .
That does not help much , since the natural variations are not randomly distributed, but follow a pattern .
" The temporal shifts form self-similar structures : . . ,
The pattern in a particular played sequence is very similar to the pattern over the entire season Such fractals ,
there are often also found in nature , the section of a Farnblatts about looks similar to the whole fern leaf "
says Hennig .
Only when a software follows this pattern , the music comes the recipients good. "
In a test have volunteers pieces of music , in which a software deviations from the regular clock distributed
purely accidental evaluated as worse. Such purely random distribution is implemented in many softwares.
The jerky then very and sounds quite bumpy ," said Hennig, " humanized electronic music ,
in which our software the deviations has controlled for a natural pattern ,
on the other hand rated significantly better. "
The program could make it sound natural subsequently as an MP3 music stored .
Lossless Music for consumers
This also shows that the brain is particularly active in bad humanized music, especially the limbic system ,
are processed in the feelings. Ask experts in music production states that a person responsible for the
compression software the recipient do not like , it is not used " .
Such codecs undergone very extensive listening tests and analyzes.
The ultimate test is the listening experience of the consumer, and that has to be right," says Schmitz .
Consumers also can do a lot for it and dispense about to MP3 music. Amazon's Cloud Player ,
iTunes and many special services such as Linn Records , 2L , Naim and HIGHRESAUDIO offer virtually
loss-free music to download.
The resolution of these files , the gradation of the digital storage of sounds is 24 bit and are often higher than CDs.
And the sampling frequency , the number of times the signal is sampled ,
with 96 or even reaches 192 kilohertz peaks . This man can perceive only 16 kilohertz - at least consciously .
Perhaps the brain works still quite unconsciously more to fill the gaps in the scan.
The researchers want to find out in further studies.
Subject of the research is also the subject of " habituation " .
Scientists want to find out if people can get used to inferior sound quality.
When it comes to conscious awareness , it has already been proven ,
but it could possibly also apply unconscious Rezipieren .
Some researchers suggest that the brains of people who hear already as a teenager only MP3 music,
later do not want to fill the gaps in the compressed sounds and remain completely untouched by poor quality.
|
