There is an interesting discussion at the Harbeth User Group about audio memory and sound comparison. Alan Shaw, the designer of Harbeth speakers, provided some interesting perspective from the point of view of a speaker designer.A few interesting points were being raised. I am very interested to hear what you guys have to add about this interesting subject.
Please see www.aes.org/sections/pnw/ppt.htm for a slide deck somewhat on this subject. Look for "why do we hear what we hear".
This is all the result of personal experience and introspection, which I'm quite trained in - nevertheless highly subjective, so your results may vary.*In this context 100 ms can already be very long.
What Constitutes our Long Term Audio Memory?We do have certain memory of sound - for example we can very quickly recognize the sound of say a trumpet. I am interested to find out what that memory consists of. I would like to investigate this from the perspective the cognitive processes associated with sound stimuli. Consider the following:Music and the Human Brain[blockquote]Consider the perception of timbre, the attributes that distinguish a saxophone from a trumpet. When both are playing the same note A4 each instrument creates a fundamental tone at 440 Hz, and the same spectrum of harmonics at frequencies of 880, 1320, 1760 Hz and so on. The relative amplitudes of the harmonics, and their variations over time, are what give the instrument its characteristic sound. Nerves from the regions of the cochlea excited by these frequencies send signals to the brain, and presumably a brain module recognizes the different pitches, similar to the way we recognize different colors - although at this level the recognition is probably not conscious. Now what? How on earth does the brain disentangle the overlapping saxophone and trumpet harmonic series, and re-assemble them, so we hear two distinct instruments, each playing a single note, rather than a mishmash of pitches? Levitin suggests that a difference of a few milliseconds in time between the arrival of the two harmonic series is the basis for this amazing feat. Directional clues might be used as well. I also suspect that our memory of what each of these instruments sounds like when played solo helps in this process, . The brain module that does this will even fix the bass response of a inferior stereo system. If an instrument plays a note that produces tones at 39, 78, 117, 156 Hz and so on, but your stereo system can't produce a 39 Hz tone, your brain will fill in the gap and you will hear a 39 Hz pitch! This phenomenon is called "restoration of the missing fundamental." All of this processing occurs automatically, largely in parallel, and without any conscious effort.Different pitches heard at the same time are processed by a module that extracts harmony. Different pitches heard at different times are processed by another module that extracts melody. Again we know this because Sacks describes patients who have lost one capability without affecting the other. Sacks describes a gifted musician who had a stroke. Suddenly he was unable to recognize a tune as simple as "happy birthday." Yet his perception of pitch and rhythm was intact, and he could read music and hum a melody. So the problem was specifically an inability of auditory processing of a sequence of pitches. [/blockquote]My conjecture is that the human brain do not store the actual sound of the various instruments - but only the interpretive modules that recognize the various sound.
I stand here watching people struggle with what is known as if it was not known. I guess we need something like "This Is Your Brain On Music" for dummies. All of the above conjectures and far more are answered in that book with tons of references to technical papers.
Quote from: Arnold B. Krueger on 28 May, 2010, 08:23:19 AMI stand here watching people struggle with what is known as if it was not known. I guess we need something like "This Is Your Brain On Music" for dummies. All of the above conjectures and far more are answered in that book with tons of references to technical papers.You mean to book Musicopilia?