Top Octave
default -- Wed, 02/11/2009 - 07:42
Dear Jonathon and others
I really seek clarification of what is meant
JV in a blog on the Soulution 710 amplifier in December described the inadequacies of digital reproduction by CD format, as being in the top octave, and several others wrote back they agreed with this assessment,
However i seek, for my own understanding what they are actually perceptually referring to
Is it the top octave of written music 4186 hz, the top octave of musical instruments c9 to g9 fundamental pitch, or the top octave of hearing c10 (16khz) and beyond
I certainly agree that there is a problem with traditional digital and the top musical octave(4khz), and secondly or instruments with spectra above 20 khz, ie: cymbals, percussion brass and others of these genres, as clearly 22.5 khz reproduction cuts these spectra off
However I think we need to be careful in the use of 'octave" in our descriptions, and frequency ranges, are far less ambigious
Interested in your feedback
Andrew
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I think of the top octave as 10kHz to 20kHz.
How many reviewers over the age of 40 have hearing that extends out beyond 13-15khz? Can Stevie, Robby or Jonnie hear 13khz? How's about 16khz? Doubtful? 20khz not a chance.
But they dont have balls to go get a hearing test to prove me wrong? All audio reviewers over the age of 35 shoudl be required to get semi annual hearing tests and once they are eligible for AARP like I will be in May then every year. What are you lads afraid of? You need to confront you fears and man up and admit boys you are getting old. So put on your Depends and get your hearing tested.
It would be interesting for JV and a reviewer in his middle twenties to compare notes.
And yes I specifically am being sexist since women's hearing is different than a males. Typically they hear higher frequencies etc.
Sheepherder
Shenandoah Valley, VA
Your question may be interesting, but as with many things in audio we have to think about this a bit.
There a significant thought in audio and auditory circles that we can hear well above 20khz. To understand the logic, it helps to understand that the majority of the ear's cell are not devoted to frequency detection. One of the functions of these non-frequency-oriented cells is to analyze the timing of incoming signals. In may (perhaps too) simple understanding of this, we may be able to detect upper frequencies through our ability to detect and analyze impluse signals (a lot of what is in real music).
Hearing tests use steady state signals (non-impulse). This may be why it is commonly said that we can't hear above 20khz when in fact it appears that we can, just not through direct frequency analysis. This is why supertweeters may work. It is also why high-bandwidth amps may sound better in the bass.
CEO and Editorial Director, Nextscreen LLC
The ability to hear above 15kHz is not a requirement for reaching accurate judgments about the quality of reproduced sound. Just listen to one of William Z. Johnson's latest designs (Audio Research) or a Keith Johnson recording. Both men are more than 20 years older than I am.
Messers Johnson have staffs which I am sure are not all members of AARP and collecting SS at the mandatory age. its a lame argument sir. What do you have to hide! if you can't hear the frequencies you raving about in the review of the BS amp and preamp or the Craptastic Model 666 speakers which cost $250k than your judgments are in question.
It would be like have doing reviews of Blu Ray and displays if you were color blind and could not see red or green.
I am sure you could get with a major university and have both pulsed, steady state and use real music etc for the hearing tests.
As a veteran I have copies of all my hearing tests since i entered service as OCS candidate and my VA hearing tests too. You and your review staff need to one read the current literature on hearing and age and get your hearing tested.
Sheepherder
Shenandoah Valley, VA
Sheepherder -- there's nothing to hide. There's close to 100% certainty that the older members of the staff have worse high frequency sine wave sensitivity than the middle-aged members, and that middle-aged staffers have worse hf sensitivity than younger members. But we should think about what this means.
Music is not primarily composed of sine waves, and the ear is not primarily set up to detect them -- so what does sine wave sensitivity mean for the ability to hear music?
Does experience in detecting phenomena matter, particularly if artifacts of those phenomena exist in the time domain?
Do we know how time domain sensitivity changes with age?
Most of our readers are middle-aged, so what is the best approach for them?
Pearson, Harley, Valin et al continue to make useful observations that others can readily verify (or not, depending on your interests and skills), so users can choose to focus on that or on a theory that a test (or biology) renders certain judgements questionable as they wish.
CEO and Editorial Director, Nextscreen LLC
For what it's worth, the last time I had my hearing checked, which was about a year ago, I was still hearing out to 16kHz, according to the audiologist. Put that in your ear trumpet and smoke it.
I think we know the following, based on science.
1. There is considerable dynamic energy produced by musical instruments above the 20kHz "threshold" of hearing. E.g., 40% of the acoustic energy generated by a cymbal crash is measurable above 20 kHz and measurable amounts occur as high as 102 kHz
2,. The determination of the 20 to 20 audible range is based on measuring the response of the ear drum (albeit of young healthy listeners) and not the brain.
3. Brain scan studies based on both electrical brain activity images and blood flow through the brain stem suggest that the brain does behave differently when music in the audible 20 - 20 band is augmented by HF extension well above the 20 kHz threshold.
4. Science has not established the receptor mechanisms of the body that pick up the ultra high frequency information; could it be the skeletal system, or the skin? (I am encouraging young neuroscience students to study this phenomenon and advance the3 science on this topic.
5. This helps to explain a the seemingly counter intuitive observation of many a listener, yours truly included, that observe the impact of super tweeters on bass and (more correctly dynamic resolution.)
Fascinating stuff......
-Atul
Quick add:
Interestingly there is very little harmonic energy measurable above 20KHz. Transient energy is the larger effect.