In accordance with Fourier analysis, the leading edge gradient of a transient sound reproduced by a loudspeaker is defined by the high frequency response limit of the system; it is reproduced by the HF, not the LF driver. Given that our hearing deteriorates with age, this could be viewed as applying a low-pass filter gradually reducing perceived HF content as we age, and thus, theoretically, the leading edge gradient of a transient as perceived. (Considering a square wave signal, lowering the filter cutoff would eventually leave us with only the fundamental sine wave).
Imagine a listener who is unable to hear above a 5kHz pure tone and we play an unfiltered piece of music to them. Would this subjectively sound identical to the listener compared with the same piece of music having a 5kHz low pass filter applied, with particular regard to the perception of transient sounds? Phrased another way are we able to discern the difference between being unable to hear above a particular frequency compared with the absence of that HF information in the source, again considering only the perception of transients?
Imagine a listener who is unable to hear above a 5kHz pure tone and we play an unfiltered piece of music to them. Would this subjectively sound identical to the listener compared with the same piece of music having a 5kHz low pass filter applied, with particular regard to the perception of transient sounds? Phrased another way are we able to discern the difference between being unable to hear above a particular frequency compared with the absence of that HF information in the source, again considering only the perception of transients?
There is some reason to suspect that the brain learns to compensate to a degree for age-related hearing loss. One may not be able to hear HF like a teenager but it might be possible for the brain to learn how phase shifts at audible frequencies may imply something about likely properties of inaudible HF sound. IIUC there have been some recording and mastering engineers who were still able to make great sounding records despite some HF loss. Don't know if it has been studied exactly.
Regarding Fourier analysis, for it to hold true the system under consideration must be linear and time-invariant, or at least no more than weakly deviating from those things. Most of the more recent research on human hearing seems to be in the field of "Auditory Scene Analysis." Might be worth taking a look and see what you think about it. IMHO there will probably need to be some updates and revisions to the old psychoacoustic research audio engineers have be reading for a long time.
Regarding Fourier analysis, for it to hold true the system under consideration must be linear and time-invariant, or at least no more than weakly deviating from those things. Most of the more recent research on human hearing seems to be in the field of "Auditory Scene Analysis." Might be worth taking a look and see what you think about it. IMHO there will probably need to be some updates and revisions to the old psychoacoustic research audio engineers have be reading for a long time.
Many thanks - that has been a most valuable search term and a subject of which I was not aware. Good call! It's amazing to me how under-researched the subject of psychoacoustics remains on audio forums...
Presbycusis (age related hearing loss) is typically similar to a low order low pass filter followed by high order filter.
Suffering both from NIHL (noise induced hearing loss) centered at 4kHz and presbycusis, my hearing response could be looked at as similar to a 3.5kHz 48dB crossover with the HF (high frequency) turned down around 60dB.
Until the HF level reaches around 60dB, music subjectively sounds identical whether or not a 5kHz low pass filter was applied to it. Once the HF level exceeds around 60dB, I’d miss the HF content cut by the filter.
Presently, can’t hear above 14kHz at any level I’d consider safe for the rest of my hearing, so a steep filter down to 14kHz would not be detectable. Considering my genetics and present rate of presbycusis advancement, a 5kHz ceiling may happen before I die 💩.
At least my back hasn't given out 😉
Art
I have my doubts about the inevitability of age related HF hearing l loss. My hearing was damaged in 1969 by a howitzer @ ROTC camp. Instant tinitis. I've worn ear plugs ever since in loud situations, as at work in factories or mowing the lawn. My hearing was tested to 14 khz in 2008, and doesn't seem any different now 14 years later. I suspect a lot of "age related" hearing loss is men failing to protect their ears while using gas engines, fireworks, firearms, playing the music too loud, whatever. Earplugs are $1 a pair and worth the money to people that enjoy music as much as I do. At infrequent rock concerts I wear the plugs, and find the music more enjoyable without the buzzing of intermodulation distortion of the broken cilia. Pipe organ concerts too, if the trumpet pipes are really loud in a masonry wall building.
Presbycusis is inevitable, it's just whether you individually are ahead or behind the curve, and the rate of deterioration that differs.
My partner's hearing is better than a typical 30 year old female, while mine is more like an 80 year old, and we are both 65.
Together, we average out 🙂
Art
IIRC David Weems mentions a (Geometric mean?) in balancing of system frequency response, viz. the typical 20Hz - 20kHz stated human hearing response yields 400,000 (20 x 20k), presumably centred Geometrically around 1kHz. A POTS phone line yields 300Hz - 3.4kHz (1,020,000), the higher number leaning towards treble and sounding "tinny" to the ear.
Not sure if this aids the discussion, but the presence of low frequency harmonics may play a part in perception.
Have no fear, as Dr Smith would say:
Although young humans with normal hearing can hear sounds with frequencies between ∼20 and 20,000 Hz, only repetition rates between ∼30 and 4000 Hz elicit a pitch sensation that is salient enough to carry melodic information (Attneave and Olson, 1971; Pressnitzer et al., 2001).
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3481156/
Although young humans with normal hearing can hear sounds with frequencies between ∼20 and 20,000 Hz, only repetition rates between ∼30 and 4000 Hz elicit a pitch sensation that is salient enough to carry melodic information (Attneave and Olson, 1971; Pressnitzer et al., 2001).
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3481156/