Re: Timing Comparison?

sheesh… typing corrections?? 

Within a critical band, you cannot separately distinguish the loudness of two nearby tones. Or rather, the loudness masking from the louder sound drowns out the presence of the lesser sound.

At any rate, a true-to-life correction system would need this kind of spectral fluidity. But for use in a realtime correction system, intended to help performers in live sessions, you can’t dilly-dally. You have to respond very quickly, on the order of 5 ms. And so you have to live with approximations.

Our loudness response is not nearly as critical as our pitch perception, and so approximations work well enough.

> On Nov 3, 2025, at 07:05, David McClain (as dbm at refined-audiometrics dot com) <[email protected]> wrote:
> 
> I would say a LPF is too crude. It is all sound level dependent. At low sound levels you do have a severe lowpass filter effect - my own are woofers with -24 dB/octave above 1 kHz. 
> 
> But at loud enough levels the curve flattens our to normalcy. 
> 
> So this makes the system a nonlinear compressor, in each Bark band.
> 
> Bark bands are really not fixed in frequency - they are self organizing around the loudest spectral peaks, and their bandwidth describes the critical bands of hearing. Within each critical band, you can separately discern the loudness difference between two nearby tones.
> 
> The nonlinear compression curves look a lot like the J of a ski-jump. They level out at low sound levels, and then rise steeply to become nearly normal at loud levels. Level-out means they must apply amplification in inverse proportion to the dB level of incoming sound. Steeping means they need to apply ever less amplification. At the very loudest levels, our hearing all converges to normal.
> 
> When you have Sensioneural impairment - as contrasted against a U-shaped hearing curve often seen among former Artillery Officers - then you have impairment at all frequencies and the degree of impairment is nearly a straight line in dB measure against Bark frequency. The variation from one person to the next is just the degree of impairment, but their line is parallel to those of other people in dB-Bark space.
> 
> 
>> On Nov 3, 2025, at 06:56, Yuri Davidovsky <[email protected]> wrote:
>> 
>> 
>> 
>>> On 3 Nov 2025, at 14:40, David McClain <[email protected]> wrote:
>>> 
>>> What we found is that all humans have impairment slopes that average around 3.2 dB/Bark. What varies is the degree of impairment, but not its spectral slope.
>> 
>> So in essence the main finding is that hearing impairment is essentially modelled by a low pass filter curve? Meaning, it predominantly affects the higher frequencies, rather than manifesting itself by a total signal attenuation?
>> 
>>> 
>>> So, once you adjust to the degree of hearing impairment at, say 4 kHz, the all other levels of impairment correction can be deduced from that degree and the known spectral slope.
>> 
>> Do you mean, the hearing impairment curve tends to start at a specific band, so what you need is to find the band at which the attenuation starts and compensate the attenuation curve that affects the rest of the spectrum? Since as you said, that impairment slopes tend to be similar among individuals.
> 
> 
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