[passernger10000]

I just spent a couple of hours taking a hearing test and plotting the results.

The test was conducted from 20hz to 16,000khz using Logic X as the test tone oscillator feeding into an Apogee DAC and monitoring using Focal Elegia Closed headphones.

Last year I had a hearing test done a local audiologist and I thought how useless this type of test is. They place you in a soundproof room, with an ancient pair of headphones and then use only a few frequencies. I guess most people have done this type of hearing test at one point or the other and unless your completely deaf you'll pass.

What I wanted to find out, is the deviation between my two ears and use a dual mono eq to sort out the differences.

The frequencies used were:

What I found was that my ears do not correlate very well which is perhaps why I have always felt a phantom center with headphones. In fact there was more deviation than correlation. Differences as big as 10db with pretty large swings at very close ranges. Now I realize that this was informal test but the results can not be disregarded. I had worked for over 25 years as studio engineer, that equates to a lot of long listening sessions and ear fatigue plus age. I plan to go through the test process again and publish the results here. I think most people take for granted that their ears hear equally well and I think that is unlikely especially as we age.

I challenge people to take similar tests and see what there own conclusions are. For me, I think my end game system requirements just became that much more affordable. Those of us past 50 years of age should probably donate our expensive gear to youngsters who can actually gain from the performance. That opens up many other topics, such as what your brain has learned about how to listen over time and many other topics on the phycology and physiology of listening.

All in all a very interesting few hours.

 

[sander99]

Differences as big as 10db with pretty large swings at very close ranges.

I don't understand what you measured? Treshold level for detecting the frequency? Searched for equal perceived loudness left and right or between different frequencies?

Just some initial thoughts I had:
I have no idea what would be average values for different ages, but I don't think it is surprising at all that there will be 10 dB differences.

Did you ever think about the following (maybe indirectly related):

If you are listening to sounds coming from your environment, from a certain distance, for example to the drum you mentioned then the sound is subjected to your personal head related transfer function (hrtf) filtering. (The sound is bouncing off your torso, bending round your head, bouncing of your pinnae, bending into your ear canal, etc.)
The resulting filtering of the audio differs per person. If you use headphones a part of this filtering is skipped. Because the part that is skipped differs per person one and the same headphone will sound objectively different to different people.

What is the implication for your measurements? (Just my idea, I am not an hearing expert.)
Your brain will have learned to do some "equalisation" of sounds coming from your environment, including compensation for left-right imbalances. This equalisation would compensate (somewhat) for both your HRTF as well as FR deviations from your physical inner hearing system. Using headphones a part of the HRTF is skipped, so the brains "equalisation" will be compensating for something that is no longer in the sound path.

Also "equalising" can not change the tresholds. But it can achieve a "perceived flat" and balanced sound at higher levels. So differences in tresholds don't need to be a problem (unless the treshold gets extremely high of course [Edit: With age that will happen with the higher frequencies until they are completely gone of course, but for example just loosing one octave 10kHz-20kHz isn't a disaster.]).

 

[passernger10000]

I was measuring hearing thresholds. This is a complicated topic, thank you for your thoughts. I will definitely spend more time on this and post. Hearing should be a far more discussed topic especially when there is so much subjectivity on our forum. If you consider how differently we all hear it makes the job of headphones and loudspeaker designers that much more difficult.

 

[sander99]

If you consider how differently we all hear it makes the job of headphones and loudspeaker designers that much more difficult.

One remark: actually with loudspeakers the situation is very different compared to headphones: the sound from loudspeakers is subjected to your full HRTF filtering just like natural sounds from your environment. So a loudspeaker with a flat frequency response is flat for everyone. (Instead we have other variables to deal with like the influence of the room, but that is not related to differences between people.)

 

[bigshot]

The top octave of human hearing is the least important part of the hearing range. All that exists up there is squeals from CRTs and defective ballasts in florescent lights. Fundamentals in music don't go that high, and any harmonics up there are masked by lower frequencies and are at too low a level to be heard. It would be more interesting to measure the differences between people's hearing in the core range. For instance, I've been told most people have a blind spot in their hearing- a narrow range where their hearing drops out. Usually, it's at a slightly different frequency in each ear. You can only detect it with a slow frequency sweep. This blind spot causes the inability to sound locate certain high frequency squeals. I would be interested to find out how common this blind spot is, and what frequencies it generally lies in.