Barry
03-06-2011, 22:19
In another thread: http://theartofsound.net/forum/showthread.php?t=11622, Alex (UK) provided a link to an audio high frequency simulator that can provide pure sinusoidal test tones to allow you assess your high frequency hearing.
These sort of tests are always a bit of a minefield: either you want to know, for good or bad, how well your high frequency hearing is being maintained, or knowing that you spent much of your misspent youth attending very loud rock concerts and simply don’t want to know by how much your hearing has been damaged. Then there are those who regard these demonstrations as a challenge (the audio equivalent of “how far up the wall can you piss?”) and either as a face-saving exercise when in denial or simply as an excuse to brag, will often report results that are unlikely given their age.
Even so I gave it a go and found I could easily hear the 12kHz tone but none 14kHz or higher. Given that I’m 61, and like it or not, one starts to progressively loose high frequency hearing somewhere between age 40 and 50, I should have been content (if not pleased) with that result. But no, I put it down to the poor fidelity of the headphones I was using – the sort that are handed out on planes for the in-flight entertainment.
So I padded over to my “pipe and slippers” system and put the Hi Fi News & Record Review Test Disc (HFN 003) into the CD player and ‘listened’ to tracks 33 through to 36: spot frequencies at 10, 16, 18 and 20kHz. Now these tones are recorded at a very high level (0dB), but to no avail the 10kHz tone was loud and obvious but the rest silence apart from a low level buzz these high level high frequencies seem to have upset the Quad 405-2; the persistency of which was such that it remained when the preamp was switched to another source and could only be eliminated by switching the power amp off and then on again!
So far so good - or should that be bad? I next pulled out a demonstration record made for JBL Speakers to help their dealers demonstrate to customers what they ought to listening for. (The record is called “Sessions”, there is no record number but it was recorded by Capitol in 1973. I bought my copy in the very early ‘80s.) No, it’s not a blatant piece of marketing propaganda but actually a very useful demonstration disc. Not surprisingly it contains a range of test tones with the intention of demonstrating what useful frequency response you need. In doing so I found my electrostatic speakers reproduced the lowest note on a string bass (42Hz) with excellent fidelity. But we are talking high frequencies here and the record has a downward sweeping tone from 20kHz to 10kHz. This time I could hear even less, though I fancied I could just make out tones up to 13kHz.
Now there have been a couple of posts here to the effect that some members who have well recognised hearing problems, such as tinnitus as well as high frequency loss have asked whether they need a full range system. My immediate reply is YES, for reasons that I will now explain. Unless you listen exclusively to either pipe organ or to synthesisers, all musical instruments have their fundamentals lying between 38Hz (lowest note on a contra-bassoon) at one end and 4.698kHz (the top note of a piccolo) at the other. Now there are pitchless instruments that do not have a natural pitch, their pitch depends on how they are played: drums (excepting tympani); cymbals and triangle, but only snare drums and the metallophones have response going beyond 4kHz. Yet it is the presence of harmonics, the overtones that give instruments their timbre, and these overtones can extend beyond 15kHz.
So we seem to have a dichotomy here. There are some of us who recognise we have age-related hearing loss (presbycusis) yet need to be able ‘hear’ high frequency harmonics so as to give instruments their character. Well don’t worry – you still need a system with an extended high frequency response and even though you cannot directly hear high frequency tones, you will perceive them as harmonics. Returning to the JBL demonstration record “Sessions”, there is a very useful and interesting track consisting of a solo violin with the intention of demonstrating attack and the start of the notes. This track is repeated three times, but at a point roughly halfway through each track, all frequencies above 15kHz, then 12kHz and in the third 10kHz, are filtered out. Now as I have said, I cannot hear direct tones higher than 12kHz, yet the sense of attack and ‘air’ of the violin as the higher frequencies are filtered out is obvious and immediate. It can be heard at 15kHz and is quite obvious at 12kHz – even more so at 10kHz!
So there you go; even though you might not be able to hear a pure note above say 10kHz, you will most certainly perceive the presence of harmonics at frequencies higher than this and you still need a system that can reproduces these frequencies.
One final point – some might have tested their own high frequency hearing and found that there is not necessarily a monotonic roll off with frequency. Again don’t worry. For years through my late forties and early fifties my hearing fell off at 14-15kHz, with total silence at 16 and 17kHz only to find it returned at 18kHz and then promptly fell away again. I blame a certain ‘Nine Below Zero’ concert I attended in my mid thirties!
These sort of tests are always a bit of a minefield: either you want to know, for good or bad, how well your high frequency hearing is being maintained, or knowing that you spent much of your misspent youth attending very loud rock concerts and simply don’t want to know by how much your hearing has been damaged. Then there are those who regard these demonstrations as a challenge (the audio equivalent of “how far up the wall can you piss?”) and either as a face-saving exercise when in denial or simply as an excuse to brag, will often report results that are unlikely given their age.
Even so I gave it a go and found I could easily hear the 12kHz tone but none 14kHz or higher. Given that I’m 61, and like it or not, one starts to progressively loose high frequency hearing somewhere between age 40 and 50, I should have been content (if not pleased) with that result. But no, I put it down to the poor fidelity of the headphones I was using – the sort that are handed out on planes for the in-flight entertainment.
So I padded over to my “pipe and slippers” system and put the Hi Fi News & Record Review Test Disc (HFN 003) into the CD player and ‘listened’ to tracks 33 through to 36: spot frequencies at 10, 16, 18 and 20kHz. Now these tones are recorded at a very high level (0dB), but to no avail the 10kHz tone was loud and obvious but the rest silence apart from a low level buzz these high level high frequencies seem to have upset the Quad 405-2; the persistency of which was such that it remained when the preamp was switched to another source and could only be eliminated by switching the power amp off and then on again!
So far so good - or should that be bad? I next pulled out a demonstration record made for JBL Speakers to help their dealers demonstrate to customers what they ought to listening for. (The record is called “Sessions”, there is no record number but it was recorded by Capitol in 1973. I bought my copy in the very early ‘80s.) No, it’s not a blatant piece of marketing propaganda but actually a very useful demonstration disc. Not surprisingly it contains a range of test tones with the intention of demonstrating what useful frequency response you need. In doing so I found my electrostatic speakers reproduced the lowest note on a string bass (42Hz) with excellent fidelity. But we are talking high frequencies here and the record has a downward sweeping tone from 20kHz to 10kHz. This time I could hear even less, though I fancied I could just make out tones up to 13kHz.
Now there have been a couple of posts here to the effect that some members who have well recognised hearing problems, such as tinnitus as well as high frequency loss have asked whether they need a full range system. My immediate reply is YES, for reasons that I will now explain. Unless you listen exclusively to either pipe organ or to synthesisers, all musical instruments have their fundamentals lying between 38Hz (lowest note on a contra-bassoon) at one end and 4.698kHz (the top note of a piccolo) at the other. Now there are pitchless instruments that do not have a natural pitch, their pitch depends on how they are played: drums (excepting tympani); cymbals and triangle, but only snare drums and the metallophones have response going beyond 4kHz. Yet it is the presence of harmonics, the overtones that give instruments their timbre, and these overtones can extend beyond 15kHz.
So we seem to have a dichotomy here. There are some of us who recognise we have age-related hearing loss (presbycusis) yet need to be able ‘hear’ high frequency harmonics so as to give instruments their character. Well don’t worry – you still need a system with an extended high frequency response and even though you cannot directly hear high frequency tones, you will perceive them as harmonics. Returning to the JBL demonstration record “Sessions”, there is a very useful and interesting track consisting of a solo violin with the intention of demonstrating attack and the start of the notes. This track is repeated three times, but at a point roughly halfway through each track, all frequencies above 15kHz, then 12kHz and in the third 10kHz, are filtered out. Now as I have said, I cannot hear direct tones higher than 12kHz, yet the sense of attack and ‘air’ of the violin as the higher frequencies are filtered out is obvious and immediate. It can be heard at 15kHz and is quite obvious at 12kHz – even more so at 10kHz!
So there you go; even though you might not be able to hear a pure note above say 10kHz, you will most certainly perceive the presence of harmonics at frequencies higher than this and you still need a system that can reproduces these frequencies.
One final point – some might have tested their own high frequency hearing and found that there is not necessarily a monotonic roll off with frequency. Again don’t worry. For years through my late forties and early fifties my hearing fell off at 14-15kHz, with total silence at 16 and 17kHz only to find it returned at 18kHz and then promptly fell away again. I blame a certain ‘Nine Below Zero’ concert I attended in my mid thirties!