1. Geoff are you saying headphones are not good for hearing as the article implies
    I thought Headphones if used and designed by proper Manufacturers were superb

  2. Hi Fraser,

    No. What this article implies (admittedly, with too little information) is that a radical balance shift in a pair of headphones should be considered to have some impact on hearing loss, if used improperly.

    What the article should have discussed (and I plan to talk about in a future posting) is that, if a manufacturer is “playing by the rules” then the pair of headphones in the store has passed a test called EN50332 where a filtered noise signal is sent to the headphones and the output sound pressure level is measured. If they are to be considered as “legal” then the maximum sound cannot exceed a stated threshold (I’m oversimplifying the description a little here…)

    The catch is that the signal that’s used to do the measurement is rolled off in the low end and the high end (ostensibly to better match the spectrum of music) as you can see in Figure 1 of this document. The measurement is A-weighted, which also rolls off the low end and the high end (to mimic the behaviour of the human ear at lower listening levels).

    This means that the measurement technique is “deaf” to the low-frequency and high-frequency behaviour of the headphones, since the measurement is only “looking at” the mid-band frequencies.

    So, you can have two pairs of headphones that both pass the EN50332 test – one with a “flat” response and the other with a huge bass boost. Assuming that they both have the same sensitivity, then if you apply the same voltage (or power, depending on how you want to measure the sensitivity) to them, then the one with the bass boost will be louder. How much louder depends on the frequency band that is boosted, and by how much.

    So, even assuming that a pair of headphones on the shelf in the store meet the EN50332 requirements (and there’s no guarantee of that…) a bass-heavy headphone will be louder.

    Of course, in order to induce hearing loss, you have to listen to loud sounds for a long time (the louder the sound, the less time it takes to damage your hearing). So, even the most bass-heavy of headphones will not cause any problems if you just turn down the volume.

    However, if you have two kids, both with an iPhone, both set to maximum, both with headphones that meet EN50332 – but one kid has bass-heavy headphones and the other has flat ones, I’ll put my money on the bass-head losing his hearing faster.


  3. Hi Geoff
    Thanks for the reply very interesting Subject and I didn’t know about the EN50332
    test look forward to more articles in your future posting.

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