Simulating hearing impairment accurately

Hi everyone, I’m new to Audacity, and am preparing resources for an educational event for teachers in healthcare. I would appreciate advice on how to adjust a voice recording so that it simulates what a person with hearing impairment would experience (using my own audiogram as an example of moderate hearing loss - 35 dB at 250 Hz, -45 at 500 Hz, -60 at 1000 and 2000 Hz and -45 dB at 3000 Hz). I’ve no training or experience in sound recording techniques and editing, and have tried using the filter curve EQ to “quiet” the recording so that frequencies and decibels match my audiogram, but the speech produced is barely perceptible and doesn’t really sound like my own experience without hearing aids. I also intend to add some loss of spectral detail, but I think I’ve got my head around this.

Many thanks, Janet

You need to know the 0dB reference. Is that normal hearing? i.e. Would the audiogram show 0dB at all frequencies for people with normal hearing?

60dB below normal at 1 & 2kHz is a lot! So suspect (and hope) your hearing isn’t that bad . If I turn-down my TV by 60dB I probably wouldn’t hear it at all…

Does your audiogram show your curve vs. normal? It’s the difference or “loss” that that matters.

And, you need to know if the 0dB reference is flat or a curve. Normal hearing isn’t “flat”. Normal ears are most sensitive at around 2kHz and less sensitive to high & low frequencies.

Even if you accurately matched Audacity’s spectrum to your audiogram, it would not sound like your hearing to you: it would sound like your hearing to an unimpaired person.

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I think you’d have to RMS-normalize it to -20dB, (after adjusting the EQ), to make it loud enough: that’s a typical value for speech recordings.

Thanks @DVDdoug, that’s been really helpful (and makes good sense). It’s improved the authenticity of the recording.

Best wishes, Janet.

Thanks @Trebor, I’ve combined this RMS normalization with @DVDdoug’s advice and the recording is much more realistic. I’m delighted with the result,

Best wishes, Janet

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