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Feb 24, 2023 128 likes •481 views

10/17/2018 Cory Portnuff, AuD, PhD, CPS/A Board Certified, Clinical Audiologist UCHealth Assistant Clinical Professor Department of Otolaryngology, School of Medicine University of Colorado Denver Following this presentation, learners

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10/17/2018 1 Cory Portnuff, AuD, PhD, CPS/A

Board Certified, Clinical Audiologist UCHealth Assistant Clinical Professor Department of Otolaryngology, School of Medicine University of Colorado Denver

 Following this presentation, learners should be able to

select and dispense hearing protection which is appropriate and effective for musicians and music consumers.

 Following this presentation, learners should be able to

better program hearing aids for music and be able to recommend technology options for music listening.

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10/17/2018 2  How can a musician reduce his/her exposure?  Exposure is Level + Time  Reduce playing level  Reduce playing time  Reduce exposure from other instruments

  • E.g. highly directional instruments on risers
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10/17/2018 3  Earplugs  In-Ear Monitors

  • Both HPDs and Noise Controls

Musicians and earplugs…

  • Many musicians are resistant to earplugs
  • Good, but not great fidelity (loss of some

timbre)

  • Auditory memory of high levels
  • Comfort over playing time
  • Audibility of own instrument and others
  • Bad experiences with foam earplugs
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10/17/2018 4  Custom

  • 9, 15, 25 dB of attenuation
  • $150-$200
  • Requires ear impressions by an audiologist

 Universal fit

  • “Ety-plug”, “ER-20”
  • 20 dB of attenuation
  • $12-20
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10/17/2018 5  Use REAT measures with each earplug fit, either under

Circumaural earphones or in soundfield with masking to the contralateral ear (~50 dB SL).

  • At minimum: 250 Hz, 4000 Hz
  • Better: 250, 500, 1000, 2000 Hz
  • Best:

▪ 250, 1000, 2000, 4000 Hz ▪ 250, 500, 2000, 4000 Hz

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 REAT vs. MIRE

Probe mic Modified probe Open ear Portnuff & Price, 2016

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10/17/2018 6  Is this the best you can offer me?

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 Auditory memory and music  Avoiding performance injury  Ear training  Enrollment in a hearing conservation program

  • Annual review of exposure & exposure controls
  • Annual evaluation of hearing
  • Annual review of hearing protection use
  • Annual education and training about hearing

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10/17/2018 7  Etymotic Research Music Pro

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10/17/2018 8

“… about 50,000 working musicians use IEMs”

  • Michael Santucci (Beck, 2016)

 Isolation?

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10/17/2018 9  Improved sound quality & stereo sound  Improved pitch perception, timing  Consistent sound between venues.  Mobility  Reduced risk of feedback  Reduced vocal fatigue  Lower sound levels for audience

ACRYLIC

 Many companies  Variable seal  Can be fit with canal coating or

vinyl canal to improve seal

 Wide cost range

SILICONE

 One company  Excellent seal  Somewhat bulky  Most expensive (though some cost

range)

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10/17/2018 10

Federman & Ricketts (2008)

Federman & Ricketts (2008)

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10/17/2018 11  Requires education and training!

A priori, Musicians care about performance, not about preserving hearing.

 Occlusion

  • Deep fit helps

 Difficulty hearing stage noise

  • Take one out?
  • Stage can be miked
  • Sensaphonics 3D Active Ambient system
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10/17/2018 12

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 As audiologists, we’re trained that the most important

thing for our patients is COMMUNICATION Are hearing aids a communication tool or a quality-of-life tool? (what would CMS say about this?)

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10/17/2018 13  Think about hearing aid features and signal processing.

What are the main features of a hearing aid that are targeted at hearing speech well?

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 WDRC to ensure audibility  Expansion to reduce low-level sound annoyance  Limited MPO for comfort  Directional microphones for noise  Noise reduction & speech enhancement algorithms  Anti-feedback systems

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10/17/2018 14  Long term average spectrum

  • Speech: low-frequency emphasis, some lower-intensity high

frequency components

  • Music: Variable in both frequency and intensity. Significant

dynamic range.

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10/17/2018 15

(Chasin 2014)

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 Overall intensity

  • Speech: 65 dBA @ 1m. ± 12 dB

▪ Range: 53-77 dB SPL ▪ Shouted speech: up to 90 dBA

  • Music: Wide range.

▪ Brushes in a jazz song: 20-30 dBA ▪ Brass in Wagner’s Ring Cycle: 105 dBA, peaks at 120 dBA ▪ (Recorded music can be any level)

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10/17/2018 16  Crest factors

  • Speech: 12 dB
  • Music: 14-20 dB

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 Discrimination vs. Quality components

  • Speech is mostly low-frequency energy and high frequency clarity (AI).

Quality is important, but not critical.

  • Music perceptual requirements depends on the instrument…. Pitch

discrimination required, timbre (quality) is key.

▪ Violins need to hear the balance between low and high frequencies. ▪ Clarinets only need to hear the lower frequency energy.

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10/17/2018 17  WDRC compression

  • Reduces dynamic range
  • Compression time constants matter

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Croghan et al 2014

 Long term average spectrum

  • Effect of WDRC?
  • Effect of multi-channel amplification?

▪ Interchannel distortion

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WDRC warps the signal envelope, reducing the spectral and temporal contrasts that listeners commonly utilize in music perception (Plomp, 1988).

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10/17/2018 18  Overall intensity

  • Effect of WDRC?
  • Effect of MPO limits (peak compression)?

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 Crest factors

  • Effect of WDRC on dynamic range?
  • Effect of transient management algorithms?
  • Effect of feedback suppression algorithms?
  • Effect of speech enhancement/noise reduction?

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10/17/2018 19  Discrimination vs. quality

ANY modification of the sound signal is distortion Some distortion is helpful – some is not

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 WDRC to ensure audibility  Expansion to reduce low-level sound annoyance  Limited MPO for comfort  Directional microphones for noise  Noise reduction & speech enhancement algorithms  Anti-feedback systems

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10/17/2018 20

GROUP QUESTION… What are the components of a hearing aid?

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What are the key components for music?

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10/17/2018 21  The Analog to Digital Converter

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 Most hearing aids have some degree of limiting of inputs

>85 dB SPL

 Let’s listen! http://www.chasin.ca/distorted_music/

  • Limiting at: 115 dB SPL, 105 dB SPL, 96 dB SPL, 92 dB SPL,

and 115 dB SPL

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10/17/2018 22

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10/17/2018 23

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 Dynamic range also limited by processor –  16 bit = 96 dB. 24 bit = 144 dB

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 16 bit minimum, though most manufacturers are moving

to 24 or 32 bit systems.

  • “24” bit systems are really closer to 18-19 bits… but may allow

up to 119 dB SPL inputs.

 Multi-core DSP chips allow for faster processing.

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10/17/2018 25  Increasing every day.  Is this a good thing?

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 Each channel “crossover” has the potential for distortion

products

  • Worse with different compression ratios in adjacent channels

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10/17/2018 26  Variable, hearing aid to hearing aid.  Generally, fast attack times  Release times vary significantly.

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 Transient management  Feedback suppression  Noise reduction  Speech enhancement

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10/17/2018 27  One channel  No advanced features

But, what do we do about the real world of audiology?

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 Consider the input…  “Lower the (input) volume, increase the Gain”

 Chasin, 2014

  • Physically reduce the input
  • Digital shifting of dynamic range?

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10/17/2018 28

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10/17/2018 29

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 Consider input characteristics of the hearing aid,

including patient’s needs.

  • Consider modifying microphone as needed.

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10 20 30 40 50 60 70 80 90 100 2000 4000 6000 8000 10000 Frequency (Hz) O u tp u t (d B S P L ) Unattenuated output Adhear or Scotch Tape Adhear and Whiteout

Chasin, 2008

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10/17/2018 30  Change the input

  • Microphone: Use of an FM system or remote microphone

(designed for higher input, close to mouth)

  • Recorded music: Direct audio input

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 Compression time constants

  • Slowest release possible! Preserves temporal envelope.

▪ Oticon “identities”

 Compression kneepoints

  • 5-8 dB above speech is ideal
  • Reduced compression ratio

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10/17/2018 31  Turn off advanced features…

  • Noise reduction
  • Speech enhancement
  • Frequency lowering
  • Transient management
  • Tinnitus maskers
  • Probably automatic directional microphones

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 MPO

  • Max it out, unless you have loudness tolerance issues.
  • If so, OSPL 90 should be 6 dB higher than that for speech, to

account for higher crest factors of music *Note – this only matters for live music/loud music.

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10/17/2018 32  MOST:

  • Increase low frequency gain
  • Attempt to “widen bandwidth”

 SOME:

  • Reduce compression ratios
  • Turn off some advanced features

 A FEW:

  • Change compression constants to long release times

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 VERY FEW:

  • Turn off feedback cancellation
  • Turn off frequency lowering (if enabled when music program is

created)

  • Shift threshold kneepoint up
  • Modify input dynamic range

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10/17/2018 33  In a live music setting, is a hearing aid necessary for the

patient?

 What about recorded music?

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 Hearing aids are not ideal, on face, for music  Hearing aids can be modified for speech

  • Some are better than others out of the box!

 Always consider the music input

  • Live music, loud music, soft music?
  • Will it overdrive the A/D converter?

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10/17/2018 34

Join the Experts… Get the Expertise www.hearingconservation.org Questions? Cory.Portnuff@uchealth.org