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Relevant Warnings Can Help Prevent Hearing Loss

Ahead of NAB Show, Radio asked TC Electronic's Thomas Lund about his upcoming presentation

What is your full name and title?

TL: Thomas Lund, CTO Broadcast & Production.

You’re speaking at the NAB Show about personal broadcast platforms, loudness and hearing loss. What’s the headline here; what is the main conclusion of your paper?

TL: That a PMP (Personal Media Player, i.e. smartphone, iPod, iPad etc.) should have a gain structure not only aimed at playing crushed pop music, and that it should also be capable of informing the listener when she is over-dosing audio. Right now, using a PMP is like driving a car without a speedometer or a cruise control. It’s tempting to go faster and faster as you become numb to speed.

Many of our readers are owners, managers and engineers of radio stations; others are involved in new media like streaming and podcasting; and many are involved in both. Why is this topic important to them?

TL: Currently, there is a very small level sweet spot where sound can be heard under a variety of listening conditions while not sacrificing sound quality. The average level I’m talking about is around -16 LKFS.

Why is TC Electronic involved in this issue?

TL: Production, mastering, distribution and consumption forms a circle with feedback. Right now we have a vicious one running, where a low headroom in distribution (Internet radio, YouTube, Pandora, Spotify and others) is combined with a low sound quality at the consumer (small speakers, flat panel TVs, mediocre PMPs). This is turn drives squashing up and audio quality down in production and mastering.

The vicious circle has actually destroyed 10 years of our recent music heritage, and older well-sounding albums are remastered and crushed. One example among thousands is Paul Simon’s beautiful Graceland � which I normally refer to as “Disgraceland” in its 2012 remastering.

TC is involved because that’s what any audio professional should be. From a commercial point of view, there will also not be much point in designing quality processing, loudspeakers etc. if the vicious circle runs for much longer.

You helped set up a work group about this topic. Tell us a bit about that.

TL: CENELEC is the tech standardization arm of the European Commission. Between 2.5 and 10 million people in that region is expected to develop early hearing loss as a direct result of listening to much and too loudly to PMPs. Five years ago, the commission decided that education and protection of users was needed. Hazard-based legislation is therefore now in place to limit the maxiumum sound exposure level from any PMP sold in Europe.

However, PMPs must include dose estimation based on actual audio so a screaming Internet radio station or pop track gives an earlier warning than Graceland (from 1986) or an episode of Game of Thrones. I spoke about that at a CENELEC meeting and suddenly found myself asked to be “convenor” of a work group.

How do “loudness wars” play into this discussion?

TL: With good dose estimation in PMPs, it would be even more futile to squash music at the mastering stage. You only accomplish that it’s turned down later – but all the added distortion will still be there. Therefore, PMP dose estimation and loudness normalization in broadcast both help calm the loudness wars.

Obviously many of the details in your presentation are beyond the scope of this interview. But can you list some main conclusions for our readers?

TL: PMPs should have an easy understandable way of letting users know about the sound dose they had received, for instance expressed in % of max safe per day.

Another important conclusion is that BS.1770 loudness normalization in itself is benign to reduce PMP sound exposure.

Personally, I think relevant warnings is the most important � not that a device turns itself down automatically. If you were in a subway 30 minutes per day, no big deal to have the clock ticking a bit faster during those periods, as long as you become aware that sound level should come down when you exit.

What is the biggest recent change in the area of loudness that radio industry people need to know about?

TL: BS.1770 normalization is an easy place to improve sound quality. It also allows you back off FM processors a lot. According to recent tests in the Netherlands, Sweden and Germany, the coverage area can actually be expanded by reducing FM level because of how modern receivers are designed.

What should we expect next in that area?

TL: EBU is about to recommend BS.1770 normalization in radio, download and streaming.