The audibility of speech on TV

[A.S.]

One of my personal irritations is the highly variable quality of TV sound. It's either to loud, too muffled or (never these days) too quiet. And then there is the music, the adverts aggghhhh!

Seems I'm not alone from this PDF on the Institute of Broadcast sound website.

[Stephen PG]

I began to record everything on the commercial channels years ago, as the adverts made me throw things at the TV! And having the TV sound through the Hi-Fi helps enormously, especially since the addition of the SHL5s.

[Labarum]

Haven't time do do anything but quickly scan the PDF.

I am -40dB at 10KHz in my left ear. I am 60. The lack of treble on VHS recording used to make life difficult for me, but broadcast TV I find OK. Much better using the TV toslink out into my DAC and on to the amp and speakers!

What I can't cope with is the TV stereo output messed about to simulate 5.1, which my son's AV amp will do. Sounds from rear channels just send my ears into a spin. It seems OK when the source is true 5.1.

[TSH59]

Labarum. Sorry to read about your hearing.

I took an audibility test on a UK University website using my Sennheiser HD-595s and following all the instructions regarding setting levels etc beforehand. I was -3db at 12khz and -6db at 16khz in the right ear. In the left ear I am -6db at 12khz and can barely hear 16khz at all (I forget how many DB down it was at this level but maybe -12db) In the bass regions there was no problems at only -3db at 30hz.

I am of an age where my upper frequency results looked very unlikely in theory so (suspecting my rigour with the methodology of the test) I had a hearing test done by the optician (ours do hearing tests too) and it was a 'clean sweep'. Apparently I have the hearing of someone in their late 20s. A lifetime eschewing in-ear headphones and NOT trying to get my head close to the bass bins at concerts in my teens, has paid off. I was worried about the decade or more I spent working in large mainframe computer rooms but (so it seems) the continuous noise levels in them must have been below the legal levels.

I have also never really enjoyed replaying music at VERY loud volumes and hate anything but Radio 4 in the car. (R4 fan since I was 17).

I feel sorry for the generation (it must be over thirty years now) of Walkman/iPod/Humungous car stereo users who are destroying/have destroyed their hearing without probably even knowing it. When you can hear someones iPod/MP3 playing through earphones from across a crowded room or can begin to hear a car stereo playing from 400 yards away (with their windows closed and yours too) then I fear for their hearing in later years.

As for the TV ads (Alan) there are mute buttons and teapots to take care of them. Or simply avoiding the 90 percent of drivel that is designed as 'Audience delivery vehicles' for advertisers. Regrettably it is our womenfolk who often make such 'programmes' unavoidable.

If you have a DVD/HDD/Freeview recorder or other similar devices that allow you to 'pause' scheduled TV then you can skip the ads. I often do this with radio programmes via Freeview. Justy hit 'pause' and it automatically starts recording onto the HDD.

[Labarum]

Labarum. Sorry to read about your hearing.

I took an audibility test on a UK University website using my Sennheiser HD-595s and following all the instructions regarding setting levels etc beforehand.

What site was that TSH?

And can someone answer this? With such imbalanced ears why do I hear the stereo image normally centred when the balance control is centred?

[TSH59]

What site was that TSH?

And can someone answer this?

With such imbalanced ears why do I hear the stereo image normally centred when the balance control is centred?

My apologies first. It was not a UK University but an Australian University website.

Here it is....

http://www.phys.unsw.edu.au/jw/hearing.html

Follow the instructions very carefully (heed the warnings) and do the test when there is no ambient noise (I did it late at night). Use good quality 'over the ear' headphones. (I used Sennheiser HD-595s)

[A.S.]

...With such imbalanced ears why do I hear the stereo image normally centred when the balance control is centred?

Your ears, like most of ours as we age, tend to show degradation at the extreme upper frequencies*. Those frequencies are only containing the harmonics of the instruments and it's the harmonics that add the 'sheen' or sparkle to the tone. But the fundamental tones themselves are at perhaps only a tenth (or even just a hundredth) of those upper frequencies. Providing that in the middle or presence frequencies (around 1kHz) your ears are well balanced, the fact that you can hear nothing at ten times that frequency will have no impact at all on your perception of a solid mono image on normal speech or music.

* Why are extreme frequencies more effected than others with age? It's the same problem with stiffness in the joints or muscles with age; the tiny cells that actually sense sound in the ear become stiff and they won't flex as easily, so the fast high-frequency tones just don't make them wobble. And no wobbling means no electrical signal is sent to the brain. The attached picture shows the actual hair cells that convert sound into electrical stimuli. In this patient, there is a shocking contrast between the fairly normal hair cells along the upper ridge (even they are not perfect) and the stumps of cells lower down. This is a classic case of excessive loudness. When those little cells are cut down like trees, they cannot regrow. Sadly, the patient will be deaf for life.

For this reason, I will not be drawn into discussions about how loud our speakers can play, because we have a social responsibility to our users. I have never measured peak loudness because I have respect for my own ears and I design for a full, warm natural sound when listened at a very reasonable listening level. Others design their speakers to be hammered into producing terrifying loudness.

I'm convinced that the most pertinent question a would-be speaker buyer should ask of the manufacturer is this .... "What loudness level did you design these speakers to be played at, to sound natural and life-like?' Here are some possible answers and what I'd suggest in response:

1. Answer: "They'll play as loud as you like. The louder the better!" Verdict: Run a mile
2. Answer: "About 10 on your amplifier volume control". Verdict: They didn't understand the question/are idiots
3. Answer: "Er .... wot? Can you repeat the question ...". Verdict: Run a mile
4. Answer: "About xx-yydB, which audiologists consider a safe listening exposure level for long-term listening". Verdict: these people are worth considering

Then you ask then what xx-yydB actually is. (Do a search for WHO hearing recommendations etc. etc.)

>

[Labarum]

Thanks for your answer, Alan. Yes, the "presence frequencies" I hear well enough. I may have had the hearing loss from birth, though a loud bang on a gunnery range many years ago may have contributed. I have had frequent hearing tests over the years. All Army personnel do. The tests done for the fitting of my digital hearing aid were more interesting. They tested not only the threshold of hearing at all frequencies (as usual) but then the threshold of pain. The hearing aid was then adjusted to work just under the threshold of pain at the lossy frequencies. What I didn't know was that the impaired ear can tolerate less loudness than the healthy ear. That explains why, even as a youngster I hated pop music. It literally pained me!

Well I have the hearing aid, but it makes nothing better. I once put it on when going for a country bike ride, thinking I would hear singing birds - all I heard was the clacking of the dérailleur. I never wore it again!

[Thanos]

Hello,
my greetings.
I was touched from your story, it reminded me the problem my father had for the rest of his life since he was retired. He was a military pilot and he just couldn't bear high frequencies, especially the loud ones. Flying, fighting and aircraft engine noise had damaged especially his right ear. All he could tolerate -as to what we call loud- were low frequencies to a certain degree.

I must say that I myself suffer a bit from the same problem, being now at my early 50's. I remember that Alan had once commented about living in a noisy surround (a big town) vs a quiet countryside. I think he is very right to that. Being away from the city, at a peaceful late evening walk, brought back many times in my ears sounds that I had almost forgotten. And, in the middle of silence, I have a permanent "buzz" in my ears. I don't know if this is reversible...

Anyway, his advice about designing a speaker to exhibit its best at very reasonable listening levels is the finest and scientifically correct approach, protecting our hearing properties. And I do wonder what is going to happen with all those kids, youth if you wish, when they go at live rock concerts, especially at front rows. Is there anybody to tell them and explain to what kind of danger they get themselves exposed at?
Best Regards,
Thanos

[A.S.]

... And I do wonder what is going to happen with all those kids, youth if you wish, when they go at live rock concerts, especially at front rows. Is there anybody to tell them and explain to what kind of danger they get themselves exposed at?

I had my hearing tested about five years ago (and since then) certainly at a time when the regulation of noise and the consequences were perfectly well understood. The audiologist told me that the previous day, he'd measured the hearing of a 17 year old girl who had been in the front row of a concert, next to the PA speakers, without hearing protection. She'd assumed that in the days following the concert her hearing would return to normal - a week later it hadn't and her parents had sought advice from the specialist.

Referring to the picture I attached previously of the hair cells in the ear, he said that her hearing was totally destroyed - every one of those beautiful little hair cell had been scythed. It made me feel physically sick to hear that not even the most powerful modern hearing aid could help her: she will spend the rest of her life in a world of complete silence as a profoundly deaf person. All that from one exposure.

[evs71]

Sadly, due to the sustained and high volume levels, I would be very surprised if rock concerts were not guaranteed to produce some permanent hearing loss regardless of where the listeners sit. Bars and dance/night clubs ( meaning discos ) often play music at extraordinary levels, as well. As the decades go by, and so many people permanently damage their hearing in varying degrees, I'm often left wondering how this can continue.

[EricW]

evs71, and Thanos, I completely agree. I attended many rock concerts, clubs, discos etc. from my teens to my late 20s, and I count myself extraordinarily lucky still to have good hearing (it's been tested) 20 years later. I wonder how society tolerates this situation with little if any attempt at regulation or mitigation of the risk. It's hard to think of any other activity involving equivalent risk of physical harm where people would at least no be advised of the risk they are taking. I'm sure that virtually no one exposing themselves to excessive levels even has any idea what the risk is.