My father is 88 years old. He has various hearing frequency deficiencies.. He hears lows as very boomy and "foggy", and some high freq. he's missing entirely. Not sure exactly which numbers.. but... whenever I'm at his home he is always blasting his t.v. in order to hear it. I decided to try out the BOSE PAS on him. I ran the audio outputs from his t.v. directly into the BOSE and used the 05 preset, as it was already set to my specs. I eq'd the remote flat, except I put the high end at about 2 oclock. Amazingly, he could understand the program we were watching and the actual output db (I'm certain) was lower than previously.. although I did not have any scientific means of measuring this.. I could also talk above the t.v., which I was not able to do previously.. I suppose, he could have been humoring me, (since he learned that I dished out 2Gs for the system, and perhaps he just wanted me to get my p.a. out of his living room.?? . but this may be something for BOSE to give a try, maybe to sell to upscale retirement centers, etc..?? who knows..

This *is* very intersting. We've heard this before a few times where the additional clarity and volume reduction results in a better experience for older listeners. I'm not sure why this is, I can guess/postulate a bunch of reasons, but I don't have any clear, scientific reasons for this common experience. I wonder if there's ever been a study.

Keep the stories coming though, maybe there's something that will become evident.

Thanks,
Stev

I suffer from congenital hearing loss.
About 50db in one ear, maybe 40db in the other.
I have a flat frequency response, just 40+db down.

People who do not suffer hearing loss really have no idea what its like.

As a means to explain it – I did the following experiment for my wife (a physician) and her parents.

I recorded my voice using a mic to MD (OK – there is some compression going on there but for this non scientific “simulation” that can be ignored).

I made sure that the channel settings and the output master settings on the mixer were close to unity – i.e. I was barely peaking into the reds. The mixer – a Pioneer DJM-500 has decent headroom.

I made sure to speak evenly and at a steady tone. Years in Radio have prepared me for this J.

I then played back that recording into the board and recorded it as the “A” track.

Next I configured a gate/expander/compressor/limiter. I have a dbx 1066.

I started with the config below and then twiddled by hand until I felt it was an appropriate simulation. It wasn’t, but it gives one an idea of how it sounds.

To make the experiment “extreme” in order to give people a flavor of what it sounds like I first checked the levels on my voice. When speaking I used the –20db to 0db sections on the meter. I tried to set the gate cut off in the lower middle of the dynamic range of the speaking – in this example about –15db.

The compressor side is less important – because IMHO the human hear as an incredibly large about of dynamic headroom – and pain makes one move away. But to simulate the “muddyness” that I can often hear – I set the cutoff of the compressor at a setting a bit above gate, at -10db and set the ratio at about 3:1.

The limiter I ran at +5db. This give one the sense of the dynamic headroom SQUEEZE that I often experience.

The expander is probably the best simulation (from a conceptual standpoint) of hearing loss – it sets the slope of the sound fade off harder than the sound fades out. But it doesn’t really simulate the “drop off” that one experiences with hearing loss. Hence the need for the “gate”. I set the ratio at 5:1.

The voice was a tad harsher clipped than I really hear things – but it gave them a real good idea of “my world”.
I played the same track back trough the dbx to give them a B track.

So

What does this have to do with PAS?

A lot actually.

As I understand it (massive simplification here)
– a typical speaker will radiate sound waves as a cone section out of a sphere and the db levels fall off at the CUBE root of the distance.
– The PAS generates a cylinder sound waves and the db falls off a the SQUARE root of the distance.

The human ears are an amazing instrument – the signal process capability of the human ear coupled with the brain and a bio feedback mechanism (turn your head) means that a human can pick out and focus on a single voice in a crowded room. I have not heard of ANY processor that can do that in REAL TIME (and better yet – fit into a hearing aid).

Hearing loss (IMHO) is two things
- a major decrease in dynamic range (the upper pain threshold is still there – it’s the lower floor cut off that is raised – often massively)
- A raised floor for the cutoff of intelligibility.

IMHO the human is IS in fact a VERY sensitive instrument. I would not be surprised at how “fine” a gradient in db sensitivity the human ear might have.

Heres why I think the PAS sounds so good to a person with hearing loss –

When you turn your head listening to a normal speaker – the db falls at the CUBE of the distance. Your brain and ears can detect that db fall off. More importantly when you have a hearing loss that db fall off drops the signal BELOW your “gate” threashold – you LOSE the signal.

This signal loss is VERY jarring and quite disorienting – it’s as if the English you were hearing was suddenly transformed into oh Mandarin (which you cant understand).
As a human you develop hundreds of coping mechanism to deal with avoiding this “pain”.

The PAS has a slower fall of in DB. Turning your head or moving is less disorienting. You do NOT have to concentrate as much to hear. You are more relaxed.
Trust me – you can get awfully tense when STRAINING to hear all the time (basically you compensate for the intelligibility of the voices by cranking up the brain processing power. This is do-able, but tiring.)

This message has been edited. Last edited by: EWong,

quote:

Trust me – you can get awfully tense when STRAINING to hear all the time

Thanks from a fellow sufferer for that observance, straining is constant and no fun. I have to listen very carefully (& read lips) to get past the shriek of my tinitus.

Guitarwoman, you certainly are onto something there.

Most TV speakers are cheap crap and when you turn it up it becomes more apparent. The Bose must be wonderful, I haven't tried it yet. I usually just turn on the closed captions. I look forward to trying that out.

Pete

EWong,

Thanks for that run down. I think I'll go turn down my L1 right now. That's scary stuff IMO.

Steve

PS Great hypothesis too.

Hi guitarwoman,
I really appreciate your telling us this story about your father. Of course, we didn't set out to help those with hearing difficulties, but it gives me a special kind of good feeling to learn that even one person experiences an improvement like this from our work. As far as a product goes, as Ken says, "we are listening ..."

But I worry about the cost of such a product, even if it didn't need to play very loud. Is there a less expensive solution? Do you think headphones with some EQ would work for your father? Maybe wearing them is a problem (discomfort, wires, et cetera) or we'd all be seeing more of this. Just a thought.

Chris

Hi EWong,
I really loved your description of your signal processing demonstration--very apt. But I would like to offer some clarifications on the confusing subject of sound falling off with distance.

What makes the subject confusing is that some people are talking about how intensity falls off and some are talking about how pressure falls off and we don't always make clear which one we mean. (I'm just as guilty of this myself.) But the two quantities don't fall off at the same rate, because intensity is generally proportional to pressure squared, as we'll see below. To make things worse, we also talk about sound in decibels (dBSPL), which is what most hand-held meters give readings in. So a lot of different numbers get used and no wonder it's confusing. ST probably already has a table somewhere that shows all this, but here's my version of the math.

In a spherically spreading sound field,
    pressure
            falls off as "one over r" from the source, ( 1/r )
            drops by half each time you double the distance
    intensity
            falls off as "one over r squared" from the source, ( 1/r^2 )
            drops by one quarter each time you double the distance
    dBSPL (decibels)
            drops by 6 dB each time you double the distance

In a cylindrically spreading sound field,
    pressure
            falls off as "one over square root of r" from the source ( 1/sqrt(r) )
            drops by a factor of 0.7 each time you double the distance
    intensity
            falls off as "one over r" from the source ( 1/r )
            drops by half each time you double the distance
    dBSPL (decibels)
            drops by 3 dB each time you double the distance

From this, you see that the maximum point of confusion is that the phrase "one over r" applies BOTH to the pressure of a spherical source AND to the intensity of a cylindrical source. What this generally boils down to is that you just can't figure out what people are trying to say unless you already know.

The safest thing for all of us to say would be to refer to the dBSPL number, because that quantity is most closely related to the way we judge sound levels with our ears. But I'm afraid we won't be able to retrain ourselves at this late date, so no doubt we'll continue to confuse people when we speak quickly about this phenomenon. But I hope this lengthy explanation allows more people to "already know" what we mean.
Chris

Chris-at-Bose

Thanks for the correct definition.

As an engineer by schooling - I appreciate knowing the hard math.

And then there's "field math" where the real world of multiple conflicting influence inputs means "seat of the pants" engineering

I guess the short answer is that
a) cylindrical spreading sound field's db levels fall off SLOWER than spherical spreading sound fields
b) people with hearing loss have a MUCH STEEPER db level fall off (as they hear the sound)

What this means is that if a person with good hearing were to "turn their head" - they might experience "x" db level fall off. The same person with a mid to high level of hearing loss (myself as an example) will hear a 2x or 3x db level fall off. Its as if we "jumped" back 20 or 30 feet.

The second main point is that people with hearing loss have a GATE built into their hearing. People with normal hearing dont have this (or the "gate" is below the ambient noise floor and thus isnt a problem - in particular since the human ear's "comb" function allows them to pick out sounds from an noisy background).

This means that very often the act of turning one's head takes a voice that you are listening to and drops it into the "gate" db range. And the signal "drops out".

If you have tinitus (aka ringing ears) it gets even more difficult as the "background" noise is not actually in the background but in the "singnal processor" (i.e. the brain) itself and therefore is VERY difficult (nigh on impossible) to comb out.

If I could recall all my FFT math - my guess is that the transform would NOT show "spikes" that could be filtered (i.e. the noise is random) but be a solid block across the signal...

Again - the fact that the human brain manages to do real time FFT transforms and filters out noize is simply astounding to me....

As soon as things get back to normal around here, the post above will be incorporated into the Unofficial Users' Guide.

Thanks Chris.

quote:

But I worry about the cost of such a product, even if it didn't need to play very loud. Is there a less expensive solution? Do you think headphones with some EQ would work for your father? Maybe wearing them is a problem (discomfort, wires, et cetera) or we'd all be seeing more of this. Just a thought.
Chris

The cost of a PAS is certainly a factor - a $1.7K "speaker" is out of the budget of many "TV" watchers.

I would guess that you arent familiar with the cost of hearing aids either - they are often in the price range of a double bass PAS - PER EAR.

The sad thing is that most people arent anywhere near as familiar with sound "concepts" as people on this list. Start talking db levels, EQ curves, noise floor and people are L-O-S-T. And therefore at the prey of hearing aid sales people.

Miraacle Ear lost a huge law suit on their "pick a voice out in a room" ad pitch.

I cant see doing that with a room full of processors, computing power and with a reasonable lag time nevertheless in real time and in a package small enough to fit in your ear.

Like glasses - each person has a different hearing loss pattern
- EQ curves
- dB levels
- ambient noise
all vary patient to patient and ear to ear.

As if Bose needed a new market to get into (hearing aids)... although I would welcome Bose level engineering being applied to the field.

quote:

Originally posted by Chris-at-Bose:
..But I worry about the cost of such a product, even if it didn't need to play very loud. Is there a less expensive solution? Do you think headphones with some EQ would work ... Maybe wearing them is a problem (discomfort, wires, et cetera) or we'd all be seeing more of this...

I use wireless headphones on occassion for the TV (when my wife doesn't care about the show I'm watching and she wants to concentrate on something else).

However, headphones are moderately (some might say STRONGLY) "anti-social" -- you can't casually walk in, sit for a while, wander to another room (with inexpensive infrared wireless, you lose the signal), wander back, casually engage in conversation during the commercials, etc...

How about a "mini" Cylindrical Radiator(tm) of 1" speakers for low-power applications (e.g.: TV or A/V setups) -- with a matching LF unit, of course. As TV's get larger, having a 2' high speaker column attached is no longer so visually outrageous!

quote:

Originally posted by Dan Cornett:
How about a "mini" Cylindrical Radiator(tm) of 1" speakers for low-power applications (e.g.: TV or A/V setups) -- with a matching LF unit, of course. As TV's get larger, having a 2' high speaker column attached is no longer so visually outrageous!

As I understand it...

You cant get a moderate cylindrical wave effect with a 2' speaker column.

And even if you did - the TV would "turn off" if you stood up. (recall the vertical dispersion is minimal).

Me thinks that a 3' column is a MINIMUM to get the effect... which strangely enough is about the height of an MA12 array.

When I finally get an MA12 array (I plan to go "passive PAS" by using MA12 arrays) I'll experiment at home.

One of the reasons for going MA12 instead of PAS is that I actually PLAN to mount the speaker at home and simply take it off the wall when I do a gig (about 2-3 times a year).

yeah - I lose out on all the other PAS features...

quote:

As soon as things get back to normal around here, the post above will be incorporated into the Unofficial Users' Guide.

Thanks, ST, I knew you'd have the right place for that post to go. But ... what makes you think things will EVER be normal around here?

Hi again,
In my father's situation, he'd probably not use headphones, or purchase a PAS (at least for himself) because he's been nearly deaf for so long that it's not "his" problem nearly as much as it is a problem for the rest of the family. Because of his hearing deficiencies, others are subject to the annoying and probably-deafening decible levels of what he watches. However, with the right marketing, .. "if you build it, they will come".. My father did already spend at least $1500 in the past on "high-tech" ear pieces that ultimately did not perform as advertised... so I don't think $2,000 is unreasonable for a system that could benefit an entire family that may have to endure lving with someone like my father.

Well my hearing is fine, (apart from the normal ageing HF loss) but I listen to all my (PRIVATE TV) viewing via headphones.
By private, I mean anything that my wife is not interested in viewing. And she will do the same if there is something that particularly annoys me. Common courtesy really.
Also when she goes to bed and I want to watch a movie or sports, (which because of our time difference, are sometimes broadcast much later,) then she is not disturbed.
May I respectfully suggest that for his next birthday, or fathers day, or whatever, that someone buys your father a set of radio frequency headphones, for his TV viewing pleasure.
It will make his household a more pleasent and less stressful place to be, for all the family.
Getting rid of "STRESS POINTS" in our lives is the key to health and happiness.

If you need any advise on brands or models etc, just ask, there is a wealth of knowledge here on the forum.

This message has been edited. Last edited by: IanHB,

Guitarwoman,

Bose does make SEVERAL home audio products, including one at $500 called the Cinemate that plugs directly into the TV's audio outputs.

Many customers I've dealt with over the years with hearing challenges comment on drastic improvements in hearing a TV with just a simple well designed home audio system instead of just using the TV speakers or "old" speaker systems.

Just a thought.

I've been performing for free at local rest homes for almost two years with my L1 - no doubt this system reaches elderly people on some level I don't pretend to understand.

One nurse said something to me like, "I ain't never seen some of these people move before you started playing."

In all the times I've played at a half a dozen different rest homes (and the Fayetteville V.A. hospital) no one has ever asked me to turn it up - or turn it down.

Last week I got an Ipod running first while I set up the rest of my stuff, and both of the rest home Activities Directors were amazed by the clarity of the sound coming out of the L1.