Hearing Assistance in venues

[ramdram]

Curiouser and curiouser, intrigued as I am on this topic what with doing the headset thing, (and on behalf of my mother and in "pursuit of the truth", ** laughs out loud **,) Siemens tech folk tell me, this very morning, that the very small Impact L does indeed have a telecoil and it can be programmed "in" as desired.

 

It occurs to me that this one size fits all solution does work in the majority of cases. My mother, to name but one, has no problems at all nattering on the standard telephone, so perhaps the reasoning, now that is, if a person can hear through the telephone earpiece then they can hear the output of a headset and therefore no need to bother with programming in the telecoil function.

 

(I take your point about small and "small", the in ear types are very small cf even an Impact L and having the physical room for a telecoil.)

 

Ref the type of hearing loss, TR does in fact run a course on this, and other aspects, of hearing disability complete with guest speaker. This is just a part of their staff training package, doubtless not unique in theatreland. The staff are aware of the different hearing issues but very few have experienced them at first hand.

 

However, it may be a moot point about the actual type of hearing loss, affected frequencies, level of attenuation, distortion, tinnitus and so on, simply because "we" can do nothing about it, and, the Senny headphones' frequency response is (to my hearing) flat and as mentioned earlier not in any way hifi. I suppose it could not be anything else given that flat would be optimum for all the different types of hearing loss there are.

 

I speculate further that any signal processing/EQ is accomplished within the 'aid itself, (via the audiologist) which I presume further is expecting "normal" speech on the input mic anyway?

 

So any notions about processing the audio output signal prior to the "delivery" system/ customer interface, IR or loop, may be a waste of time because the audio signal will be processed far more accurately by the 'aids themselves???

 

Fascinating topic and, given some of us will be needing 'aids before too long, of more than passing interest.

[Simon Lewis]

...the very small Impact L does indeed have a telecoil and it can be programmed "in" as desired.

 

Not at all suprised - it is a pretty fundamental technology for those with hearing loss.

 

It occurs to me that this one size fits all solution does work in the majority of cases.

We're back to degrees of hearing loss. For those who have mild HL, an aid could be used in conjunction with a telephone, IR headset etc. Such an aid would have only fairly low gain. Those with more powerful aids might not even be able to put heaphones to their ears without the device going into feedback. Additionally, using a telecoil means all the background noise is cut out (apart from telephone sidetone). This can significantly raise the s/n and for many it is such a vast improvement that they would never consider not using the telecoil.

 

Ref the type of hearing loss, TR does in fact run a course on this, and other aspects, of hearing disability complete with guest speaker. This is just a part of their staff training package, doubtless not unique in theatreland. The staff are aware of the different hearing issues but very few have experienced them at first hand.

 

This is excellent practice. I despair at the "throw technology at the problem" approach taken by many, when it leads to non working, non suitable systems. Disability awareness can be far more helpful than technology.

 

With regards to the actual hearing loss, this may be just 30 or 40dB loss at 4kHz upwards, or it could easily be 60dB loss from 250Hz on a steep slope to 120dB loss at 4kHz. The aid is programmed (within its gain limits) to provide an inverse of the hearing loss curve. Paradoxically, many who have hearing loss also have increased sensitivity to loud sounds (cf loudness recruitment) - one of the reasons why aid manufacturers have introduced sophisticated multiband compression and peak limiters.

 

 

 

I speculate further that any signal processing/EQ is accomplished within the 'aid itself, (via the audiologist) which I presume further is expecting "normal" speech on the input mic anyway?

 

The ALS needs to maximise s/n and keeps a fairly level signal - hence the AGC on AFILS etc. Maximising s/n does (in my book) mean creating a desk mix for the ALS, which will be predominantly speech only. Of course, if the actors aren't miked up, this is problematic, but when I am mixing I treat the loop as another monitor mix, and try to give it as much attention as any other folback or IEM mix.

 

 

Simon

[dbuckley]

This thread has turned out to be a bit of an eye-opener.

 

I've downloaded all the Senny data sheets and manuals and price list, and it seems I need to choose wideband (2 channel) or narrowband (32 channel) and then get a modulator, radiators, receivers and accessories of a matching type. It all looks quite expensive. Two channel should be sufficient.

 

And it seems that a loop is still a decent idea.

 

I need to think about getting the fire alarm integrated into the ALS. Hadn't thought of that. (Adds item to todo list)

 

Dicky mentioned building code compliance: Here in New Zealand, our Code states "G5.3.5 Buildings shall be provided with listening systems which enable enhanced hearing by people with hearing aids" in "Any theatre, cinema, or public hall". So non-optional.

 

The other thing that occurs is that here we are legally entitled to broadcast at the ends of the FM broadcast bands (see here) and so we could use a couple of very low power FM transmitters (eg) and supply low cost radios (like this - $40) to the patrons, along with headphones or loop interfaces.

 

And it seems especially clear that it isn't the technology per se that is the issue, but getting working equipment to a punter and getting a smile on their face.

 

Can of flipping worms!

[Owain]

 

I need to think about getting the fire alarm integrated into the ALS. Hadn't thought of that. (Adds item to todo list)

 

....

The other thing that occurs is that here we are legally entitled to broadcast at the ends of the FM broadcast bands (see here) and so we could use a couple of very low power FM transmitters (eg) and supply low cost radios (like this - $40) to the patrons, along with headphones or loop interfaces.

 

Using FM broadcasting - would that affect your licensing/rights as you might be classed as radio broadcasting the production? And you might find that the receiver radios are more likely to 'walk'.

 

 

[dbuckley]

Licencing and rights... an interesting question. I don't think so because (a) hearing loops are broadcasty anyway and audible well outside of most venues, (b) the FM level will be controlled, and © there seems no interest in what happens to audio in digital cinema in terms of protection, only picture. The picture stream is encrypted to hell and back, whereas sixteen channels of audio (eight AES/EBU two channel streams) just fall out of a D15 connector of the IMB.

 

Just FYI, with series one digital cinema (which is what everyone currently uses), the movie arrives as a big encrypted compressed file, and you ingest the file into the media server. You need to have a key to decrypt the file, which matches a specific movie, and matches the specific "IMB" (Integrated Media Block) which is the thing in the media server that decrypts the movie. The key also controls when you can play the movie. So you have the movie file, you have a key, the IMB will decrypt and decompress the movie in real time, and then re-encrypts it using a key that has been negotiated with a specific projector, the image data then going from the IMB to the projector encrypted. The projector then decrypts the signal and displays the picture.

 

The projector and the IMB are "married", and if you open the projector, a divorce takes place. The remarriage requires the presence of a trusted agent of the movie companies.

 

The IMB is also protected, and if you tool with it it does a mission impossible.

[Owain]

Licencing and rights... an interesting question. I don't think so because (a) hearing loops are broadcasty anyway and audible well outside of most venues, (b) the FM level will be controlled, and © there seems no interest in what happens to audio in digital cinema in terms of protection, only picture. The picture stream is encrypted to hell and back, whereas sixteen channels of audio (eight AES/EBU two channel streams) just fall out of a D15 connector of the IMB

 

I was thinking more of musical/theatrical productions rather than cinema but much the same applies.

 

 

I don't think audio-frequency induction loops count as broadcasting because they're not *radio* broadcasting. Depending on the antenna system used you might get a similar restricted coverage of FM.

 

One other thing to consider may be that if an audio-frequency loop is in use in the auditorium that may affect the usefulness of a loop at the ticket counter etc, or vice-versa.

 

 

[dbuckley]

One other thing to consider may be that if an audio-frequency loop is in use in the auditorium that may affect the usefulness of a loop at the ticket counter etc, or vice-versa.

 

Something else for the todo list...

[Bryson]

Back in Croydon, the (sadly now-closed) David Lean Cinema had an induction loop fitted originally...except it was directly below the council chamber, which also had a loop fitted. So frequently people in the cinema would have the audio from a council meeting instead, or, worse, those trying to listen to a council meeting would get whatever movie was on!

 

Replaced with infrared quite sharpish once we realised what was happening!

[Simon Lewis]

Counter type loop systems effectively rely on the user picking up the magnetic field radiated outside the coil of wire fixed horizontally or vertically to the counter's structure. Since the loop size and loop current is relatively small the area covered is also quite small - as you would want.

Perimeter loops have the user sat inside the coil, but the signal can be picked up upto several times the loop width away. There are techniques to reduce the amount of loop spill, but most require special loop layouts or driving techniques, and are not usually a simple fix.

 

I would not expect too much problem with a perimeter loop and a counter loop, unless they were in very close proximity. However, two perimter loops side by side (e.g multiscreen cinema) acn give rise to significant crosstalk and loss of privacy. This isn't very good whan the family is watching Bambi, and the film next door is The Deer Hunter...

[Owain]

Back in Croydon, the (sadly now-closed) David Lean Cinema had an induction loop fitted originally...except it was directly below the council chamber, which also had a loop fitted. So frequently people in the cinema would have the audio from a council meeting instead, or, worse, those trying to listen to a council meeting would get whatever movie was on!

 

Replaced with infrared quite sharpish once we realised what was happening!

 

 

 

 

I can wander through the shopping centre and listen in to people discussing their rent payments in the adjacent council offices. This is picking up a mix of small meeting room perimeter and counter loops. The council don't have any BS design and commisionning certificates for the loops but I expect they still paid a lot of money for them.

 

 

 

[ramdram]

Oh the irony! The irony!

 

Did the headsets for Phantom in Plymouth the other evening. Only one taker, who was fully au fait with our system.

 

Come the interval and he's returned it. Doesn't want a replacement. I test it and it works satis.

 

Must be the "normal" level for the show is more than enough even for the hard of hearing, ** laughs out loud **. definitely not a "quiet" show.

 

(For the technophiles, the scenery/set stole the show, for me anyway. The centre piece on stage was "interesting" in the novelty techno dept and must must be fairly complex operation wise. The chandelier was pure indulgence mind but looked "brilliant"...

 

Never seen so many bods wondering around in tee shirts, dripping with comms kit.)