[SML] infrared hearing systems

[Stephen Litterst]

On 11/24/14 10:44 AM, Garry Brown via Stagecraft wrote:
>    I’ve been asked to gather information on infrared hearing systems for
> our two theatres. So far, I’ve done a couple of searches on said systems
> to determine what exactly we might need and a ballpark cost estimate,
> but I really don’t know anything about them beyond the basics of a feed
> of some sort, an amp/router, and headset receivers.

First off, is there a reason you're going the infrared route?  There are 
variety of assisted listening system technology, ranging from IR, to RF 
to induction loop.  Depending on your needs, one of the other 
technologies may better suit your application.

In brief:

Infrared:  requires every seat to be in view of the IR emitter, and for 
the patrons' devices to have an unobstructed line-of-sight to the 
emitter.  For large theatres, this may require installing multiple emitters.

Radio Frequence (RF):  Essentially a low-power FM radio station.  An 
antenna from the transmitter broadcasts the signal to the patrons' 
devices.  Line-of-sight is not an issue, but building consruction or 
poor antenna placement can create dead zones.

Induction Loop:  A copper conductor is looped around the audience, 
allowing patrons with the proper hearing aids to tune directly into the 
feed (stand-alone receivers are available as well.)  Can be 
cost-prohibitive to retrofit into an older building.

I think the most important part of any system is the quality of the feed 
into it.  I know of a theatre that spent in excess of $20k to replace 
their RF system with an induction loop, only to find the problem wasn't 
the AL system, but the feed to it.  They then spent further $$ to 
upgrade the microphones which then made both systems sound much better. 
  It doesn't matter how you deliver the sound, if you're not capturing 
clean sound to begin with.

Steve L.


-- 
Stephen Litterst            Technical Operations Supervisor
litterst at udel.edu           Mitchell Hall
302/831-0601                University of Delaware