Hearing Assitant

At a Glance

To stay ADA compliant the BHS Auditorium features a Williams Sound hearing assistance system. This is a small low power wideband frequency modulation transmitter that operates in the upper section of the VHF-Low band. Our system is rack mounted and features an external antenna outside of the control booth for optimal coverage. We have the ability to hand out 4 beltpacks that tune into this system. The user can select between either a monaural earbud that fits nicely in their left or right ear or a special necklace device which interface with compatible hearing aids.


The transmitter is a Williams Sound model PPA-T27. It is installed in the top left of rack 1 (control booth left) on a 1U shelf. Its top antenna has been removed and an external antenna has been attached instead. This connects to the back of the unit. 

The transmitter is connected to the Auxiliary processor power system and can be switched on with the red switch at the top of rack 2 (control booth right).

You should never need to touch the unit or make adjustments to the transmitter. DO NOT change the frequency of the transmitter as it has been coordinated with the Bow School District RF plan.


The receivers are Williams Sound model PPA-337. They run on two AA batteries and have a 3.5mm audio jack on top of the unit adjacent to the volume/power switch. The green LED will illuminate when the unit is on. Inside the battery door is a ribbon to remove the two AA batteries, two screw driver adjustable knobs and a 'Channel Search' button. You should never have to touch the knobs but the channel search button may come in handy. We only have four of these units so treat them respectfully.

Earbuds & Induction Loops

Inside the box labeled hearing assistant on the shelf in the control booth are four monaural earbuds and two induction loops. Both of these devices are connected to the 3.5mm audio jack on the receiver units.  The earbud is most likely to be used but the option for induction loops are also available. These are available for users who have a hearing aid that are telephone coil-equipped or feature the T-Switch. This device connects to the receiver, goes around the users neck loosely (this is done by the user NOT technicians), and magnetically transmits the audio signal into the hearing aid when the hearing aid's T-Switch is in the on position. The tension puck on the loop does not need to be tightened for use.