Update #1 January 27, 2011: Please scroll halfway down to red portion of the text
The project of rating two new digital FM systems, the Bellman & Symfon Audio Domino (PDF w/specs) ($495 street) and the Etymotic Research Companion (specs; how it works) system ($699 street w/three transmitters and ER-6i isolator earphones) is turning out to be a three-part series of articles, taking much more time than I expected… And I am soliciting comments on any FM system about your user, parent, teacher or hearing healthcare professional experiences — Good .AND. Bad. Please post your experiences in either the Comment section below, or email them to me at Dan@Snip.Net
The first of the three will be how and why FM — When it’s done properly — is a tremendous help to the hearing impaired and others, from infants & toddlers receiving auditory therapy, to children (including those with cognitive impairments), to high school & college students in large classrooms & lectures, to adults on the job, and in noisy social situations, to the elderly watching TV.
Most of the first article in this series will center upon the discussion on these 4 pages in Jamie Berke’s About.Com Deafness Forum. [And Yes, the story about the beer is true!]
The second article in the series will deal with the situation when FM is .NOT. done properly, and interference or other issues result. Phonak’s FM system appears to be a serial offender, but there are other culprits. This article will go into the techno-details on things like multipath distortion vs dropouts, transmitter power, and other things a computer geek or Ham Radio operator would understand… So the challenge is to make it readable for the average parent.
The third article in the series will be test results from these three systems:
§ The Bellman & Symfon Audio Domino (PDF w/specs) ($495 as tested with earphones) is a flexible single transmitter system, with excellent audio quality, decent range, and highly directional microphones on both the transmitter & receiver;
§ The Etymotic Research Companion (specs; how it works) system ($699 as tested with three transmitters and ER-6i isolator earphones) ships with either one or three transmitters, and is the only system (besides the Phonak DynaMic extension to the troublesome Inspiro) that provides many-to-one capability;
§ The Comfort Audio Contego ($795 as tested w/neckloop) is a single encrypted transmitter system; and was screened by the author at the HLAA Convention in Milwaukee.
Although they have differences, the Bellman Audio Domino Classic costs $200 less, and performs as well as the Comfort Contego. While the Contego has a zoom mic, the Audio Domino Classic has a tone control on the receiver, and also when stereo is input into the transmitter jack, the system switches to digital stereo (more on this in a moment).
Previously, A.U. raised a point about the 40ms latency of the Audio Domino vs 10ms delay in the Contego (vs. no latency with analog!) and how it can interfere with lipreading cues. [Note:In googling Comfort Contego specifications there is no mention of latency.] From personal experience, I haven’t noticed any latency issues; but more importantly, if either system is used with a TV, it is important to note that with the shift from NTSC to HDTV the lead/lag for the separate AC3 and MPEG audio streams can be up to 150mSec (and in practice is often much higher), so the (supposed) 30ms delta between the two doesn’t seem to be a factor.
Now, let’s say your patient wants a zoom mic on the transmitter & receiver: With the Contego, the user has to walk over and manually switch the transmitter. But, remember when I said above that the Bellman Audio Domino Classic transmits in digital stereo? Well, so does the Audio Domino Pro… But also, the Pro version does something Really Clever: The audio from the omni mic rides on the left channel simultaneously with the audio from the zoom mic! This way, the user need only push the button on the receiver to “zoom” the transmitter, saving endless user fiddling.
My friend Sarah, who blogs on her Speak Up Librarian website received upon my recommendation the Audio Domino Pro from her employer to use at work. She wrote two extensive first-person reviews here and here that are worth reading.
Finally, I welcome everyone’s own observations of FM ALD’s, whether good or bad; clinician or user, on The Hearing Blog’s article covering all things FM.
Update #1: January 27, 2011 @3:45PM EST