Feedback question

[pauldo]

This is pretty far off topic, but given the electronic geniuses that frequent here I figured perhaps I can find an answer to the following dilemma.


My father has Parkinson's and his speech is fading (along with his mind, physical abilities and bathroom control . . .  ).  My brother bought a voice amplifier for my father to use.  It is this one: [size=78%]https://www.onhealthcare.ie/products/voista[/size]
We tried using it and are experiencing feedback issues that are rather unpleasant (even Jimi would cringe).  The setup is with a 'stick' microphone attached to his shirt top about 3" below his chin, pointing up towards his mouth.  The last configuration I tried was attaching the speaker/ amplifier to the backside of his wheelchair, underneath his butt and facing towards his feet.  When the volume is turned up the unit feedsback.  His room is hard floors and walls, various electronics in it (call button, pressure monitor for when he tries to sneak out of bed).  There is a headset unit, but my Mom is convinced that he won't tolerate it on his head.


If volume is set at 6 the unit functions, but not at a level that provides any benefit for the listener.  Turning up beyond that results in feedback.  It was noted that the microphone when attached to my father's chest also picks up my mother speaking who was sitting 6' away . . .


Any ideas as to what can be done to make this better? 

[elwoodblue]

If the microphone your using is omni only,it might not work for your dad's setup.
Especially with the speaker so close.
If you have any EQ, that might be worth playing with...but probably far from ideal.


There are some lavalier microphones that aren't expensive, but should have a better cardioid pattern
for your application.


hope that helps some,

[hammer]

Pauldo:

Sorry to hear about the problems you are experiencing.

I work with persons with physical disabilities both as colleagues here at work and it the community. Many of these people use personal voice amplification systems (PVAS).
From what you have described it would appear you have an omnidirectional mic. Microphones for personal speech amplification systems are available in broad field pick-up (omni-directional) and narrow field pick-up (directional), some with noise canceling features.

Sounds to me that what you need is a directional mike with noise canceling capabilities. We have found that directional mics with noise canceling features, have typically worked a lot better for PVASs because they do a better job increasing the “signal-to-noise ratio” of the voice (pick up more of the voice and less ambient noise) and reduce problems with feedback. Directional, noise-canceling mics are especially good when a person with a weak voice needs to be amplified in an area where there are high levels of ambient noise.  I’m not sure what type of PVAS you are using but I’ve found that you can’t always be sure that there’s a good match between an amplifier and the mic that comes with it.  I’ve seen some quite good PVASs paired with really bad mics.

I can understand someone’s reluctance to wear a headset type mic, which is probably why I’ve seen a lot of people recently using collar mics.  These are bendable mics designed to go around your collar (they can be tucked under the collar so they are pretty much invisible) and point up at your mouth. The mic has no contact with the head or hair and is quite comfortable.  I believe that most of these are directional and some have noise canceling ability. The two companies below both sell that type of mic but you should be able to get one locally (Luminaud: http://www.luminaud.com/voice_amplifiers___microphones & Chatterbox: http://www.chattervox.com/cgi-bin/thatsanorder_LE/ ).

Of course at the high end of the spectrum there’s a company called Voicewave Technology Inc. that has developed a special microphone architecture, electronic signal processor, and an auditory feedback mechanism into their PVAS that basically eliminates feedback, rejects noise, aids in speech production and is claimed to have the sensitivity to pick up signals at or below the threshold of hearing.  The research on this system suggests it does what it claims. Unfortunately, the current price is somewhere in the neighborhood of a new Alembic bass.

[cozmik_cowboy]

Allow me to concur; I have only sound reenforcement, not disability, experience with this type of thing, but before I even looked at the link or read the other posts I thought "Oh - using an omni mic".  Try with a cardiod & I'm betting it solves  the problem.  Well, not the big one obviously; that sucks.

Peter

[pauldo]

Thank you for the thoughtful replies.  We are looking into a directional mic option.

[paulman]

Pauldo, looks like you got some good feedback in this thread in any case    Hope it works out well good luck!