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Author Topic: External audio manipulation for hearing impared hams  (Read 2490 times)
K8AXW
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Posts: 3322




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« on: December 17, 2010, 09:31:07 AM »

Greetings All:

I am 75 years old and had to give up operating SSB for several years because of hearing degeneration.  I finally found a solution to this problem by building a device called "The Audio Enhancer" which was featured in a past issue of QST. It took the monaural RX output, split it into two channels with each channel having two roofing filters and an audio amplifier.  This device fed a pair of stereo headphones.

Since then I have been able to enjoy SSB phone contacts and ham radio once again has become a source of enjoyment.  (Prior to the "Enhancer," it was necessary to restrict my operation to CW where I could manipulate the gain and the frequency of the received signal)

Now, with my hearing becoming even worse I find myself being restriced to fewer SSB contacts.

My question, after all of this "preamble" is; is it feasible to buy a small, inexpensive (read CHEAP) audio mixer board and amplifier to manipulate the frequencies of the received audio?

I operated a 24 channel mixer board for my church until my hearing became so bad that I had to give it up.  During the time I could operate it, I could add/attenuate the LOWs/MIDs/HIGH frequencies to make the final output sound better. (For example, women's high frequency voices could be attenuated some and bass frequencies boosted and the result was a very understandable product.

If anyone has had experience doing this very thing with ham radio, I would like to hear from you and what you used.

73

Al - K8AXW

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W3LK
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Posts: 5643




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« Reply #1 on: December 17, 2010, 04:52:27 PM »

It's not in the cheap category, but this may be what you are looking for:

http://www.mfjenterprises.com/Product.php?productid=MFJ-618

I'm sorry to read of your hearing loss problems.
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K8AXW
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Posts: 3322




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« Reply #2 on: December 17, 2010, 07:38:46 PM »

W3LK:

Many thanks for reminding me of the MFJ-618!  I had completely forgotten about that piece of gear!  It sounds like what I need although the cost is a problem that will take some time to solve.  In the meantime, I'll continue to search for or solicit other suggestions on a similar piece of gear like a 2 or 4ch mixer board.  I've been searching eBay but haven't yet found anything that I'm willing to gamble on.

I do have a 100w audio amplifier so really need a mixer to condition the audio before applying it to the amp and either speakers or stereo headphones.

Thank you for your condolences.  This is a problem I have been doing battle with for several years and losing!  This is the price paid for 40 years working in a power plant.

73 and again TY.

Al - K8AXW
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W3LK
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« Reply #3 on: December 18, 2010, 07:45:26 AM »

There are a lot of relatively inexpensive mixer boards with multiple equalization controls, but the names escape me at the moment - sorry. Check your local music/guitar shops. Used equipment is almost always available a reasonable prices.

A 100w amp is WAY overkill, especially with headphones. With a speaker 10w is more than sufficient and with headphones more than 5w will be excessive. The key factor is the distortion at rated output. You want it as low as possible. The 3w amp in my radio will drive my Heil headset to painful levels long before I get the volume to max.

Just be careful; you don't want to exacerbate the problem.
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K9YLI
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« Reply #4 on: December 18, 2010, 08:08:08 AM »

check MCM electronics  on the web.   I think they have a small unit  for under  50 bucks.

they have alot of professional  audio  and sume  cheaper for the home stuff too.

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K8AXW
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« Reply #5 on: December 18, 2010, 09:18:01 PM »

OK.... well the 100W amplifier is wrapped in plastic and needs to be used..... and would drive a couple speakers FB.  My late mother used it with bookshelf speakers in order to hear the TV.  Was figuring on doing the same thing.  As for headphones, I'm hoping I can cut that down quite a bit, naturally.  If not, the it would be "Plan B."

R on MCM electronics.  Will check them out.  Thanks guys.

73

Al - K8AXW
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STAYVERTICAL
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« Reply #6 on: December 19, 2010, 02:22:03 AM »

If you have a PC or laptop, one solution, which would be free, is to use a DSP program which manipulates the audio on the microphone or line input of the PC.
I use one call BruniFilt by Berndt Reiser.
It seems to be freeware and works very well indeed.
I use it as a cw filtering program and also for SSB noise reduction.
It also has a facility in which you can increase or decrease the pitch of the incoming audio by any increment you wish, without touching
the transceiver dial.
It also has all sorts of nice DSP filters for reducing noise and such.
I use a signalink USB interface and use this as the input and the standard soundcard (onboard) as the output device.
Very useful for radios without good DSP and works a treat.
Otherwise, there are quite a few free audio DSP programs around which will work better than any interface you could build and are free.

Hope this helps (I have the same problem with hearing - too many years in noisy computer rooms!).


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K9YLI
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« Reply #7 on: December 19, 2010, 08:21:17 AM »

100 watts audio.. wow..   
from  Sony dictation equipment lituriture,,

rule of thumb  for  PA system  is     25 watts per  1000 people..

a really  big  church  holds about  600 to 700 people..

I dont have a hearing problem  but i do run my  audio  to a  10 watt 
PA  so i have extra  output and  more importantly     tone control..
and      8 inch speaker....

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K8AXW
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Posts: 3322




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« Reply #8 on: December 19, 2010, 11:25:29 AM »

Well, here's the skinny on the 100W amp.  My idiot brother bought the amplifier and two bookshelf speakers and then asked me to "hook 'em up for mom."  Well I did and everything worked for a year or two and then one day mom (age 91 at the time) made a mistake and blew both speakers. (Hellova wonder she didn't blow both hearing aids as well!")

Then my idiot brother bought two new speakers and some other kind of amplifier and told me once again "to hook 'em up."  I did and all was well.

In the meantime, I have this amplifer with no controls except an on/off button.  I can't throw it in the garbage so I thought I could ease a little audio into it from a mixer board and use it for speakers or even headphones, even if I had to use an antenuator.  However, the headphone part can be changed to using the mixer board "Studio Monitor" function.

I was hoping someone had built a two or three channel mixer using op-amps and pots that oculd be built for cheap could direct me to a circuit.  It was suggested this morning that I check a particular audio equipment outlet for used boards or even a pawn shop.  I'll be doing just that along with trying to figure out how to pay for on of the MFJ-618 enhancers in case these don't pan out. 

This thread is still open boys and girls and I'm still open for ideas.

73


Al - K8AXW
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AD6KA
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Posts: 2228




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« Reply #9 on: December 19, 2010, 03:04:29 PM »

Sell the 100 watt stereo amp, for which you really have no need,
and put those funds toward the MFJ device, which
is designed exactly for hams with hearing pitch issues.

A consult with an board certified audiologist would be
a good idea. He/she can give you a graph which
shows exactly which audio frequencies are impaired.

NOTE: Hearing aid salesmen are NOT board certified audiologists,
though they may have some modern looking equipment in their office,
along with fancy certificates on the wall.


73, Ken  AD6KA
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K8AXW
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Posts: 3322




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« Reply #10 on: December 19, 2010, 04:41:35 PM »

Hi Ken,

Will give the thought about selling the amp due consideration. 

As for the "hearing aid salesmen not being certified audiologists", you're absolutely correct.  This is why I refuse to talk to a "sales person" after seeing a ENT doctor.  However, the one person that I go to for my hearing aids and hearing aid adjustments (which must be done with a computer) is legit.  We have in depth discussions about hearing problems,frequencies, etc. When I get mine adjusted I watch the computer screen as he raises or lowers each band of frequencies.  I can actually hear the changes that he makes.  He also knows my background in electronics and so far he hasn't tried to BS me.

Now the problem with hearing aids and SSB.  When listening to a SSB signal, each one has characteristics generated by the microphone, speech processing and speech compression.  (Compression is no doubt the most abused processing that a transceiver has) Consequently, some signals are extremely narrow and high pitched which drives hearing aids crazy.  It's next to impossible to tune this characteristic out. 

I am hoping to either buy or build a mixer board which will cut these high frequencies and boost the mid or low frequencies that are there to create a band of audio frequencies that I can understand. The MFJ-618 sounds exaclty what I need but sure would like to do this with less money.  Fixed income, you know!

Thank you for your reply and intelligent opinions.

73

Al - K8AXW
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W5FYI
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Posts: 1043




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« Reply #11 on: December 19, 2010, 08:23:01 PM »

You might want to investigate voice-to-text software, and "read" the other stations' comments on your computer monitor--in complete silence!  I don't know how these programs work with the limited voice bandwidth of the ham bands, or with mistuned SSB signals, but maybe someone else has experience there. I understand that DragonVoice is one such speech-to-text program, and I'm currently investigating Google's voice-to-text system in its popular Google Voice program. GL
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K8AXW
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Posts: 3322




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« Reply #12 on: December 20, 2010, 08:49:34 AM »

I'm not read for the computer "reader" software yet. At the present time I am enjoying working a lot of SSB DX, I just have to pick and choose who I call.  If I call CQ and get several calls, then I have a major problem.  But I work around that and thanks to the patience of most callers, I finally get them sorted out. One thing I've learned in my 75 years is to be prepared.  If I see a trend then I prepare for eventualities.  Most do this even if it's subconciously. Prior to the Audio Enhancer that I built I was limited to CW.  I see the day when I wil eventually be restriced to CW once again.  That's assuming I outlive my ears.  HI.

Al - K8AXW
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NA0AA
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Posts: 1043




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« Reply #13 on: December 21, 2010, 08:23:01 AM »

Sounds to me [no pun intended] like what you need to find is one of those 10 or 12 channel component EQ units that were wildly popular in the 70's and 80's - you can put that to the input of your amplifier and tailor the sound to your needs.

I see them at gargage sales and second hand stores regularly - should be plenty cheap enough, if the pots are noisy, de-oxit aught to clean 'em up.

Not home brew, but will work with your power amplifer.

Good luck - I have some high-end losses myself.
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KG4YMC
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Posts: 297




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« Reply #14 on: January 04, 2011, 04:44:47 PM »

 I hope this may help. I am 57 and have a hearing in both ears. If you can find a certified audiologist, or even if there is a collage near you , they may have a speech and hearing center were they can test your hearing and give you a chart and readout . I had this done at f.s. u. before going to Mircle ear.  I  really am not promoting one brand , the important thing is that "ann" my audiologist at Mircle ear is honest , board certified and won't sell me somthing I don't need or sell you less than what you need and then try to talk you up to the next model which is all a hearing aid salesman or person will do. A good audiologist and hearing aid center, they will show you a red line on the computer  then , can show you the freq you need to amplify. I am the behind the ear model on the  right ear, other ear is about shot , but you really ( I do anyhow) need to to hear what direction sound is comeing from .  new aids are not cheap. about l500. a piece but worth it . Lady says they figure about seven years  service life. I looked up the esteem info . I f you got 30 grand or more to spend, plus extra for mri  to see if they can fit it , my audilogist says way to much overkill for me ..   anway didnn't mean to get off suject . I find that with  my radio sometimes I hear better with interanal radio speaker when radio is in self. Also try turning down rf and aduio adjustments. I usually made mistake of trying to make things  louder. That is what old hearing aids used to do I  think , you are on right track if can just boost freq you need .  Dont waste money on tv ears or  all freq amps  type hearing aids . another sugest ion. somtimes companys advetize for test subjects to try new hearing tec and can mabey get hearing aids cheaper , also when I was getting my behind the ear model, ann, let me use demo with earpieces they had until  got molded piece back and new one .  Again find repultable  preferably chirstian audiologist , check certs and go from thre good luck kg4ymc    hope this helps some .    terrry . also use hearing protection for shooting , chainsaws ect ...   Oh your moms hearing aids probably just ' shut down " when they got to much sound comeing in , they just go :" you donn''t need me anymore "  audilogist says .
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