Using audio gear to help a friend

[Deleted User]

Hello,
I've been working with the daughter of a friend of mine who suffers from misophonia, a condition where certain sounds cause her extreme discomfort. She reacts to the "s" and "ts" sounds in people's speech, which when a certain combination cause her physical pain. She spends a great deal of her day with noise canceling headphones plugged into an laptop to block out these sounds.
I thought of combining a "listening station" with a specific notch filter tuned to the particular frequencies that bother her. Several year ago I built a Velleman kit that had two small condenser microphones and an amplifier to power headphones for my Dad who was having hearing problems. It was battery operated and my wife and I got him a set of good Audio Technica headphones to use. He loved his listening station and would use it for listening to TV and was able to hear everything.
I've built two of these Velleman kits and used Elna capacitors to upgrade the sound (talk about being able to actually hear the effects of capacitors!) quality over the stock caps. Now I've been able to prototype the opamp based twin T notch filter set to provide close to 40dB of attenuation at 4.7kHz (the frequency range she seems most tuned to). Now to combine the filter and listening station.
Cheers, Ken

tonyb

Fabulous idea Ken, and Kudos to you for taking the time to make it happen for her.

[Deleted User]

Thanks, tonyb, I appreciate the kind words.
Here's a photo of the two listening stations, the one on the left is stock and the one on the right is exactly the same except I used Elna brand Silmic II capacitors, same values as input and coupling caps. Polk has generously donated four pair of their sports style and cupping style headphones to the effort (it took them about 4 seconds to approve of the idea). So a person can use the same headphones to hear their environment with two listening stations only difference are the quality of the capacitors in the audio path.
The differences are certainly audible, a significant reduction in high frequency harshness and edginess, but I must say I'm not completely convinced the Elna's are the quality I'm after. I'll try bypassing and maybe double bypassing them for improvements.
My friend's daughter has, on top of misophonia, extraordinarily sensitive hearing so any improvements will be helpful.
Cheers, Ken

txcoastal1

Great job Ken
So if I send you the analytic voice frequencies of my wife when she's pissed at me could you tune me some hearing aids cancelling those frequencies too

[Deleted User]

I felt good about making my mother in law dinner.
You rock!

westmassguy

Hey Ken you're a good guy. As for Caps, you can't do better than Elna Silmic IIs for Electrolytics, I use them extensively. Nichicon does make the Muse, and Muse Gold Series, which are also excellent, Audio Grade Caps. Perhaps Metalized Polypropylenes for the Output Coupling Caps? They'd be very large compared to the Electrolytics however.
Also the 'S' sibilant is normally around 7KHz.
Carbon resistors can also be replaced with Audio Grade PRPs from Sonic Craft

[Deleted User]

He he, I can try, but she might catch on if you put your headphones on when she's mad.
The filter, in theory, can achieve a -50dB reduction at a specific frequency with not much effect on neighboring frequencies. But this requires careful matching of resistor and capacitor values. I ordered multiple resistors and caps and went through a matching process. The values are a doubling of values, so 34k and 17k resistors (which isn't a standard value so two resistors in series) and 2nF and 1nF caps.
Plus the two circuits (listening station and filter) have two different power supplies, single ended and balanced. So, still some work.

[Deleted User]

Hi Westmassguy,
I certainly agree, the Elna caps are good sounding, I'd give them a strong B- or even three chef's hats. My memory of the older Panasonic HFS caps as well as the famous Blackgates are a bit better, with B+ for both. Let me tell you hearing the two different listening stations is a revelation, I think even the most stone-eared statue would admit there's a difference. We did some analysis with the range of most of the problem she's experiencing and 5k seemed the center.
The Velleman kit is MK-136 and sells for around $12.00 not including batteries, but everything else is there. If you know someone who is beginning to have hearing loss it can be a great solution combined with a good pair of headphones. My Dad was reluctant to think of hearing aids and this was a gentle way of letting him hear how something could help.
I actually believe this is going to be an important area of audio, the developing of audiophile quality hearing devices. Most digital hearing aids are $5,000.00 and up and aren't up to our standards. I can see people using vacuum tubes for better sound, mark my words.
Enjoy, Ken

[Deleted User]

In fact if anyone would like to try a listening station, just buy one (eBay and Amazon have them) send it to me and I'll build it, use better caps, and send it to you for free. I can build them pretty easily now. Get some Polk light weight sports style headphones and things can be better.
Plus you can play secret agent and hide behind hedges and listen to your neighbor's conversations.

tonyb

Kenneth Swauger wrote: »

Plus you can play secret agent and hide behind hedges and listen to your neighbor's conversations.

Will it work in Canada ?
I might need therapy though after listening to their conversations.

Curious though, have you tried this nifty device in a rig ? Could help some bright sounding systems with added sibilance for cheap coin....or those suffering tinnitus.

westmassguy

Kenneth Swauger wrote: »

Hi Westmassguy,
I certainly agree, the Elna caps are good sounding, I'd give them a strong B- or even three chef's hats. My memory of the older Panasonic HFS caps as well as the famous Blackgates are a bit better, with B+ for both. Let me tell you hearing the two different listening stations is a revelation

Unfortunately Rubycon lost the license in 2007, and everything out there's been sitting on a shelf for 8 years. The prices some are charging are ridiculous. Not to mention Electrolytics don't fair well sitting around doing nothing. The Panasonic FC and FM Series are also quite good for a general purpose Cap.

F1nut

A most commendable effort Ken.

msg

Ken, wow, so cool, and what a neat project!

[Deleted User]

Thanks, I hope it does some good.

msg

I know nothing of electronics building. are there components that would allow for adjustable frequency blocking? or controlling the amount and width that a frequency is blocked?

[Deleted User]

Sure, that is what a parametric equalizer does, adjusts for increasing or decreasing certain frequencies and varying the width of the neighboring frequencies that are effected. But this filter is extremely deep in the amount of attenuation and is small enough that it could be incorporated into a battery operated handheld device.
Another person who is helping Emma (the person with the condition) is working on a digital solution, a real-time analysis of incoming sounds and a program that adjusts the sound to make it less harmful. Frankly, my approach is clunky in comparison to this one.
The goal is to give Emma enough breathing room in the way her environment is effecting her so that she can develop coping skills to recognize how the sounds are creating defense reactions. Like most treatments the first step is recognizing the condition and then finding way to ease the harm.

msg

I see. Interesting stuff you guys are doing, and cool that you guys are using your powers for good

scottyboy76

I am blown away ken, you will be rewarded, not only for doing the tech work, but also for not dismissing their problems, instead devoting time and effort to help someone.

It may never be noticeable, might even be in the next phase of our existence, but you will be rewarded for giving a damn for one of your fellow living creatures, even though you had no commitment to do so.

god bless,

SAD