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Equalizer circuit needed.

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gary350

Well-Known Member
I need a simple equalizer circuit the ones I found online are not single. 50 years ago I built an equalizer into an amplifier circuit but don't have it anymore it was for a tube amp anyway.

Are equalizes still called equalizes? Transformers are no long called transformers now they are now called inverters.

Years ago an equalize was several band pass filters with a variable resistor on each 1K frequency range. I just want to built a simple equalize not design it myself.

I am building my own hearing aid. I already have a IC amp built that is working good. I have my hearing test that shows my hearing frequency range all I need to do is add the equalize to the little amp circuit then test it.

I bought a set of ear phones for the TV I can actually watch TV now I can hear sounds that I have not heard in 30 years. I was reading online that low Hz travels farther than high Hz. High Hz sounds are lost before they travel across the room from the TV to my ears. Certain Hz ranges need to be 60 to 70 db for me to heat them. When people talk I don't hear certain high freq sounds, S, ph, th, t, f. The word school sounds like ool to me. Some people talk in a frequency range that I do not hear I see there lips move but no sound.

I bought hearing aids they work very well but I still cannot hear everything. With what I have learned I want to experiment to see if I can build a better heating aid. It won't be small but it will be a FUN project to build.
 

MikeMl

Well-Known Member
Most Helpful Member
I see home-stereo equalizers all the time at some local thrift shops for a few $. I would buy one and try it to see if you can improve your ability to process the TV sound with your existing amp and headphones.

I did exactly what you are doing years ago for my father-in-law, who was a WWII Spitfire pilot that flew over 450 combat missions. Needless to say, his hearing was shot when he got into his eighties. At that time, I used an inexpensive Radio Shack equalizer.
 

AnalogKid

Well-Known Member
Most Helpful Member
Tons of equalizers on ebay. If you want to start with a kit:

https://www.canakit.com/5-band-hi-fi-stereo-equalizer-kit-ck145-uk145.html

https://kitaudio.blogspot.com/2012/10/10-band-graphic-equaliser-circuit-with.html

https://rheingoldheavy.com/product/msgeq7-graphic-equalizer-kit/

http://www.soundskulptor.com/uk/eq573.html -- go to technical documents" and find the equalizer. It has the schematic and BOM.

http://analogmetric.com/goods.php?id=1118

Most of these have the schematic online so you can see and adapt.

ak
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Are equalizes still called equalizes? Transformers are no long called transformers now they are now called inverters.
Equalisers are still called that (although they have always been more correctly called 'graphic equalisers'), and transformers are still called transformers, that's never changed (why would it?) - an inverter is a completely different thing.
 

gary350

Well-Known Member
Equalisers are still called that (although they have always been more correctly called 'graphic equalisers'), and transformers are still called transformers, that's never changed (why would it?) - an inverter is a completely different thing.
You probably already know this thing in the picture has a transformer inside a plastic case. It is not called a transformer. 100s of these are available now to power or charge, cell phones, hair clippers, cable box, tooth brush, they are called inverters if you try to buy a replacement. Inverter because it inverts 120 vac to a lower voltage, 50 years ago they were converters because they converted 120 vac to a different voltage. I bought an item at a yard sale with no power supply I went several places asking for a, power supply or transformer I had to show people a picture of what I wanted for them to understand what I wanted. Everyone told me those are called inverters and acted like I was a idiot. They are transformers to ME i know what is inside the plastic case.

I looked at all those links to equalizers, no prices and no order information? 3 or 5 Hz ranges is not enough, my hearing test shows 10 Hz ranges. I kit will be great but no surface mount stuff. I will check ebay again last time I looked there was not much there. I was searching only for equalizer maybe there are better search WORDS?

 
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Nigel Goodwin

Super Moderator
Most Helpful Member
You probably already know this thing in the picture has a transformer inside a plastic case. It is not called a transformer.
It's called a 'switch-mode power supply', and while it has a transformer, it's not a mains frequency one - but even the older ones that did have proper mains transformers inside still weren't called 'transformers' as that's merely one of the components inside, they were simply called 'mains power supplies' or 'mains adaptors', in the USA commonly called 'wall warts' (although that applies to both types).

As far as hearing aids go, the better modern ones already do just what you're looking for, but probably better - I presume it's done via digital processing, and it's set up by a technician when you have it fitted.

If you want to experiment with a decent graphic, try the PA types, such as this:

https://www.amazon.co.uk/BEHRINGER-...coding=UTF8&psc=1&refRID=8WPFAKV0TSEBTY3SC5YS

Many more bands than normal home audio types.
 

audioguru

Well-Known Member
Most Helpful Member
When I turned 69 years old a new hearing aids store opened and offered a free hearing test. My test showed normal for my age severe high frequency hearing loss. They fitted me with hearing aids programmed for my loss and the sounds were awful. Later I went to another hearing aids store for another free test as a second opinion and it showed the same severe high frequency hearing loss. They fitted hearing aids adjusted with only a little high frequency boost and I liked the sound. Two weeks later a little more boost then two more weeks later full boost was set and I liked them so I bought them. They are made by Phonak in Switzerland, model Audeo V.
The hearing aids have been adjusted a few times to make the sound even better and features like compression of loud sounds, noise reduction, extra sensitivity, directionality and muting were added that I select with a button on either hearing aid. They produce absolutely no electronic noise or distortion.

I am an audio guy and I have designed and built many audio equalizers. But there is no way I can design all the features in my tiny hearing aids unless the circuit is in a pretty big box and I set the features separately on each hearing aid. The purchased hearing aids "talk" to each other with Bluetooth so I set only one and they both do the same setting. A telephone is played in both ears. A tiny battery in each one lasts for 10 days. My hearing is now perfect and I forget that I have the hearing aids on until I remove them to sleep. The next morning they sound weird for about 15 seconds until I get used to the better sound.

Maybe you should have your hearing aids adjusted so that you hear better with them. My hearing aids sit behind my ears with a tiny speaker in each ear canal. To have full high frequency boost and to avoid high frequency feedback whistling I needed earmolds made for the little speakers to sit in, maybe that is what you need.

Here are graphs showing normal hearing loss with age:
 

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audioguru

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Most Helpful Member
I was reading online that low Hz travels farther than high Hz. High Hz sounds are lost before they travel across the room from the TV to my ears.
Yes and no. Low frequencies travel for many miles. High frequencies are absorbed by trees, grass and humid air if they travel for many miles. Is your TV many miles away from you?

The international airport is many miles away from me and I hear the low frequencies from the jets taking off away from me. I hear nothing when they takeoff towards me. I hear their high frequencies when they are close to me.
My city is on the edge of a huge lake and there is an island about 1 mile away. When there is a rock concert on the island then the low frequencies can be heard in the city.
 

AnalogKid

Well-Known Member
Most Helpful Member
3 or 5 Hz ranges is not enough, my hearing test shows 10 Hz ranges.
I'm sure it does, but that does not mean that an equalizer with a gazillion 10-Hz adjustment bands is necessary to correct things. For example, if your test showed a steady decrease in sensitivity of 3 dB per octave for everything above 500 Hz, it can be corrected with one opamp and a few R's and C's.

An equalizer with one adjustment per octave would have 11 adjustments. Is this what you have in mind to start with?

Edit: When you said your test shows 10 Hz ranges, does that mean each range is 10 Hz wide (what I responded to ), or that there were a total of 10 ranges across the 20-20,000 Hz spectrum. That would be approx. 1 per octave.

ak
 

audioguru

Well-Known Member
Most Helpful Member
My "normal for my age" high frequency hearing loss is almost a straight diagonal line with a flat part at very high frequencies. It needs double the amount of boost from a tone controls circuit. I think the audiologist adjusted the level of each octave from 250Hz to 16kHz (7 frequency bands) on an audio equalizer. The hearing aids most sensitive setting has the lows and highs reduced.
 

gary350

Well-Known Member
When I turned 69 years old a new hearing aids store opened and offered a free hearing test. My test showed normal for my age severe high frequency hearing loss. They fitted me with hearing aids programmed for my loss and the sounds were awful. Later I went to another hearing aids store for another free test as a second opinion and it showed the same severe high frequency hearing loss. They fitted hearing aids adjusted with only a little high frequency boost and I liked the sound. Two weeks later a little more boost then two more weeks later full boost was set and I liked them so I bought them. They are made by Phonak in Switzerland, model Audeo V.
The hearing aids have been adjusted a few times to make the sound even better and features like compression of loud sounds, noise reduction, extra sensitivity, directionality and muting were added that I select with a button on either hearing aid. They produce absolutely no electronic noise or distortion.

I am an audio guy and I have designed and built many audio equalizers. But there is no way I can design all the features in my tiny hearing aids unless the circuit is in a pretty big box and I set the features separately on each hearing aid. The purchased hearing aids "talk" to each other with Bluetooth so I set only one and they both do the same setting. A telephone is played in both ears. A tiny battery in each one lasts for 10 days. My hearing is now perfect and I forget that I have the hearing aids on until I remove them to sleep. The next morning they sound weird for about 15 seconds until I get used to the better sound.

Maybe you should have your hearing aids adjusted so that you hear better with them. My hearing aids sit behind my ears with a tiny speaker in each ear canal. To have full high frequency boost and to avoid high frequency feedback whistling I needed earmolds made for the little speakers to sit in, maybe that is what you need.

Here are graphs showing normal hearing loss with age:
It sound like we both have the same type hearing aids. Not sure mine is made by Phonak in Switzerland, model Audeo V. I was going in once a month for adjustments. After that I went in every 3 months. My last free appointment is in 5 months. I have 3 programs. If I click the button on 1 hearing aid they both switch to the next program. #1 is for every day talking and activities. If there is lots of noise like a restaurant or driving in the car I can switch to program #2. Program #3 is extra sensitive for TV or being able to hear birds better or the night time sounds like crickets, frogs, bugs. If someone coughs or sneezes it blasts my ear drums out in all 3 programs. I had sensitivity increased and had noise compression set for loud sounds there seems to be a limit to how well that works. It is working very well so far but I can still not hear things I once could hear like an old type wind up clock ticking in another room at the far end of the house or the kitchen water faucet dripping while I am in bed far away or bugs flying around a light bulb after dark or a house fly or misquote unless it is right in my ear. Maybe I am expecting too much. Your right there is no way I can build all those hearing aid options into a small hearing aid amplifier circuit I will probably need a wheel barrel to haul it around. If i put on good ear phones that cover my ears and listen to music I hear sounds I have not heard in 50 years. Good ear phones let me hear things the hearing aids do not hear. I can listen to music and watch TV with no equalizer & no Hz adjustments and hear better than hear aids. This makes me wonder if my tiny IC amp with good ear phones will work as good or better than hearing aids. Most of my hearing problems is from allergies & ear infections all my life. I started having hearing loose when I was about 19 yrs old.

This is my hearing test. Zero is right ear, square is left ear.

 
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audioguru

Well-Known Member
Most Helpful Member
Hi Gary,
I am sorry to see that you are almost completely deaf in one ear and have worse than severe high frequency loss in the other ear.
I first tried Widex brand of hearing aids and their sounds were too shrill but maybe because the boost was fully turned up which shocked me.
The compression of loud sounds on the Phonak brand that I bought works so well that fireworks and dogs barking sound fine. One "automatic" setting is for speech, restaurants and in a mall but in other places I usually use the "music" setting that sounds more natural.

I think good earphones can produce enough power for you to hear better but their very loud sounds might make your deafness worse. The hearing aids people blame deafness getting worse on you getting older.
 
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