Author Options:

Lost larynx to cancer, now use electronic voice, battery powered. Feel it could be improved - refine electronics? Answered

After losing my larynx to cancer last year, i now use an "electro larynx" (http://www.griffinlab.com/Products/TruTone-Electrolarynx.html) a great device which translates the vibrations my mouth makes when i "speak" with a rubber tube (the exact same as the one my dentist uses to extract excess saliva) in my mouth. The vibrations are transmitted somehow to a vibrating rubber disc inside a handheld device. There are a few other bits too technical for me to understand and describe, but the end result is an electrical voice a bit like Stephen Hawking's.

The machine has a plastic disc built into the lid, held in place by a rubber gasket round the edge, which is made to be pressed against the underneath of the chin or the upper neck. When the laryngectomee speaks,  the vibrations of the throat cause the disc to vibrate, which in turn oscillates a small plastic rod underneath the centre of the disc. This rod runs through the centre of a rubber disc, which is vibrating at high speed because the laryngectomee also presses a button when (s)he speaks, causing it to do so. The vibrations somehow pick up the voice vibrations and turn it into electronic speech. Underneath the rubber disc is a some sort of coil of copper wire almost the full diameter of the machine, and there are 2 pieces of wire soldered into place , too. I don't have a clue about electronics or really anything, so i'm hoping someone out there can make sense of this mumbo jumbo. I'm sure that having a look at the website will help. As I said, normally the device is pressed under the chin, but my neck and chin are rock hard from having loads of surgery, so they don't vibrate - the clever people came up with the solution for people like me: a thick rubber cap fits over the top of the device with a hole through the middle, 5mm maybe. into that is inserted the piece of dentist tube i mentioned earlier. this somehow does the trick, and once more i have the miracle of speech!
Now, as I said, this machine is amazing, and certainly beats having to write everything down. trouble is, it has a volume control wheel which is so difficult to get into the right spot, it goes from way too loud to almost inaudible. Now, having seen some of the stuff you guys come up with on here, and the apparently relative simplicity of the machine, i was wondering if anyone could come up with a solution to my quandry....Yours, speechless, Dave.


Hey David,

I'm tinkering on somethin for this.

I'll post updates. are you still lookin at this site?

Yeah, still keeping a check on the answers! Some odd them fit a bit technical for me, and the idea of putting tape on the columns dial doesn't work because springs I need different volumes for different levels of Background noise. But live to hear all the skill and knowledge pouring forth :) I suppose really I'm so spoilt with digital devices where you can change volumes with an up and down volume button, by very small degrees, and know what number you need to turn it to for each particular situation. 3 for sitting quietly with my wife, 5 for small groups of friends talking, 8 for busy gatherings and walking by the roadside etc. I probably didn't make myself clear enough : the morphine and radiotherapy have ruined me off some of my clarity of expression. :)

i put tape on stuff I don't want to come on in my bag. Just peel it back to turn it on. Sometimes, building up walls around a dial prevents inadvertent change s. Putting it in a deeper well, that is.

In a post I wrote here last week, I made the claim that a device the music community calls, "talkbox", and the device the medical community calls, "electrolarynx" or "artificial larynx".

I still believe this claim to be true, but I want to address one of the sort of obvious differences seen in the implementation of a typical, homemade, talkbox, versus a typical, professionally made, electrolarynx.

Specifically, there seems to be huge difference in physical volume of the transducer.

The homemade talkboxes seem to have transducers with large volume, like the size of like a basketball or soccer ball (~20 cm diammeter), and this volume is taken up by a off-the-shelf speaker, plus a big air-filled acoustic chamber connected to a narrow tube on one end.

In contrast, a typical, professionally made, electrolarynx has a transducer, about the same volume as a golf ball (~2 cm diammeter).

So, sort of a natural question is, "How are the pros doing it?" How do they make their transducer so compact?

I think the answer lies in the fact that a off-the-shelf speaker, is designed for pushing against air. Moreover, the usual method, in a homemade talkbox, for coupling energy out of the speaker, is to just let the speaker push against air in the usual way, except the air is in a air big chamber, about the same physical volume as the speaker, with that chamber getting narrow in one place, where it connects to a narrow tube, also filled with air, that carries the sound energy to the mouth of the user. Essentially the whole path, for conducting sound energy, is made out of air.

In contrast, the transducer of the professionally made electrolarynx, is made to push directly against neck flesh, a (sort of) solid sound conducting medium. I am guessing the armature, the part that moves, is pushing against flesh (and flesh pushing against it) with more force, and over a smaller area, than for a typical air pushing armature, like a paper speaker cone.

What does this mean for the construction of the transducer? I am going to guess it means more turns of wire, to get more N*I*l*B, Lorentz force,
pushing against the wire. Also the actuator is probably stiffer, and stronger. Also it pushes on a smaller area.

The Griffin patents I linked to earlier,
did not give a lot of detail about the actual construction of the transducer. So that was something I was wondering about.

At first I was imagining that maybe it was something like a pinball kicking solenoid. The armature for a pinball solenoid is certainly stiff. It is essentially just a cylindrical piece of steel.

Although since then, I have found some other electrolarynx patents that show more details about the transducer, and the armature for these looks like the usual ring shaped, moving voice coil, like in a typical air pushing speaker, except (I am speculating) this ring shaped armature is likely stiffer and stronger, maybe has more turns of wire, than the kind found in a typical air pushing speaker.


I've been looking at this thread, and the places it links to, and various patents, for the past day or so, because this is just a fascinating topic.

I mean I do feel bad for you, because you had to get your larynx cut out, but at the same time, this story has given me the opportunity to learn more about the mechanics of vocalization, and also the opportunity to be thankful I still have my larynx.

Although, I guess I don't use it much when playing on the internet, and typing at people on the forums and stuff... except when I LOL. Ha!

Anyway, I've got a few suggestions for you, and my first suggestion is one that you're probably not going to like.

To me, your complaint about the volume control wheel, it sounds to me like the proverbial musician blaming his instrument.

It is a complaint I frequently hear from people who do not understand technology; i.e. that there is something wrong with the device.

So, my first suggestion, is to seriously consider the possibility that the volume wheel is not moving by itself. Putting tape on the wheel might help, if only to convince yourself the wheel is truly not changing its position, or if you really are moving it through some kind of fat finger fumbling.

Also consider the possibility that the amplitude (volume) of the sound depends strongly on the exact mechanical path conducting sound the into your head. I mean, I suspect it is going to depend on, where you have the straw placed in your mouth, and maybe even how firmly you have it placed there, if part of the sound conduction is solid-to-solid, like from the straw to your teeth.

As an example of this, of sound conduction depending on the firmness of the contact, look at the demo video Toga_Dan linked to yesterday, at around 1m+25s to 1m+55s. I'll relink it here:

The effectiveness of the sound conduction seems to depend strongly on how firmly Cliff is pushing this gizmo against his neck, as he demonstrates.

Anyway, it is not far-fetched to imagine there could be an analogous kind of attenuation (decrease in volume) when using the straw-in-mouth method, depending on exactly how the straw is held in the mouth.

So I guess I am asking you consider your technique, and to try to improve it.

Most people, myself included, hate advice like that, but I think it is maybe worth considering.

By the way, the guy the demo video, named Cliff, I suspect, is the same Clifford J. Griffin mentioned, in the inventor name, and assignee name, fields in the patents I linked to yesterday.

So that's the guy who designed, patented, built a company upon, the device you consider to be flawed.

Does he seem like a jerk? Like someone who doesn't try very hard?

Well, that's not the impression I get.

Although, if I were to consider a truly unfair advantage that has possibly contributed to Cliff's success, that advantage would be the extent to which he has aligned himself with the dark forces of the health (sickness) insurance business.

I mean, I am sure that Cliff's product is some sort of officially recognized, approved, sanctioned, medical device. Thus making it easier for insurance companies to direct money for to pay for his product specifically, versus his competitors, if he has any, and when the insurance is paying for a large fraction of the price, for many of their customers, there is absolutely no incentive to make the device affordable.

Which brings me to my next point. If you want to take apart this product, and modify it, e.g. by replacing the volume control wheel, technically a potentiometer,
that is maybe going to be expensive, if you break your device while trying to improve it. Or that is the impression I get from searching for used a TruTone(r) electrolarnyx on eBay. The median prices seem to be circa 500 USD, with the absolute cheapest offer, for a used one, at around 200 USD.

To me this pricing seems crazy, for s device that is about as technically sophisticated as an electric toothbrush!

Perhaps an electric toothbrush could be used as an electrolarynx? Something to try perhaps. I've seen low-end electric vibrating toothbrushes priced as low as 1 USD.

Well, maybe that comparison is unfair. I've read through patents
5812681 and 6252966, and some of the parts are a little bit rare, e.g. the pressure controlled resistor, under the push button, used for tone emphasis. (This is a part different from the volume adjust wheel, which I am sure is a common potentiometer.) Also the transducer (the part that moves, vibrates) is custom, and I am not sure exactly how it works, as a voice coil, or as a solenoid. It would be a little tricky to build if you tried to make that part from scratch, like from magnet wire, and magnets, and metal cylinders.

However, there are are alternative strategies that can get you to almost the same device.

The first thing to realize, is that different people are calling this thing different names.

The medical community calls this device, "electrolarynx", "artificial larynx", or "speech aid". You probably already know these names.

The music community calls similar devices, "sonovox", and, "talkbox", and homemade versions of these will tend to be inexpensive, even after including the labor required to build them.

I don't know if you followed all the links Rickharris pointed to, in his answer, but he to some pages that linked to good pages, in particular this one, titled, "Labor of Computer Love: Two Decades of Talkbox Attempts".


This page suffers from some serious TLDR. In fairness, sometimes my writing suffers from the same. On that page, you kind have to scroll down, a lot, until you see, "STEP 1", "STEP 2", etc, and the end result, pictured in steps 7 and 8, is pleasing.

Basically it is a big woofer-type, loudspeaker, taped to a plastic mixing bowl, buried under a bunch of blankets, with a piece of clear vinyl tubing, attached on one end to the plastic mixing bowl, and with the other end inserted into the mouth of the author, as shown in the last picture.

Actually, those pics are inspiring enough, that I am going to repost them here, attached to my post. These pics will be at the very bottom of this post.

Obviously, Mister Paranorm's implementation is a little bulkier than the fist-sized TruTone(r), but he seems pleased with the results.

Also note, Paranorm is using a keyboard, or some kind of musical instrument, to drive the speaker, and there are of course other more compact ways generate this drive signal, which like they say in the patents, are well understood to those skilled in the art.

For everyone not skilled in the art, I guess that's what the Instructables let's make search is for.


Like, Rickharris said in his answer, "everything is learnable you just need motivation:-)"

Final worthwhile link, perhaps for inspiration or motivation, is this one of Stevie Wonder performing "Close to You", via keyboard driven talkbox. This video should start at 1m+10s, because everything before that is preamble.


Would you share any patent #s with us?

I'd like to see a cutaway line diagram. 1 pic is worth 10,000 words.

uspto.gov can be valuable for searching such pics.

How much did this do-hickey cost? The best way for me to appraise a device is to dissasemble it. unfortunately, this is _usually_ technique i apply to thrift store stuff, and other stuff I wouldn't mind (potentially) messing up.

This page,


has a kind of search engine, for parametrically searching through US patents and patent applications.

As sort of a guess, I tried the string, "abst/larynx and an/griffin", and this returned exactly two patents:

5812681, "Artificial larynx with frequency control", and


6252966, "Artificial larynx"


I have not actaully read these patents yet, and I do not know for sure if this is the same company, Griffin Laboratories, but it probably is.

I'll look at that from a real computer later. But if DavidK shares patent #s, it'll make it easy.

Ok I don't have any experience of these instruments but some years ago I spent several months trying to make an artificial larynx - just for fun. Although I had some success it never amounted to what I imagined as the movements of the mouth/oral cavity are very subtle.

I think you problem is that the machines generally produce a constant tone whereas your voice varies it's tone according to your needs. this makes the robotic voice your getting.

You can see below a tone generator that can vary the tone.

All the instrument does is produce an audio vibration that transmits into you neck so your oral cavity can shape it into words.

There are lots of ways of producing such vibrations, a simple 555 timer driving a piezo transducer should work (untried).


I would think you could use a sound generator and the sonovox type of modulator so you could provide the varying tone with one hand whilst talking - It would need some practice though.



your lack of electronics experience will hamper you but everything is learnable you just need motivation:-)

Or someone who lives near you that already know the electronics bit.

You could try asking Ben Heck if it is a project he would be interested in.


If your main concern is volume control, then Toga Dan's note about taping the control is the easiest thing to do.

Are there other improvements you would desire?

"it has a volume control wheel which is so difficult to get into the right spot, it goes from way too loud to almost inaudible."

I end up using tape on my electronics when i want to find the sweet spot. Find the ideal volume, then put tape on it. It is like a safety cover on a switch. Can't accidentally adjust it. I use blue painters tape so it doesn't leave goo.

Is this an indication of the best sound from this device?

About 8 minute mark shows intonation.