I love the signature Roger Troutman talkbox sound. To me, it's a punchy dose of nostalgia and a such a silky lead sound that I want to be able to harness it for myself. After going on a youtube binge one day and listening to most of his discography, I felt inspired to make my very own talkbox. Making one appealed to me not only because I enjoy building musical instruments, but also because it was an oppertunity to understand more about how the device works in its entirety.
What is a Talkbox?
A talk box or talkbox is an effects unit that allows musicians to modify the sound of a musical instrument. The musician controls the modification by changing the shape of the mouth. The effect can be used to shape the frequency content of the sound and to apply speech sounds (in the same way as singing) onto a musical instrument, typically a guitar (its non-guitar use is often confused with the vocoder) and keyboards.
Commercially manufactured talkboxes are typically too expensive for the quality of their output. Many dissatisfied customers claim these talkboxes have tinny output or weak drive coming out of the tube. This project aims to source parts that could be used to make a quality talkbox at a relatively affordable cost.
To achieve the desired sound, I would need a speaker driver with a very wide response frequency range so that I could manipulate some inhumanly high and low ranges to create interesting, full, and funky vocal sounds.
According to various sources, the human audio spectrum encapsulates the 20hz - 20khz frequency domain. Most of the extreme ends of those frequencies are a little displeasing or hard to hear, so I was fine for settling on something that hit most of them.
Eventually I chose this speaker driver from MCM electronics. While this driver is relatively cheap for getting such a wide range (100hz - 8khz), it did prove to be a bit tough to source adapters for and use with my live setup. I'll address those concerns in the "Conclusions" section below.
one (1): 1 3/8" x 18 Thread Per Inch (TPI) 40W RMS Midrange Driver
five (5) feet: 5/16" inner diameter plastic non-toxic tubing
one (1): 5/16" to " barbed hose adapter
one (1): " to 1 " bushing
one (1): 1 3/8" grounding bushing
two (2): O-rings
one (1): 1 female stereo audio phone jack
two (2): insulated copper wire
Adjustable Wrench that can fit 1" - 2" fittings if you find a sufficient adapter.
And / Or a straight edge screwdriver if you wish to use the rubber reducer method listed below.
Assemble the bushing and hose adapter; this is what connects the speaker driver to the tubing. This should be fairly straightforward if you bought compatible bushing and barbed hose adapters.
Next, we'll be creating an airtight seal between the talkbox and the hose bushing. There are many methods of doing this (including making a foam enclosure), but the main two I considered were:
Rubber Reducer method: The speaker driver I chose was rather hard to find air-tight adapters for, which ll elaborate on a bit further in section. I would suggest getting a 1 1/2" rubber reducer similar to this one (note: I t tried this, but it sounds like a promising alternative if you t find a sufficient adapter. The example also seems way too expensive. Maybe ll update this with a better example in the future). With some circular metal clamps, you could tighten each end such that it creates an air-tight seal. If you get it made out of rubber, s possible you could screw it in as well, cutting out the rubber and making a tight fit as you go.
Getting Lucky method: In my case, my father had a sufficiently-sized adapter in the depths of his toolbench. However, the adapter from the talkbox to the hose bushing was not air-tight; there was no connecting threading to the 1 1/4"bushing. To achieve an air-tight seal, we decided to use O-rings to seal the empty space between the bushing and the throat of the speaker driver. Using a wrench we were able to tighten the connection such that the O-rings we squashed tight into place.
Either of these methods should result in reducing the output of the throat of the speaker to a 5/16" barbed hose adapter.
Next, we'll need to wire up the female audio phone jack such that the amplified audio signal can be sent to the speaker driver. I had some insulated copper wire laying around, so I snatched two of them. One for the audio signal (red) and one for ground (black), and attached them to the corresponding leads on the speaker driver. Consult the technical specifications of your audio phone jack to know which contacts correspond to the correct leads on the speaker driver.
Finally, put your tube on the barbed hose adapter.
Plug your desired sound source (like a guitar, synthesizer, or laptop) into a pre-amp.
Plug the amplified signal into your talkbox.
Verify sound is coming out of the tube of the talkbox by creating sound from your source.
Place 1/2" to an 1" of tubing into the corner of your mouth, securing its position lightly with your molars. Make sure that s enough space between the back of your cheek and the opening of the tube so that sound is not blocked as you mouth the words. Avoid getting saliva into the tubing. That's just gross.
Mouth the phrasing of vowels and complete hard consanants with gusts of air or closing your mouth; the talkbox will only take shape of the sounds made by your throat, not your lips.
Put your mouth in front of a microphone that is hooked into the house mixer / main mixer. This is how the makes sound.
Satisfactory, but human component needs further iteration, practice, and polish.
Finding a suitable closure point for the speaker s throat was challenging; after going to many hardware locations in San Francisco and Seattle, I was unable to find anyone who could help me source a bushing, adapter, or reducer that would match the 1 3/8" inner diameter and 18 TPI dimensions of the speaker driver. If I was to do this again, I would first try to source a speaker driver that had more modern and standard throat sizes and threading so that I could readily find replacement parts should the unit break down or needed to be updated to fit in an enclosure. For more information, I suggest looking into National Pipe Thread (NPT).
Fortunately, my father had an adapter in his toolbox that ve ended up being the missing piece to the puzzle.
For some immediate improvements, I could try my hand at enclosing the beast, which would make it less of a hassle to deal with. Perhaps a future addendum is in order.