Andrew's blog

How to bend notes on the diatonic harmonica: What is “Bending Energy”?

Warning: This blog post contains physics.

Here is an excellent demonstration of what happens when we bend notes. See what happens at the 3:00 minute mark.

When he finds the volume of the tube that is resonant to the frequency of the tuning fork, the sound increases. The frequency of the tuning fork stays constant though. Harmonica reeds are special because they can vibrate at different frequencies. We can make them vibrate faster or slower.

We apply “bending energy” by changing the size of the oral cavity just like professor Sumner Miller changed the size of the resonance chamber (cardboard tubes). Resonance is what applies kinetic energy to the reeds to make them vibrate at the desired frequency. If you want the reeds to vibrate slower, you open up your oral cavity to lower the resonance frequency. The reeds follow. It’s as simple as that.

Hopefully an understanding of what happens as you play a bent note can help you learn how to execute the technique.

Knowing the physics behind it allows you to free yourself from overthinking things. Don’t worry too much about tongue position, “U”-shape, “W”-shape, “G”-spot.... Just make an air pocket in your mouth and when you find the right size, the note will bend. Figure out what works for you to be able to re-create an air pocket of exactly the correct size every time you want to play that note.

It’s a little bit of a moving target when you consider that as you inhale, the tissues of your oral cavity will suck in and the air pocket will shrink. Conversely, the air pocket will grow when you blow bend because of the positive pressure. But with a little practice, your mouth will figure out how to keep the size of the air pocket constant despite these opposing forces.

Your ears play a big role in this. But the interaction between your voice, your ears and the shape of your oral cavity is automatic (or “autonomic”) so no instructions are required - other than to mention to make sure you can hear yourself play!

Overbends are just like regular bends!

Overbends are a little more complicated because we need both reeds (blow and draw) in the system to respond to the same resonance in different ways. One reed needs to stop moving while the other one needs to vibrate at the correct pitch. The trick is to get the reed that is standing still to stay still even though we are applying airflow to the system.

Sometimes out-of-the-box harps are set up to allow this to happen. Sometimes, they are set up to inhibit this. It’s the luck of the draw. It’s a common misconception than you need to practice overbends for years before you can become good enough to play them. The truth is that overbends require breath control, resonance control and a harp that is set up to cooperate.

It’s likely that you can learn to use overbends musically in a matter of weeks with the proper harp and some dedicated practice. You don’t need to build muscle over several years like a bodybuilder. You simply need to learn fine motor control.

I really enjoy watching professor Sumner Miller. Here is another video from the good professor where he describes the phenomenon of beating. Again, watch starting at the 3:00 minute mark:

Hearing the beating is a very important part of how to tune a harmonica.

More Better - ultra precision tuning

This is part of a series about tuning the diatonic harmonica

Part 1 - Tune a harmonica using your ears and a simple chromatic tuner
Part 2 - More Better - ultra precision tuning
Part 3 - Perfect Pitch: Using breath dynamics for tuning

Can you have too much of a good thing? Probably.

Can a harp be in absolute perfect tune? Maybe. If you don't care all that much about harmonica tuning (as long as your harp doesn't sound too bad), you can stop reading this and go back to playing some mean harp or practicing scales.

You can find a straightforward method of tuning a diatonic harmonica here: Tune a harmonica using your ears and a simple chromatic tuner. That will get your harp sounding very nicely.

If you obsess about tuning and are willing to spend a considerable amount of time and effort to get it perfect, read on!

In summary, we will apply the same strategy we've used to get the octaves in tune to the fifths and thirds.

Here's an important fact: You need to tune every Fifth with as much accuracy as you can.

What's so special about the fifths?

Every note of the scale has a purpose. For example, the Thirds and the Sevenths give the scale it's general sense of being (major, minor, dominant...). Fifths imply the Tonic; they are closely related to the tonic. It's important to get the tuning of the fifth (and fourth - same thing) right to make the chord sound nice.

Since the tonic and fifth are so closely related, the margin of error is considerably tight. A very small adjustment can go a long way. Often a fifths is tuned to less than 2 cents from ET, so even if you like your harps tuned to ET, you should be able to get away with such a small offset - you get the best of both worlds.

No chromatic tuner will be of help - you need to use your ears for adjustments this precise.

There are a lot of fifths on the standard diatonic harp. Every arrow in this picture is an interval of a fifth. If you enjoy tuning, dig in!

I can't tongue-block these intervals without affecting my embouchure which will cause some bending of these notes. That's not helpful to precise tuning! To play these intervals with a natural embouchure, you can isolate these pairs of reeds with the cover plates off using one finger to mute the thirds.

There are two chords on the draw plate so there are two different Fifths! The 2 draw is the tonic of the 1-2-3-4-5 draw chord. But the 4 draw is the tonic to the 4-5-6 minor chord. So 2-4 draw is an interval of a fifth, but so is 4-6 draw. These notes are repeated up the harp so 6-8 is a fifth, too.

Waitaminute! 6-8 is a fourth! Yes, but 8-6 is a fifth!. Take a minute to think about that...


And 8-10 is a fifth.

So tune the fifths with your tuner and then fine tune them with your ears. Play the tonic and the fifth and eliminate beating in the same way you eliminate beating when you tune octaves (using variable breath force to figure out which way to adjust the notes. See here: Tune a harmonica using your ears and a simple chromatic tuner. These beats are a little harder to hear than straight octaves, but they are there.

Thirds anyone?

Now that you have tuned all the fifths to perfection, can you use the same process with the thirds? Sure. Play the tonic and third together and fine-tune it to eliminate beats.

On the draw plate, there are two chords so there are two thirds. The 3 and 7 draw are major thirds to the 2 draw. The 5 and 9 draw are minor thirds to the 4 and 8 draw. Since major thirds need to be tuned about 12 cents flat to be just, you can compromise and find a nice sounding spot in between equal (0) and just (-12). Minor thirds are just at +16 but they sound pretty good near zero.

Remember the 5 draw is also the flat seventh of the 2 draw as well as the minor third of the 4 draw. What sounds good for one may not sound so good for the other. You decide what's best...

This is an extended French TunerTuner™. They are not part of my tool kit but are available separately.

What does it do? It helps tune the Fifths, Thirds as well as the Octaves on the blow plate.
The extended French Tuner works just like the regular FT. It plays octaves on one side and plays the other intervals on the other side.



You don't need any fancy equipment to tune properly. Even the French tuner/extended FT is just a tool to speed up the process. Use your ears. I'm posting these images to offer you a further visual example of what reeds to tune as pairs.

Some points to remember about tuning intervals relative to the tonic:

- If you play both the Tonic and the Fifth, a chromatic tuner will indicate the tonic - even if the tonic is the higher note (example, 3-4 blow or 6-8 draw.)
- Use your ears just like when tuning perfect octaves.
- If you hear beating that disappears when you increase your breath force, the bottom reed is tuned higher than the top reed (again, even if the bottom reed is the fifth)

Happy tuning!

The Harpoonist & The Axe Murderer at the Juno Awards 2015

Here's a clip of The Harpoonist & The Axe Murderer and friends at the Junos. Shawn Hall is playing one of my harps.

Harmonica Repair Basics

Rockin Ron told me that he gets quite a few technical support questions about replacement reed plates. The harmonica looks like a simple instrument but once you have taken it apart for the first time, you realize how important all the little details can be!

Here's a video about the basics of installing new reed plates into your favorite harp:

The F tool™

The F Tool™ is now available in the Tools section

A well-playing harp has a solid connection to the vocal tract. A big part of what makes it is easy to play, sound nice and fat is that it's airtight.

If it leaks air, the connection between your vocal tract and the instrument is weakened and the harp feels stiff. The tone is also weaker.

The good news is air leaks are fixable! In fact, that's the fundamental step in improving a harmonica. If you skip this step, you will usually end up working against yourself further down the line.

The detailed instuctions on How to use the F Tool are here.

Wonderful Cacaphony

Can you tune a bunch of diatonic harmonicas with precision in the same room at the same time?

Of course you can!

This is a moment captured during a harmonica repair workshop in Kingston, Ontario on 2015/05/16. The was the first time each of the participants used the French Tuner and I was impressed at how well they could tune a harp! Great job, guys!


I just bought a second CNC mill. It's bigger and faster than my first one. A second machine will improve my productivity and save time. It will also allow for redundancy. Routine maintenance won't affect my production time.

I bought it in the USA and crossed the border to pick it up the other day. I had to describe what I was bringing back to Canada to three different Border Services people and it's not an easy tool to describe.

Not being able to quite explain it in ten words or less, I said: "It's kind of like a 3-D printer".

Each one had the exact same reaction: "Really? Ahh! That's so cool!" they said and nodded...

I use my CNC mills to make combs, tools and a few other interesting tidbits I would never have conceived just a few years ago. Computer aided design (CAD) and computer aided manufacturing (CAM) is so accessible these days. Oscar Goldman was right! "We have the technology."

Event: Harmonica Retreat Workshop at Shared Harvest Community Farm

Wonderful organic food and world-class harmonica instruction are happening in Dunneville Ontario on the weekend of June 26th, 2015. Don't miss it!

Carlos Del Junco

Ronnie Shellist

Roly Platt

Workshops will include 3 chord song structure, comping vibrato and tone, using transcribe software to break down songs, demystify licks and learn your favourite runs, playing effectively and simply, 1st 2nd and 3rd position playing, tunings, rhythm playing, playing melodically, overblows, sitting in with a band, techniques, do's and dont's, harmonica maintenance (with Andrew Zajac) and group sessions with all the instructors.

Don't miss out on this opportunity to learn and play with three world class harmonica players/teachers, enjoy amazing food and have a true blues experience under the willows by the Grand River.


To register for the Harmonica Workshop please send an email to Also include your name, address, phone number and email address.

Dynamic Range

Here's a description of a harmonica's dynamic range and some of the things that improve or worsen it.

Warning, this is a pretty boring video.

Producing CNC milled combs revealed!

I design my combs myself and produce them using my CNC mill. Here's a breakdown of the process.

The combs are cut. Water is sprayed on the surface as the mill works to cool the bit as it cuts. Keeping the temperature down helps keep the bit sharp and prevents the finished comb from giving off a strong smell. Fresh off the mill, the combs look a little rough....

After a quick rinse....

Each comb is held in place with support bridges. Here, I have cut them free.

Then wash away the debris.

The rough combs need to be sanded polished and flattened. I first start working on the outer edges and tips of the tines.

Here the outer edges and tines are smooth.

Next, I flatten the top and bottom sides. I check for flatness using a reference. This comb is not flat and needs to be fixed.

After a little work, it's flat.

At this point, the combs are starting to look nice.

Next, I round off every edge. The front (tines, viewed from the side) is rounded.

...and the corners...

Next, I painstakingly work on the inside of every tine. I make sure each one is shaped for comfort.

These tines are comfortable on your tongue.

I start the process of lacquering the tips of the tines. I apply many thin coats instead of only a few thick coats. I do this to ensure the lacquer doesn't chip or crack. My aim is that they last a lifetime.

This is after one coat.

After several coats...

If it's dry and it looks wet, it's done!

Next, I polish the sides and back of the comb. The last step is to flatten the comb one last time to ensure it's going to deliver peak performance.

Combs get wrapped up immediately and are ready to be shipped.


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