(video) Overblows and harps

Here are a few thoughts on overblows and harmonicas. These ideas are relevant to both setting up and playing overblows on the diatonic harmonica.

- Overblows, overdraws, overbends are just like regular bends. The same thing that causes a regular note to bend causes the note to overbend.

- Air flow makes the reeds move and resonance affects the frequency (pitch). This is basic to how the harmonica works.

- Resonance can make a reed stand still. Resonance is kinetic energy and it can greatly affect the frequency of a reed.

- Resonance has a strong effect on both reeds when regular bends are played. Regular bends are double reed bends and overblows are single reed bends - they have a different behavior and sound.

- Resonance has a weaker effect on the closing reed than the opening reed during an overblow. If you can't hold and overblow note, it's likely because the reed that's supposed to stand still is not standing still.

- There are several kinds of overblow. Which is your favorite?

- It’s technique, but it’s also the harp. You need technique to play overbends but you also need a harp that will respond to your playing.

A new take on embossing

"...Here's how you do it: Only emboss half the slot...."

Embossing is SO misunderstood.

Embossing decreases the amount of space between the reed and the slot. It's as simple as that!

Why do it?

- You want to improve response
- You want a little more volume
- You like a bright sound

Why would you not want to emboss?

- You don't like bright tone

Embossing doesn't fix anything!

Do not ever try to fix a problem with embossing. If a note doesn't play well, spending 30 seconds embossing won't help. And when you are not happy with the result and decide to emboss some more - this time with more force - you will probably overdo it and end up damaging the reed plate.

To fix a misbehaving reed, make the harp airtight and fix the shape of the reed. Once you have done that, you can try embossing to add a little extra juice.

Embossing isn't just for overblows!

It would be a challenge to set up a harp for overblows without embossing, but that doesn't mean you can't take advantage of the benefits of embossing on a general-purpose harmonica.

Also, in of itself, embossing doesn't make your harp play overblows any easier. Not to any useful degree anyway... Again, the shape of the reeds counts for a whole lot more.

The Dark side of embossing

Embossing can cause problems. If you overdo it, your reeds will start to sound thin and the high overtones will become more present. As you continue to emboss, you will start to hear the reeds buzz. If you continue further, you will make the reed seize.

None of this causes permanent damage; you can undo embossing. But if you force the reed while trying to fix the damage, you can wreck your harp.

Embossing a harp is a job that takes a few minutes. If you are spending more time fixing the damage than you are spending time embossing, you are doing something wrong! I'm not saying you should rush your work but if you are spending hours embossing, you should probably re-think your process.

Less is more: Get the advantages without the drawbacks!

Gentle embossing can offer you a lot of the advantages of embossing while avoiding 99 per cent of the drawbacks.

Here's how you do it: Only emboss half the slot.

Find a round metal object like a 10mm chrome-plated socket driver, or the tip of one of my pin vises.

Hold the object halfway down the slot and press down. Press about as hard as you press a touch screen phone. Move the round object towards the free end of the slot (towards the reed tip).

You won't be able to see the little ridge you have created on the inside of the slot just by looking at the reed plate. Feel the inside of the slot with your fingernail. Pick at the side to see if you have created a little ridge on the inside of the slot. If you feel nothing run the round object down the slot again, this time with a little more force.

Do it until you have used just enough force to create a ridge (or burr) on the inside of the slot. Repeat the process on all the other slots one at a time starting from the halfway point and going to the free end.

On the weighted low reeds, you may need to position the reed plate over the edge of a table so that the tip of the reed can "peek" out the bottom of the slot as you move your round tool towards the tip.

Next, check your work. Use this hand position and angle the reed plate to look through the slots:

The shortened view of the slot is a low-tech way to zoom in and see how close the reed is to the sides of the slot. No extra equipment required (Microscope, Light Table, etc...)

Push the tip of the reed through the slot while you are looking to see if the reed touches any part of the sides. You'll also see if the reed is off-center as you do this. If you embossed with gentle finger pressure you should still have lots of room on either side of the slot.

If you overdid it in some areas, you will see it using this view. You may also notice the reed has a prickly/buzzy sound or maybe it doesn't even plink? To fix it, push the ridge of metal back. Use gentle force in the areas you need to target so that you don't completely undo your work.

Use a round piece of metal like a reed tool or a safety pin.

Since you only worked on the front half of the slot, you should be able to get your tool in position from the under side of the slot. The reed won't be in your way, it will simply be pushed up a little. Plink the reed a few times and re-check.

Now, put the harp back together and play it! You should notice more responsiveness and louder sound.

The reed shape, gap and tuning should be unchanged after embossing this way because we only worked on the free end of the slot. Not bad for a few minute's work! This method is a real time-saver!

If you are interested in embossing to the fullest possible limits, try Full Slot Embossing.

FIXED! One in a thousand WORST harmonica reed plates!

A harp player bought one of my combs from Rockin Ron's and had a little trouble getting the harp to play well. Here's why!

Just like maybe one-in-ten harps plays really well from the factory, this one suffered from defect and was the worst of the bunch.

It's fixed, now.

This particular harmonica is a Delta Frost but these defects happen with EVERY brand of harp. There are no exceptions. The only harmonica free of defects is a proper custom harmonica.

My combs are here:

My tools are here:

USA harpists, find my products at Rockin Ron's:

Reed work PDF download

There are only two or three ways to change the shape or curvature of a reed. There are several ways to perform each of them and of course you can combine them in a million ways.

Here's a reference to doing reed work. It's a PDF file you can download for free! Click the image to download...


(The black arrows indicate pressure applied with a tool and the pink round spots indicate counter-pressure applied with your finger.)

Curve the tip down:

Curve the tip up:

Lower base of reed:

This is a description of how I get the proper view of the shape of the reeds:

Replace harmonica reeds just like you change strings on a guitar.

"You don't need to throw away a harmonica because of a blown reed."

Part 1
See Part 2: How to replace a reed on a diatonic harmonica.

Reeds fracture with use. You don't need to throw away the harmonica because of a blown reed. Just like broken guitar strings can be replaced, so can harmonica reeds. In fact, you can change a harmonica reed in the same amount of time it takes to change a guitar string (maybe less!)

Reeds don't usually break off, they just drop out of tune because of microscopic fractures. If you play hard you will blow out reeds faster. Plink a fractured reed over and over and you will hear the pitch drop until the reed just stops moving - and eventually falls off - because the fracture grows to the point where it's not microscopic anymore.

Harmonica reed replacement is simple but it's not always easy. Replacing harmonica reeds is a bit of a paradox.

The chicken or the egg? Where do you start?

The first thing you need to do to a reed that has been freshly replaced is adjust its curvature so that it plays well. This is much more involved than just gapping. Re-shaping reeds takes some time and practice to learn. As part of the learning process, you will probably damage some reeds and they will have to be replaced.

That's why replacing reeds is an advanced skill.

To guarantee the new reed sounds right, there are a few things to consider:

1- Fastening a reed onto a reed plate can do some funny things to its shape. You need to be able to check and correct the shape of a reed to have success 100 per cent of the time. See this reed work reference.

2- Taking a reed off and putting one back on may also bend the reed plate if you are not careful. It's important to try not to bend the plate as you work. You must check for flatness once you are done and straighten a crooked reed plate.

3- Don't forget about tuning. The new reed will probably be out of tune - sometimes factory-new reed are out by as much as 50 cents! You will need to tune it.

Most harmonicas use rivets to secure the reeds to the plate because it's very cost-effective to mass-produce them that way. But there are other - better - ways of fastening a reed to the plate. There is nothing special about using a rivet.

A reed that's attached to the plate with a screw will not sound any different than a reed attached with a rivet. What's important is that the reed is secure, straight and centered and has a proper shape/curve.

Using a screw will allow you to get the reed perfectly positioned and won't warp the reed plate. You can guarantee success 100 per cent of the time.

Suzuki reeds are welded onto the plate. They don't use rivets. You don't need to buy a welding torch. The reeds can be removed easily by twisting the rivet pad just like rotating a reed with a reed wrench. To fasten the new reed, you drill a hole into the new reed and into the plate and secure the replacement reed with a screw.

Where do you start? Just jump on in!

See Part 2: How to replace a reed on a diatonic harmonica for the procedure.

Part 2

How to replace a reed on a diatonic harmonica

Part 2

Part 1: Replace reeds on a harmonica just like you change strings on a guitar.

The procedure at a glance:

- Find a new reed.

- Remove the BAD reed and flatten the reed plate.

- Tap the plate to receive an M1.4 screw and flatten the plate.

- Put the reed in the slot and insert the screw all the way without tightening it.

- Use a reed wrench to position the rivet pad so that the reed is straight and centered. Tighten the screw.

- Snip off the other end of the screw with flush cut pliers and debur.

- Check the flatness of the plate.

- Adjust the reed shape and tuning.


I offer a kit with all the specialty items you need to replace reeds on all brands of harmonicas.

Reed replacement kit


Here's how you replace reeds:

Find a new reed. You can use a new reed from the factory (contact Hohner or Seydel) or scavenge a reed from a donor plate.

Reed scavenging tip: The 4 Draw on a D harp is the same reed as 4 Blow on an E harp. Also, on Marine Band harmonicas the same reed is a 6 Draw on a G or the 6 Blow on an A.

The new or scavenged reed's rivet pad has a hole in it but it's too small to clear the screw we will use.

You can enlarge the hole using a rotary tool with a diamond tip reamer. This method works on Brass and Stainless reeds. See the video below.

Alternatively, you can drill a 1/16" hole in the reed's rivet pad using a drill press. If you are working on a brass reed, you can do it by hand using a good quality drill bit and a pin vice. Hold the reed onto a wood block to drill.

Please note that Suzuki reeds do not have a rivet and you will need to make your own hole using a drill press. I do not recommend using a hand drill of a rotary tool for this.

This is the reed replacement spine and removal pin. The spine is the foundation we will use to remove rivets and to flatten both the reed plate and the rivet pad. The removal pin is made of hardened and tempered steel.

Place the reed removal spine on the brick or anvil. You CANNOT place it straight on a table or counter - the table surface will absorb too much kinetic energy.

A brick or anvil will make sure all the force is directed to the reed removal spine. This is the best way to avoid bending the reed plate and wrecking your harmonica.

Question: "What kind of brick should I use?"
Answer: A heavy one.

Place the reed on the flat part of the reed removal spine.

Position the flattening pin on top of the rivet pad and strike it with a hammer.

The new reed is ready to be installed.

Remove the BAD reed. Position the rivet head upside down in the hole in the spine.

Hold the pin over the rivet tip and strike the pin straight down.

It's best to strike two or three times with light force so that you don't have to drive the pin any deeper than necessary.

The rivet should fall through the hole. Discard the old reed and rivet.

Flip the plate around and place the rivet hole over the solid part of the spine.

Place the flattening pin on top of the plate and strike it with the hammer to flatten.

The hole is now flat. This is essential for the reed to go in straight and be well positioned.

Dip the M1.4 tap in mineral oil and tap the rivet hole. The tap cuts the screw thread into the hole. I don't use self-tapping screws. Self-tapping screws aren't sharp and require more force - we don't want to bend or warp the reed plate. Tapping the hole is an extra step but it's the safest and most precise way to guarantee success.

Flatten the reed plate against the spine once again with the flattening pin.

Place your finger behind the empty slot.

Lay the GOOD reed in the slot. Let the tip of the reed touch your finger and the inside of the slot. Tucked away like that, it won't move around as you insert the screw.

Pinch the reed and the slot and put the screw in.

Turn the screw until it's all the way in but not tight.

With the reed held in place loosely, hold the reed plate up to the light and look through the slot. Use a reed wrench to move the reed up, down, left or right as needed. Don't worry about rotation, just center the middle of the reed pad. Pinch it in place and tighten the screw.

I use long screws because they are much easier to handle. The long end of the screw needs to be cut.

Use flush cut pliers to cut the end of the screw off.

Debur the end of the screw using sandpaper or an engraver.

Tighten again and center the reed one last time. The reed should feel snug.

Use The F-Tool to straighten the reed plate as needed. Flatsand the draw plate to take care of the tip of the screw.

Check and adjust the reed shape. Try to make the reed straight when passing through the slot.

Look at the shape of the reed from the side. Focus your attention on the light you see through the slot as you push the reed down through the slot.

Change the shape of a reed by focusing pressure with a tool onto a specific spot. Use a finger to provide counter pressure from the other side of the reed. Plink the reed about ten times after every change you make to its shape.

When in doubt remember that if the tip of the reed is curved down and enters the slot before the rest of the reed, you will not (never, ever) get a good result.

See this reed work reference.

Tune the reed using this method: Tuning page


Got into trouble?

Problem: There is no way I can align the reed!
Solution: Enlarge the clearance hole in the rivet pad. Use a 5/64" bit or even a 3/32" bit. Flatten the pad.

Problem: I stripped the thread!
Solution: Use a larger screw. Tap the hole with a larger tap. Use M1.6. You can also step it up to M2. On the blow plate, you can use a screw and a nut, too.

Updated Reed Replacement kit (2015/12/20):

New Flattening Pin Design: The square flattening pin shown in the instructions has been replaced with a round pin with two different ends.

One end is to be used to flatten reeds and reed plates and the other is struck with the hammer. The flattening end has been hardened and tempered.

Hardening and Tempering steel

I visited Alchemy Studios in Bath, Ontario to meet Mitchell Elliott. He was kind enough to show me how to harden and temper steel to make some tools.

Until now, I have been limited in the kinds of tools I can offer. I haven't been offering a reed replacement solution because I haven't been able to make a proper pin for reed removal. What I have been able to come up with until now has been too small and quite brittle. Now that's changed.

These pins are hardened, tempered and one is also polished.

This is for reed removal:

The pin is easy to align. Its tip is small to drive out the rivet without warping the reed plate. It's hard enough to last a lifetime. It's tempered so it won't shatter.

I'll be putting together a complete reed replacement kit which will include an M1.4 tap, pin vise and Stainless Steel M1.4 screws. The kit will be available soon. Stay tuned!

Putting it all together

Looking for fast results? Want easier bends/overblows/overbends and better tone? Most player's needs can easily be met just by following the fundamental steps.

See also Five things you can do to make a harmonica play better.

Here's a quick reference to the process of upgrading a harmonica.

My method is broken down into two parts: Fundamental and Advanced.

Start here: Fundamental:

These are the things that are the most important to get right. I recommend you start with this. You cannot expect more advanced techniques to reach their full potential - or even have the desired effect - unless the foundation is solid.

Most player's needs can easily be met just by following the fundamental steps.

1- Making the harp airtight by straightening the reed plates (The Flatness tools) and flattening your comb. I can save you the work of flattening your comb by offering you my Dark combs™.

2- Precise tuning will augment your harps. They will sound better and stronger. I offer tuning tools to make the process a lot easier.

3- Consistent gapping. This is setting the resting position of each reed so that the reed responds equally to low and high breath force.
Gapping is only one part of what can improve the Dynamic Range Gapping is the last step you do, even if you do advanced work.


These techniques enhance the performance, volume and tone of each reed. These techniques are much more invasive than the fundamental techniques. Learning to do these techniques carries a greater risk of damaging your harp.

1- Reed work. The shape (curvature) of each reed can be greatly improved over the shape from the factory. The workers who assemble the harmonica don't usually have a lot of time to adjust the shape of the reeds. All you can expect from the factory is "good enough".
I offer a free PDF reed work reference guide.
I offer a solid brass reed shaping tool and a reed support tool/Plinker to make this easier.

2- Embossing. This brings the edges of the slot closer to the reed to bring out more volume, power and response from the reed. I offer a tool for this and instructions are available to download for free from that page.


Reed Replacement:

Reeds fail. Save money and learn to replace reeds on a harmonica just like you change strings on a guitar.

You can't become skilled at fixing harmonicas if you don't know how to change reeds. Likewise, you can't become skilled at changing reeds unless you know what it takes to make a reed play well. I can help you through the learning process. I offer a reed replacement kit and will give you all the support you need to reach success.

See also: How to replace a reed on a diatonic harmonica.

Custom Harmonica Comb - Andrew's method

I learned how to make combs from friends with over 100 cumulative years of machinist experience! This is my low-tech, high-precision method of making exquisite harmonica combs. You can use this method to flatten the stock comb on your harmonica to make it play better.

The diatonic harmonica is made of solid pieces that must fit together in a way that is airtight. Mass-produced harmonicas often are not airtight and can be improved with a few minutes work.

This process is usually a little faster but the using a camera slows things down a bit.

Use this process on Hohner Bamboo Laminate (Crossover and Thunderbird) combs or the stock Suzuki Manji comb. You can also flatten a comb made of Corian or any other solid-surface material using this method. Be careful not to drop Corian combs - they shatter.

Wooden combs will swell. To flatten wooden combs like the Seydel 1847 or Marine Band Deluxe/1896 combs, I recommend you seal the surface after you flatten. Check for flatness after you seal, too.

Do not use this method on recessed-type harmonicas like the Special 20, Session or HarpMaster harmonicas. Those harmonicas use a different design concept. Checking and adjusting flatness on those combs requires a different strategy. Straightening and flattening the reed plates will make the best of the thin plastic combs in those models and will offer you great results. For perfectly flat reed plates, use The F Tool™.

This is the comb tool™. I meticulously flatten the top edge. *Only* the top edge is flat - we will be using that edge as a reference.

My comb tool is a working copy of a high-precision straight-edge (some call this a machinist square) precise to .000025" per 6" (25 millionths of an inch). The original stays in a drawer! If I were to use it on every comb I make, it would eventually wear out.

You can get a set of my comb tools here: Comb Tool™.

We will be measuring flatness along the left-to-right axis.

We will be measuring flatness along the up-and-down axis. That means in between every tine.

We will be sanding the comb surface. Tape a piece of 220 grit sandpaper to a flat surface. I use a granite surface plate but any flat surface will do. Don't obsess about the flatness of your working surface. The only thing you need to make your comb perfectly flat is a flat reference.

Place the comb tool over the comb to distribute the weight of your fingers evenly over the surface of the comb.

Move the comb around in circles in both directions until it feels smooth. This usually takes a few seconds. Flip it over and do the other side.

Place the reference along the surface of the comb and hold it up to the light. Hold it only on one side so that you can see how the other side behaves.

Switch sides. this gives us a good clue as to where the comb is bowed and where to flatten.

Put the comb down on the flat sandpaper and apply finger pressure where you want to flatten. Drag the comb along the sandpaper. Check flatness and repeat until it's flat.

Rotate the comb so that you are checking the tips. One tine is leaky here. Flatten the other tines to fix this.

Check in between each tine.

Switch your grip from side to side to reveal where the curve is.

Apply finger pressure and drag the comb to fix.

This is flat.

You can use the tool to apply even pressure to a portion of the comb - just like you used your finger. If the comb was unflat in this area, I would apply pressure like this:

Use this technique on both sides to fix a curve that is concave downward.

In summary, the hard part is measuring flatness. Once you can tell where the comb is not flat, it's easy to fix.

Extra tips!

Here are some extra tips on using my comb tool:

Comb tool extra tips page

Perfect Pitch: Using breath dynamics for 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

The diatonic harmonica can be tuned to different temperaments.

Equal temperament is when each note is tuned to its exact pitch. When the notes of a chord are played together at ET, the chords can sound dissonant because the harmonics aren't in sync. Just intonation means some of the pitches are tuned a little sharp or a little flat so that when played together, the chords sound very smooth. The harmonics are in sync.

Here is a diagram of the waveforms of the tonic and third superimposed:

On the top, you can see that at ET, only one cycle is in sync. On the bottom at JI, every fourth cycle is in sync. That note needs to be 13 cents flat to sync up.

Here is a diagram of the the waveforms of the tonic and the fifth superimposed:

On the top line, at ET, only one cycle is perfectly in sync and we can see it rapidly go out of sync as you move away from the center. On the bottom line, every third cycle is in perfect sync. The interval of the fifth is a powerful sound (guitar players call it a power chord!) because the waveforms are in such harmony. But it only took 1.5 cents to disrupt the timing and make it sound less powerful.

There is no way you can tune a diatonic harmonica to within 1.5 cents accuracy by looking at the needle on a chromatic tuner.


Harmonica reeds don't always vibrate at the right pitch. If you apply too much air flow, the reed will vibrate too slowly and the pitch will go down. The note will sound flat. That's because you are making the reed move a lot further that it is designed to do (greater amplitude) and it has to travel a greater distance with every vibration.

Likewise, if you play the reed with much lower breath than intended, it will hardly move. Since it will only travel a short distance, it will make the trip is less time and the frequency will go up - the note will sound sharp.

Fortunately, there is a very large "sweet spot" where the reed responds to a range of air flow and can stay reasonably on pitch - within a few cents - even if you don't always use the same breath force to play that note. That's why we can play the diatonic harmonica with such a large range of dynamics.

The fact that the pitch varies by a few cents with breath force is both a curse and a blessing when it comes to tuning.

It's a curse because you can't just tune each hole to a specific note. You need to offset the tuning of each reed so that you meet the following criteria (to name a few):

- the single notes are on pitch
- octaves are on pitch
- the other intervals (fifths, thirds) are on pitch
- the three blow and two draw are enharmonic equivalent (the same note) but they are not the same note (blow three is a fifth, draw two is the tonic; each one has a different offset.)

To meet all these criteria you need high precision. That's where using dynamics actually comes in handy.

Longer reeds flatten more than shorter reeds as you increase air flow. When you play two reeds at the same time you can count on the lower reed to flatten more that the top reed as you increase air flow (because it's longer).

So if two reeds are very close to being in tune, say, they both register the same on the chromatic tuner but you hear beats when you play them together, you can tell which one is tuned higher by playing with increased breath force and listening to what happens.

- If the beating slows down or disappears when you increase air flow, the bottom note is a little sharp.
- If the beating gets worse with increased flow, the top note is a little sharp.

Here's another way of looking at it. This is an animated GIF of two waveforms superimposed. The waveforms are an octave apart. Both waveforms lengthen (drop in pitch) as breath force increases. The lower note in the octave is sharp but with increased breath force it goes into tune with the higher note for a short moment.

In this case, we should either tune the lower note a little sharper or flatten the higher note.

The effect of flow rate on pitch

Here's an example of using breath dynamics to tune with precision:


Subscribe to RSS - blogs