Plugins, Virtual Instruments

The Harmonica For Garageband (A Step-By-Step Guide)

Written By : Andrew Siemon

If you’re looking for a harmonica VST from Garageband, look no further than the Serpo plug-in from JD Tech. You can get it either from Vst4Free at the link below or from AudioPlugingsForFree. 

Serpo on Plugins4Free and AudioPluginsForFree

From what I understand, the Serpo plug-in is the only Apple-compatible FREE plug-in that comes with a harmonica built into it, so for now, it’s the best option available to you. Truthfully, you could probably find an alternative out there like, however, this is the only free one available to my knowledge. 

How to Use Serpo’s Harmonica 

The notes of the harmonica are subject to change, depending on the type of harmonica.

For instance, real-life harmonicas actually come in a variety of formats, with most of them using the Key of C Major, the most common key signature in Western Music Theory, or at least the key signature on which the rest of music theory is based. 

From what I can tell, Serpo’s harmonica is actually a chromatic harmonica, which means that it’s not tied to any particular key signature. Each note of the MIDI Keyboard or Garageband’s Smart Controls functions as it normally would for a software instrument. 

In other words, when you press ‘C’ on the Musical Typing, you actually get a C note from the harmonica, and when you press on a ‘C#’ you also get a C#. 

When you try to play a chord with it, which isn’t really possible with a harmonica in real-life, you end up with a bizarre sound. A harmonica is typically a melodic instrument.

In other words, it’s used melodically rather than harmonically which means you play each note one at a time, rather than in harmony which is different from playing the piano or guitar.  I mentioned this also in my guide on how to make a country song in Garageband.

Guitars and pianos can be played both melodically and harmonically; in single notes and then groups of notes played at the same time.

The same thing cannot be said for the harmonica. Groups of notes played at the same time are called chords and the online piano course PianoForAll is probably the best way of learning them.  

Due to the limiting structure of the harmonica, it’s much better to use the instrument to outline chords, rather than play all of the MIDI notes together. For instance, if you wanted to play a chord with the harmonica, you would have to play each note on its own. 

Explained another way, the harmonica plays chords melodically and as arpeggios, which means you’re playing the notes of the chord on a note-by-note basis. 

In other words, if you want the C Major sound, then you go ahead and play a C, E, and then a G. 

If you wanted to play a G Major Chord, you’d play a G, B, and a D. 

To play a G7 (G Dominant 7th), you’d play a G, B, D, and an F. 

Playing the Blues with Serpo’s Harmonica 

I would argue that playing the blues on the harmonica, like every other instrument, depends a lot more on the musical context than the actual notes that you play with the melodic instrument. 

In other words, it really depends on the chords that are playing in the background, rather than the notes you play on the lead instrument. The same rule goes for the accordion as well which you can also get for Garageband via my guide.

The notes you play on the harmonica are meant more for outlining the chords that make up the musical structure of the song. 

For instance, the most common musical phrase in blues is the 12-bar blues progression, which is I-IV-V7 (I have more songwriting tips here).

To play a bluesy sounding harmonica progression, you would just want to use a piano or a guitar like my PRS SE Custom 24 to outline those chords, and then you can go ahead and jam on the harmonica as you want, as long as you’re in the key of C.

 You could probably use the C Pentatonic scale as well, which you can find online just by Googling it.

How To Make Serpo’s Harmonica Sound Great 

Admittedly, VSTs never sound quite as good as the real thing, however, there are usually things that can be done to increase the quality of the sound.

With that in mind, there are a number of things that you can do to Serpo’s Harmonica to make it sound a little bit better, so we’re going to explore a few of those tactics here. 

In my article on how to make Garageband instruments sound a little bit more professional, I explore some of the most common practices for increasing the sound’s quality. 

However, in this tutorial specifically, we’ll tailor the changes specifically for the harmonica. 

There are 6 different tactics you want to employ to make the harmonica sound a bit better, including light slurs and staccato notes, compression, EQ, reverb, ambience, and then stereo-delay. 

1) Use Light Slurs and Staccato

By this, I mean that after you play a musical phrase on Serpo’s harmonica, you end the phrase with a very-lightly played note that’s almost like a slur. 

It looks a lot like what you can see in the image below: 


I find that this is a good way to actually make the MIDI harmonica sound a little more realistic and dynamic. 

Also, the note should be staccato as well, which means that you’re going to play the note as a short burst, rather than elongated. You can also see what this looks like in the image above.

2) Compression Setting 

The compressor is another way to make it sound a little bit better. You want to use the following settings to really bring some of the quieter sounds forward, and the louder sounds further back in the mix. 

I have the Compressor set up at the following controls: 

Threshold: -29.0dB 

Ratio: 6:1:1 

Attack: 35ms 

Gain: 2.0dB 


This is going to improve the quality of the sound.  

3) Channel EQ 

For the Channel EQ, I have it set it up like what you can see in the below: 


As you can see, I’ve attenuated some of the lower frequencies in addition to frequencies in the higher ranges. 

The purpose of this is to eliminate some of the unnecessary frequencies, and also make the higher frequencies less sharp and less prominent.

4) Delay 

The delay, in this case, is used just to thicken up the sound a little bit, to make it sound a little more full-bodied. 

I have the Delay set to the following parameters, as you can see in the image shown below: 

4-Harmonica-Delay-harmonica Edited

For the most part, the most important delay settings to change are the following: 

Left Note:1/8

Right Note: 1/8

Left Mix: 8% 

Right Mix: 8% 

This is going to make it sound just a little bit more interesting. I use this same Delay setting when I mix vocals as well.

5) Reverb 

For the reverb, I have it set pretty high, around 3/4 until the maximum setting. This pushes it a bit further back in the mix. 

This looks like what you can see in the image below: 


From what I can tell, this is the same way the harmonica is mixed in the classic song from Led Zeppelin/Willie Dixon, “Bring It On Home.”

6) Ambience

The same thing can be said for the ambience setting, which is also set to around 3/4 to the maximum. 

And finally, you could probably go ahead and pan the harmonica sound either further to the left or the right, depending on where you want it located in the stereo-image. 

You could even pan it hard to the left or right if you wanted. But I prefer to pan it to either +20 or -20. 

Using Zeppelin/Willie Dixon’s “Bring It On Home” As A Harmonica Example

Arguably one of the better blue songs out there is “Bring It On Home,” from Led Zeppelin, which was originally written by Willie Dixon and recorded by Sonny Boy Williamson in 1963. 

For the sake of this tutorial, I’m going to show you how to re-create this song in Garageband, that way you can go ahead and jam on the harmonica over this song. 

Frankly, the harmonica playing in this song is pretty awesome, so it should provide you with a nice foundation to work with, and then you can go and make your own tunes with it. 

How you re-create the chord progression in “Bring it On Home,” is really up to you. You can either grab the song from YouTube and then cut out the beginning of the song and insert it as a sample (read about how to sample here), or you can just play it on the guitar, assuming that you can play. 

The tablature looks like what’s shown in the image below: 


Once you’ve sampled “Bring It On Home,” or you’ve re-created it on the guitar, you can play the following notes on the harmonica and it’ll sound pretty good: 

D, E, G, A, B, D, E 

Playing any one of those notes is going to mesh well with the above progression.

However, of course, it’s not going to sound as good as the real-life harmonica played by Robert Plant, but it at least gives you an idea of what you can do with Serpo’s Harmonica. 

Youtube Video Tutorial 

The Harmonica For Garageband + How To Make It Sound Good


All-in-all, I would say Serpo’s harmonica obviously isn’t as good as the real thing, in fact, no plug-in is, however, with some tweaking of the dynamics and the use of reverb and ambience, I think you can make it sound a lot better. 

The more you play around with it, the better able you’ll be to make this thing sound good.

Andrew Siemon is the principal creator of, a website dedicated to all things music, including music production, music theory, recording, and how to use the most popular DAWs. Starting out as a metal guitarist, Andrew has since moved into other areas of music production including hip-hop and fusion

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