Push Those Buttons!

All about accordion bass systems!

Where Do I Start?


When it comes to the bass side of the accordion, many accordionists or even just onlookers just shake their heads. It’s so complicated! It has SO MANY buttons!

How can you play when you can’t see what you’re playing?

What in the world is Stradella?

Or Standard Bass?
Whoever heard of terms like Free Bass, B-System or C-System, Quint System, French 3/3 system?

It’s Not That Hard

Yes, there are a lot of terms and buttons!
Knowing the difference between the systems and the types of music they are capable of boosts not just your IQ, but your musical skills as well.  In my last article, Are You My Type?, we explored the Treble side of the accordion. Now…

Let’s push some bass buttons!

Atlantic IV 120 Fun_640
Standard/Stradella Bass

The stradella bass, also known as standard bass,  is the most common system used in accordions. With 6 rows of bass buttons, the stradella bass is a mix of single bass notes and chords: major, minor, 7th, and diminished.
The stradella bass allows rhythmic accompaniment as well as bass solos – providing the solos are within 1 octave range.
The single bass notes act like the upright bass of a band, with the chords being the rhythm guitar.
The most common system of Stradella bass is the 2/4 system – meaning there are two rows of bass notes and 4 of chords.
See below for an example:


Stradella Bass

French 3/3 System

The French 3/3 system is not as common in the United States (but it’s what I play!).
On this system, an additional row of single bass notes are added above the counter bass row. This allows more possibilities for bass solos as more single notes are easy to reach. And many more combinations of chords.
The rows of chords are as follows: Major, minor, and the last row is used for both 7th and diminished chords.

AL Stradella French Bass Chart
Bass Layout & Sizes

The layout of the bass notes follows the circle of fifths, leaving the most used notes (I, IV, and V) right next to each other.
Accordion sizes are often noted by the number of bass buttons they have. The most common being 12 bass, 48 bass, 72 bass, 96 bass, and 120 bass.
Hohner Sizes


Music Styles

The stradella bass is used for many styles of music, such as Latin, Popular, Folk, etc. They can be used for Classical music, but aren’t able to perform the multiple layers needed for some pieces, Bach for instance.
Check out the videos below of performers using the stradella bass.


Pietro Adragna performs Tico Tico – listen for the rhythmic accompaniment of bass and chords.

Alexander Shirinov performing Hommage a Piazzolla – you can also hear the rhythmic bass here.

Viivi Maria Saarenkylä perfoming Carnivale on a chromatic accordion with Stradella Bass.




Free Bass/Convertor Bass

The free bass is essentially another chromatic keyboard on the bass side of the accordion – but with bass notes.
Yes, each button on the free bass system is a single bass note!
Just like the Chromatic System (see my last article), there are both C & B Systems of free bass – but this time in mirror image to the right hand.
Free bass systems use the same two bass rows from the stradella system and add four more rows of free bass buttons. This allows the player to perform melodies in both the right and left hands.
A lot of free bass accordions have matching systems in both hands. There are exceptions, like with the piano accordion and occasionally there will be an accordion that has a C-sytem in the treble and a B-System for the bass. Petar Maric plays one like this in the video below.
There are more free bass systems than just C & B.
One worthy of note is the Quint System. This system can have 6 or 8 rows of buttons and allows an extra octave range – it was patterned after the bass rows of the stradella system.

Convertor Bass

You may hear the term ‘convertor bass’, that simply means that the accordion is not only free bass, but has a switch which allows you to change between free bass and stradella systems.
One press of the large switch and, voila! Stradella.
Another press of the switch and you’re back to free bass!
This allows the player to have the freedom to use either system.

Music Styles

Free bass systems are commonly used for Classical music as they allow parallel melodies at the same time.
Check out the videos below for some examples.


Sergey Teleshev performs Toccata & Fugue on a chromatic accordion with free bass.

Petar Maric performs the 4th Movement of Impasse.

Grayson Masefield performs on a piano accordion with an 8 row quint system.

Your Turn


The versatility of the accordion bass is truly amazing. Which do you play? What brand is it?

February 14, 2017

4 responses on "Push Those Buttons!"

  1. How cool! This was really interesting. I play a French 3/3 and didn’t know that about the diminished/7th row.

    I really enjoyed the videos – I think my favorite is the Hommage A Piazzolla. The free bass videos are inspiring too!

  2. Wow! I was always amazed at the bass buttons, and now I feel much more comfortable and even more excited to keep pursuing my knowledge of the accordion!

  3. The Accordion is such an amazing instrument! I am learning on a 120 button Stradella Bass. Before this article I thought the bass was limited just to the different number of buttons! I had no idea their were so many styles! My favorite performer was Pietro Adragna performing Tico Tico. I really enjoyed how he played in so many different styles and sounds. The Converter Bass sounded most interesting to me, however, it will be some time before I am ready to venture out from the Stradella Bass

  4. My Rolands are capable of changing bass systems at the touch of a button (including free bass). All this at a fraction of the cost of an acoustic freebass/converter model, which usually has only one version of bass/chord operation

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