There is more than one approach to accordion tuning and it’s not always obvious what you sign up for when you have your accordion tuned. That’s why we would like to share a few of our thoughts with you on two common strategies of accordion tuning, namely the so called spot tuning and the full tuning. Let’s begin by discussing what those two terms mean.
Accordion tuning
A spot tuning is a partial tuning of the accordion. Not all reeds will be tuned but only those reeds that are out of tune. To determine which reeds are out of tune, the tuner will typically use it’s ear but a more systematic approach can be thought of too. For example, the tuner might only tune a reed, when it’s out of tune by more than 4ct or some other arbitrary threshold. As a result, some reeds will be perfectly in tune and others will be more or less in tune, depending on the aforementioned tuning thresholds.
A full tuning on the other hand means that all reeds will be checked and tuned. The tuner typically mutes the tremolo reeds and tunes the middle reeds to concert pitch. One after one, without exceptions. Once all those reeds are perfect in pitch, the tremolo reeds are tuned relative to those reeds. Usually, they are tuned separately first and then fine-tuned by ear together with the middle reeds in a second step. As a result, all reeds will be in tune.
So, what are the pros and cons?
The spot tuning has the main advantages that it’s much faster and hence cheaper than the full tuning. In fact, spot tuning is often the standard modus operandi when the accordion has very many reeds, e.g. on large 5-voice piano accordion. The difference between a spot tuning and a full tuning can be several days of work which translates into several hundred Euros in price. Finally, a thorough spot tuning by a good tuner can get you quite close to a full tuning.
The disadvantage of spot tuning is that your instrument will never fully be in tune. Fun fact: If the factory in which the accordion was manufactured used spot tuning (some do!), then it was actually never 100% in tune. But worry not, for a very well done spot tuning you won’t hear much of a difference in sound. However, you can expect your accordion to detune faster compared to fully tuned accordion. Here’s why.
Let’s assume a single reed goes more and more out of tune over time:

Now let’s take a look at what happens when many reeds slowly get out of tune:

The five reeds decay at the same individual rates in both graphics. The only difference is that for the full tuning all reeds start from perfect pitch while for spot tuning some start slightly detuned. A spot tuned accordion can be expected to go out of tune faster than a fully tuned accordion.
Which tuning should I get?
We carry out spot-tunings and full tunings alike and can see the benefit of both approaches. However, diatonic button accordions usually do not contain so many reeds. The price and time benefits a spot tuning offers are thus not so significant. That’s why we usually advise a full tuning. From our experience, the tuning will not only hold longer, it also feels and sounds more fresh.