Interview with an exceptional concert piano tuner

Piano facteur, piano tuning and piano quality


This section of our website is for all those interested in piano tuning and seek to understand how this magical instrument produces sound. It is also here to help you distinguish the differences between piano concerts and Uprights. We receive many questions from our students who hesitate before choosing their piano or cannot find a tuner in their area. In order to respond to these questions, we turned to a piano specialist, both in the mechanical and the sound aspect. Hopefully an exceptional piano turner accepted to be interwieved  and respond to our students. Interview was conducted  by Frederic Bernachon (below):


We have great pleasure in introducing Jacques COQUELIN, piano maker, concert technician and tuner expert at the Court of Appeal of Aix-en-Provence. Jacques COQUELIN main activities are the maintenance of concert and music academy pianos and being expert in valuable pianos. During his long career he spent a considerable amount of time studying the price and restoration of Steinway pianos Bechstein, Bösendorfer. Since moving to Cannes Jacques COQUELIN prepares pianos for most major concerts in the south of France. He has tuned the pianos for Rubinstain, Aldo Ciccolini, Boris Berezovsky (photo below), Gabriel Taccino, Michel Béroff,  and many others.

accordeur coquelin berezovski


Jacques COQUELIN has agreed to answer our questions and those most frequent asked by our students. Below are our questions and his response:

Why do two new acoustic pianos - same brand and same model - have a different sound?

Answer: The soundboard, the piano soul is made of planks of spruce or fir, the conifer family. These boards, carefully selected from 8 mm to 10 mm thick, assembled, cut in quaters, that is to say in the direction of the grain to obtain a long line that is perpendicular to the regular surface of the soundboard panel. They are then glued together at the edges. The table is vibrated by the bridge that transmits the vibration of the strings. Its acoustic function is therefore to transform part of the mechanical energy of the strings into acoustic energy. The soundboard, maintained by the tables of bars, amplifies nothing; it radiates, sends sound waves that depends on the density of the wood. You should now understand the difference in resonance and tones between two identical piano models of the same brand and production line. This difference may also be explained by the density of the hammer felts that can be different from one mechanical to another. The felts are made out of wool, whose density may also vary when attached to the head of the hammers. For example, with fibres tightly packed, the sound is smooth; with very tight fibres however, the sound will be lighter. That said each will then have its own preference. A Preference that will be based on their own perception of sound and how it is listened to. Some prefer the smooth sounds, soft, hot: Gaveau piano, Bösendorfer, others will be attracted by lighter sounds: Pleyel, Yamaha, Steinway.

Why does an acoustic piano, even if you do not play it, un-tune itself with the time?

Answer: This is a physical phenomenon. The tension of a piano, around 10 to 15 tonnes, is what makes the whole instrument harmonise. The strings are very tight and will tend to relax, whether we play them or not. The humidity conditions along with temperature will also have an important role in keeping the piano in tune or not. Temperature differences will accentuate the de-tuning, if the weather is dry or there is active heating. It is highly recommended to maintain a constant relative humidity between 50 and 65% for a temperature between 18-21 °C, especially during the winter.

How many times a year, or on what occasion do you recommend tuning a piano?

Answer: Ideally an acoustic piano should be tuned four times a year, one for every season change, for the reasons mentioned above. The minimum maintenance for a piano is twice a year: Once when we open the windows turn the heating off: so autumn and spring. It also depends on the frequency with which the piano is used: if you play 6 hours a day, you have to tune it on a monthly basis (be sure to request a subscription from your tuner).

What is the difference between the tuning of the ear and the tuning of an instrument? What does this phrase mean: tune to 442?

Answer: A piano tuned according to the perfect mathematical values with an electronic tuner will have a very high accuracy but will falsely perceived by the human ear. The tuner however, will know how to interpret the sound, to a degree of accuracy that is pleasant to the ear and is precisely tuned to the equal temperament. This requires practice, which enabled the sound to acquire colour, and will seem pure to the human ear. This is called the musicality of a piano, it will be an "imperfect" perfection in the physical sense. In our time and despite technological advances, no machine or tool can replace the human ear. The tuner still has a bright future!

442 is the frequency in Hertz: this means 442 vibrations per second. Pianos, in orchestras, are tuned to 442 Hertz. This standard means that all instruments can be tuned to the same frequency.

What difference is there between tuning and a piano’s setting? Why should we check the piano’s setting and how often?

Answer: There is a major difference between tuning and a piano’s setting. Whilst tuning (2 hours) we are working on the sound by adjusting the tones. The purpose of the tuning, besides making the piano harmonise and enhancing the accuracy of its sound, is to develop musical taste. When we reset the piano however, we are working on the mechanism, the keyboard, the dampers and adjusting the pedal settings (forte and piano: piano-forte). Felt Hammers are set to hit the strings optimally to obtain the best acoustic performance in the interpretation of works performed by the pianist. Several hours-from 12h to 20h, are necessary for a full adjustment to achieve a proper functioning piano mechanism. Getting a good feel, seems so simple in theory, yet remains complex in practice.

Does the piano’s age have any significance? And what is the life expectancy of a piano?

Answer: The age of a piano is very important to be able to give it a market value estimated at its fair price. It depends on its condition, its wear, the date of its construction and its country of origin. It can thus be compared with the price of a new single instrument or equivalent. It is recommended to be wary and to call a professional in the piano market, or an expert close to the courts (see the list of your district’s court) before committing to a purchase! To know the age of the piano you will need its serial number to check against the records of the related company on the internet or by contacting a well-known professional.

For example, for a low market acoustic piano, known as an "industrial piano" its cost is between £2,500 to £3500. You should know that these pianos have a relatively short life span on a musical level, and are not intended for use beyond 7 years, such a piano has a significant discount to its resale. For a mid-range piano, its cost is of the order of £8000 to £14 000 , the lifespan is about 30 years if regularly monitored and maintained by a professional.

For the high-end up-right and grand pianos, the prices for major brands of upright pianos start from £20,000 to £40,000 and £35,000 and £115,000 for grand pianos. Their life span is similar to that of a human being in good health, which is 75 years and above.

Old pianos built at the start of the century, do they have any value?

Answer: These pianos usually do not have a high market value, however for historical reasons they are symbols of an era. On the other hand, some musicians look for these pianos for their feel and their authentic romantic sound.

What is the difference between an upright piano and a grand piano?

Answer: The arrangement of strings and their lengths are different on an upright piano and a grand piano. The sound of an upright piano spreads vertically, whilst the sound of a grand piano is horizontal, that is why the latter has a lid to direct the sound.

What is the importance of the size of a piano?

Answer: The height or length of a piano determines the length of the strings. The longer or higher the piano is, the better its dynamics. Under the trained fingers of a pianist the dynamics will be more easily controlled thus better transitions between pianissimo and forte.

Do you have a preference for certain piano brand, or type of mechanic?

Answer: I have a strong preference for European brands made in Germany; with regard to the mechanics, I prefer a Renner mechanical due to its accuracy and sturdiness.

Which acoustic piano brand would you recommend for a low budget (around 2000 or 2500 pounds)?

Answer: With this budget it is better to buy a good used European produced piano, instead of new "industrial" entry-level product from Asia.

For an amateur who wishes to buy a used acoustic piano is it possible to detect certain defects without professional help? Of course, the minimum is to bring in a piano tuner for this purchase.

Answer: An amateur cannot detect defects and especially not hidden screws on a used or new piano when he or she makes the purchase. If you plan to buy a piano of a certain value, it is recommended to involve a piano maker (a specialist of the chosen brand) or a tuner or an expert (you can find the official list of experts nominated and approved by the court in your area).

In France : Please also refer you to the French Association of piano tuners and repairers (AFARP) to help you find a specialist of this association in your area (you can contact the central office located in Le Mans +33 02 43 43 03 81 ).  Unfortunatly for the moment we cannot advise you for UK.

What does  "the double escapement" mechanics mean?

Answer: The hammer escapes in front of the string and is stopped during its fall by a catcher, whereas a spring system allows the catcher to be repositioned under the hammer (second catcher on top of the bridge). The pianist can then replay the note before it returns to its rest position, allowing greater speeds. The system was developed and invented in 1822 by a piano genius piano maker, Sebastian Erard. This invention improves touch, allows better control of the technique whilst also increasing the flair. This the double escapement  is present on all pianos from the early 20th century. It does not apply to the vertical mechanics of an up-right piano except on special order.

What is the best brand of pianos for you now?

Answer: I have a clear preference for the brand Steingreaber built in Bayreuth followed by Grotrian-Steinweg brand (Braunschweig) and Bechstein (Berlin), Bösendorfer (Vienna) and Seiler (Kitzingen).

Is it better to have a light or a heavy keyboard? Can we change the resistance on a piano?

Answer: Indeed, the resistance of a piano can be changed. The classic resistance depth is around 10mm, it can be set between 12mm and 9mn by using a driving wedge. For a good balance for the keys, the latter resistance must be weighted to an average of 50 grams. The traditional method involves placing pellets in the key with the corresponding amount of pellets required to get the sinking weight quoted above. The balance depends on the weight of the hammer for a 10mm depression, a mass of 50g, the rise of the key before getting to 25g, this balance should remain in these standards, otherwise the feel will be heavier and will be badly repeated.

Consequently, a keyboard that is too light will be, of course, be easier for the pianist, but will not produce a powerful sound, and a keyboard that is too heavy will cause muscular problems for the one who plays it.