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Blüthner and the Aliquot Fourth String System

Aliquot2Generations of piano makers have been constantly attempting to improve the quality of their instruments. Julius Blüthner made an important contribution with the development of the Aliquot System. Patented for the first time in 1872, it was one more step that provided Blüthner’s well known warm and romantic sound. The patented Blüthner Aliquot System consists of an additional fourth string in the treble section which is not struck by the hammer. The fourth string vibrates by resonance, and introduces additional overtones which enrich the dynamic sound.

Does it work?
Many people are sceptical, but it is easy to test. Simply play a note alternately muting and then leaving the fourth string to vibrate.
It is surprising how loud the Aliquot string is even though it has not been struck by the hammer. Currently, the Patented Aliquot System employs an additional fourth string in the treble section attached directly to the bridge that is not struck by the hammers.
Aliquot 1The fourth string is stimulated to vibrate through sympathetic resonance when the other three strings are struck, which results in an acoustical system enriching the overtone spectrum. It produces a very dynamic sound, which is audible over a wide range. This unique effect conveys the resonant treble of the Blüthner piano. As an example, it is possible to experience this special effect in many piano compositions giving an added dimension in tone colour and dynamics. Another factor that is that all Blüthner strings are individually hitched. For optimum effect, precise tuning is essential. In today’s instruments the ‘aliquot strings’ are tuned in unison with the trichords.

Read more at Blüthner World


  1. keyboardkat Says:

    Steinway accomplished much the same thing with the use of secondary bridges, also called “aliquots,” behind the main bridges, just in front of the hitch pins. These tuned the nonspeaking section of the strings, creating more overtones and a more colorful sound. Usually they tune this part of the string to the fifth degree of the scale (of course several octaves higher than the main pitch. Other piano makers, such as Yamaha, Kawai, and Baldwin (in its pre-’70s grands) also used this method.

  2. Gabriel Weinreich Says:

    The freely vibrating string mounted on the same bridge is equivalent to a “permanent una corda” pedal (obvious if you think about it). Its effect is to increase the aftersound level compared to the prompt sound level. I wrote about this in the Journal of the Acoustical Society of America in 1977. A popular version appeared in Scientific American in January of 1979.

  3. Patricia Frederick Says:

    Our 1877 Blüthner concert grand originally had Aliquot strings all the way down to the D below Middle C; and in the top octave, there were TWO Aliquot strings per note. Unfortunately, some piano tuner working for a previous owner evidently got tired of tuning all the extra strings. Not only were the Aliquot strings removed; so were their agraffes, and all the holes for the tuning pins were filled in with wood putty!

    Restoring the Aliquot system in this piano would be a major undertaking, and since the piano sounds very lovely even without the extra strings, we are leaving it as-is at present. It is one of the favorite concert pianos in our Collection for non-French European music of its time. (Our 1877 Erard gets all the French gigs.)

    This 1877 Blüthner also is partially overstrung, not in the bass! The octave from D# to d# cross over the next higher strings, while the bass strings are flat, parallel to the spine. Very different-looking! If anyone is interested, I can send a photo…

  4. Glenn Vanstrum Says:

    I played a Bluthner, a totally rebuilt 6′ 4″, in tune. Having heard the hoopla about the aliquot string, I was enthused to try it. After giving it a good fifteen minute performance, playing multiple composers from multiple eras, I feel it is an experiment that didn’t work. The aliquot strings keep ringing for seconds after one releases the pedal, making the sound very muddy, and, at least for me, uncontrollable.

    I understand Debussy loved this effect, but even when I played Debussy it seemed to take away control from the pianist. As the dealer said, “This piano comes with its own acoustics.” Forget playing Baroque music, or even Beethoven. It sounds like you are playing in a large culvert.

    I ended up buying a Yamaha C7, a piano that gives me control over what is happening. Perhaps my trial of the Bluthner was overly hasty, or perhaps the piano wasn’t tuned properly, I cannot say. For me, at least, it was an interesting idea that didn’t work .

  5. rachel starritt Says:

    It’s interesting of you to say about your opinion towards a Bluthner grand, as this is one of my five contenders to choose from in buying a grand further down the line, as I am only 18 years old and doing the usual examinations, so I am like any normal person. For your own interest, the five contenders are two of which are european–Bluthner and Yamaha, and three of which are American: Baldwin, Steinway and Mason and Hamelin.

    Here is my opinion on a Bluthner grand.
    I love the richness, the quality in tone and I feel it comes to me like droplets of liquid. I have played on one in the college I attend and the sound quality comforts me, so to speak, especially when playing Chopin, Liszt or Debussy. It also gains good practise in terms of technical control, as it allows you to create your own resistance without the need for a fixed action–it gives you leeway to focus in order to control the sound, particularly in playing polyphonic Baroque repertoire–Bach or Scarlatti.

    I would say I would prefer Bluthner to Bechstein as even in the vintage era, the turn of the 20th century, its range of tone depth and sustain (particularly of the 4th string to enhance the trebble’s tone) wins over Bechstein, which in contrast, has this thin, bright sound quality mixed in with a lot of colour, which doesn’t, in my view, sound as satisfactory as on a Bluthner, where you get both.

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