Although rarely asked, I offer unequal temperament piano tunings for discerning Sheffield and Yorkshire piano tuning customers, if discussed prior to the piano tuning. When arriving at a piano tuning job, the default tuning system and pitch standard I choose would be equal temperament at A440 (which lines up with the majority of recorded music). This satisfies the vast majority of clients.
To those unfamiliar with the different tuning systems in music, Equal temperament is the standard tuning system of the current western world, and it involves dividing an octave into twelve equal parts, resulting in slightly imperfect fourth and fifth intervals and faster-beating major and minor thirds compared to earlier systems. Intervals are tempered in a way that makes all music equally “right” (or “wrong” depending on how you look at it) in all keys, hence the name equal temperament. It is in no way agreed upon that this is the best or the most musically-pleasing way to tune an instrument, only the most balanced across key signatures. Whatever gains are made in chords and keys being well-balanced, the unique and colorful characteristics of each key become lost in the trade off.
There are other reasons to request a non-equal temperament – If a customer is interested in medieval, renaissance or early baroque music for example, he or she may ask for an unequal temperament and an alternative pitch standard to compliment their repertoire. If that’s the case I’d also suggest a lower pitch standard than A440 – A415 tends to evoke the spirit of Bach more than anything else, but there’s something magical about A432 (the fundamental frequency of the universe, after all). For someone playing Bach and Handel, or earlier music, Wreckmeister III or Vallotti-Young are alternatives that give each key its natural color.
I also offer a wide variety of Pythagorean and Meantone temperaments for the open-minded customer. Please be aware that while such a job will yield exciting results, it will take me longer than usual due to Equal Temperament being so deeply ingrained in my psyche (tuning 3-4 pianos a day this way for 12 years, it becomes a force of habit). When tuning in an unequal temperament I have to be even more thorough with my checks to ensure the very greatest accuracy.