I just got an IPHONE 4 and while perusing some apps noticed that Peterson had one the emulates their long produced strobe tuner. I liked the fact that it was accurate to 1/10 cent (.001 semitone), cool. Peterson has a great reputation for tuning machines going back 60 years.
Anyway, I had a chance to talk with several of their Engineers on some esoteric topics.....
Since Fretted instruments use just or equal temperment, someone who has a sensitive ear routinely detunes certain strings to remove some of the enharmonicities that come out when you play chords. Typically certain harmonics are particulary troublesome since played as part of the chord the harmonic series of the individual notes clash and cause beating (this is what piano tuner use to tune intervals-they traditionally count beats). This beating is produced when the frequency between the harmonics and fundamentals are close enough to hear the beats (The beat frequency is the diffence in Hz between the note serie). If you listen you can pick up the anoying undertones.when
Anyway, Peterson is a bit anal about the whole issue so they produce all their tuners to 1/10 cent and incorparte in their more expensive tuners what they call sweeteners. The sweeteners adjust the "perfect" number derived mathematically to produce sweater sounds. For a banjo they suggested that the 2nd string should be flattend by about 6.5 cents to produce a more pleasing sound. Guitars and other instruments have a whole other series of sweateners derived by exerience and judegement. After all the physics goes out the window when we consider that we are using human ears and aesthetics.
According to Peterson they are working with James Taylor and other artists to incorporate and determine the most appropriate sweeteners.
For those of us that have trouble just playing the correct notes this obviously represents a level of attention that is academic for us but it is interesting to know that accomplished musicians worry about this issue to optimize their sound. Petersons, Strobo-clip has selectable sweeteners for a variety of instruments. No wonder is costs $69 instead of the normal cost for a tuner.
From a marketing and sales standpoint different Tuner manufactures can either appeal to the precision minded or the "keep it simple stupid crowd."
BTW, keyboard instruments don't have this issue since they use the tempered scale. (Tuning between songs with a keyboard just isn't that easy). But piano tuning really is a combining of physics, art and aural sensitivity.
Probably more info than most of you needed but I think it is interesting. Like all things the important thing is to play and make music. You can wake up now.