| I believe you are worrying too much over this. Just tune it to standard tuning.
Stretch tuning is where the very low bass notes are lowered in pitch and the very high notes are increased in pitch. There are varying degrees of this and methods. You can over do it. Pianos can sound BIGGER using this type of tuning.
A lot of tuners have their own set of tuning parameters and are a bit bewildered when you mention 'stretch tuning'.
There are many many variations on equal temperament - types of stretch tunings are some of them.
Again, just ask your tuner to tune the piano the standard way and you will be fine. No need to fuss over 'stretch tuning'.
Have fun! |