Pressing a key just once, but it plays twice!!

[spenstar]

I noticed that if I play a key just right, it will cause the hammer to bounce and cause the note to play twice. Is this something that is ever used?

[1piano4joe]

Hi spenstar,

I noticed that on many digitals the key sort of dribbles or rebounds. The digital doesn't play the note twice.

It may be that the piano needs to be regulated?

I don't know, Joe.

[iansinclair]

It shouldn't.  Interesting effect, perhaps, a bear to control -- but the action needs regulating...

[quantum]

I've encountered this numerous times on vertical pianos.  It was often the case of the letoff rail needing adjustment.  In fact, on the vertical I used to have at home the letoff rail was notorious for working its way loose. 

Call your tech to look at it.

[spenstar]

Is it something I dare try and fix myself? I'm rather broke at the moment.

[quantum]

Some details on the instrument would help.  Digital, vertical, grand?

One of Glenn Gould's piano's had a similar bouncy key problem.  However, he was so enamored with the character of the instrument that he decided to record with it despite the problem. 

[spenstar]

It's a Yamaha upright

[quantum]

Is it under warranty?

[indianajo]

I've got a few notes on my 1941 Steinway console that do this hammer bounce at certain velocities.  They are in the fourth octave of course.  As pivots and pads are felt, I imagine a few of the ones in this highly used octave are worn.  I'll be replacing them in the future.  I'm neither in the economic class where expensive professional service is advisable.  If I have to do a job several times to get it right, so be it.  I'm a pretty good mechanic generally; your results may vary.  
This piano was inspected and rejected before I got there by the local Steinway flipper. That is how I ended up with it for 1/5 the price he charges for one.  A few issues are worth $4000 to me, and the tone is beautiful even if the action does require a little work.   

[hfmadopter]

 Bottom line, it's in the regulation. The hammers have to back check with the correct spacing to the stings when struck and the key still depressed. And as mentioned felts wear etc. setting up a bounce , if the combo of all thatis too close to teh string you get a double strike,if it's really too close you get a blocked tone.

indianajo: the book you bought about tuning and regulating covers this.

My grand sat for some years in it's life and when I went back to playing I had to adjust it for this, it's very common.