Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Tone 'strangulation' - what's causing this?

Dear techs,

I would appreciate it if you can tell me what might be causing the following problem in a couple of unisons in the treble:

• Each string in a unison is tuned to within 0.2 cents of pitch.
• Each string in the unison has good sustain after the initial attack. The other two strings in the unison are muted;
• When the mutes are removed and the note is played, immediately after the initial attack the tone gets "strangled", leaving just a thin ringing (on pitch).

Thanks in advance!

In rare instances, the strings are just out of phase enough that there is a cancellation of sound waves.

Checking string level or, believe it or not, very, very slight de-tuning of the unison can help.

Hi Jurgen,

Yes it's clearly a phase issue. I wonder what the root cause could be. Could it be slightly inaccurate cutting or pinning of the bridge, or else caused by a deformed capo?

I've got a Mother Goose leveling gauge; I'll check the string level. De-tuning works here to eh? I i've used it successfully to smoothen out twangy unisons.

A sluggish or wobbly hammer flange. The rebound is important.

Ah! Thanks for tip Keith. The 6-month regulation/voicing is coming up in February. I'll speak to the tech about it.

Shaping the hammer head will help to get the three strings in phase. The hammer must touch all the strings at exactly the same time.

I was thinking about this a little more. The note in question was not behaving this way when the piano was new. The tone quenching started happening about two months ago. So it could be that Keith's suggestion about a sluggish/wobbly hammer flange could be the cause.

Anyway, I'll have it seen to next month.

Thanks to all who posted. If anyone else has any suggestions please feel free to post!

Anything can (and will!) change over time - string level, string grooves, pinning....

Point noted! Us non-techs need the occasional reminder that pianos are not static things, and that's why regular regulation is needed.

The hammer is blocking. You said it didn't do this when new. It could be just adjustments.

You could always eliminate the problem by "strangulation." Sorry, been wanting to say that since the post started.

But whose neck would I wring?

I was trying to find the appropriate word, but 'quenching' popped into my head after I posted.

You used the right word. Quenching implies satisfaction or fullfilling where as strangulation implies death and no longer there

Both sounds like a great idea to me! Quenching the thirst and ridding the piano of noises by a slow but, yet, painful death.

When I worked for Peterson Pianos here in GR, we used to almost fight for the right to sledge hammer a piano to death. Ohhhh what FUN that was!!!! Smash um to bits!