Duo-Art Playing Too Loud
By Pete Knobloch
In making a graph using the measurements given on 08.22.96, I did use the stack as the bleed. I drilled a hole in a spare elbow and glued a hose nipple to it. This then connected to the vacuum gauge using a 5/32 inch hose. The elbow is connected to the treble side of the stack and this is where all of my readings were taken from. I put a roll in the piano and set the tempo level so the paper wouldn't move. With the motor turned on, I removed the appropriate hoses to the Dynamic Value Box and took the readings. To take the Theme readings, I opened up the Treble Theme Value and took these readings. None of the hammers were activated when the readings were taken.
Because of my comment about the piano playing too loud, I thought that I would quantify this statement for a reference. With the regulator adjusted to a maximum of 20.5 inches as found in the graph and playing "American In Paris", the piano will play at a volume of 90-92 decibels (db) maximum when both accordions are collapsed at level #15 and the Crash valve disabled.
This 92 db level is much lower than what I was seeing when I first brought up this subject on 96.08.16, but I don't know how much louder it was. The 92 db level is what I would call pretty loud, and I can live with it. I would like to reduce this db level to about 88 db. At first I was worried that reducing this level would take away from the magnificent sound coming from the piano when playing a medium loud passage but I haven't seen this yet. There is still such a large dynamic change heard in the playing that it seems to add to the playing pleasure since you don't have to cover your ears any more.
[ Ed Note: 92 decibels absolute sound pressure is _very_ loud.
[ Could you tell us more about your sound-level measuring equipment
[ and the set-up.
At this point the most logical direction to take is to look at the hammers. They may have "turned to stone", as quoted by Spencer Chase. If I adjust the regulator per the specification, I am sure that I will be getting vacuum levels of at least 35 inches. I know (through experience) the playing volume will go back into the painful playing mode by doing this. By working on the hammers and softening the piano, I should then be able to adjust the accordion distances and raise the vacuum levels back up to the normal specifications. Doing both of these changes should make the piano play more softly at the 5 inches #0 setting and more softly at the 35 inch vacuum level.
I plotted the Dynamic level vs. vacuum levels from 96.08.22 on graph paper. They tracked very closely from level #6 to level #14. There is a slight downward curve between level #0 and level #3 where both the Accompaniment and Theme vacuum levels dip together but follow each other almost perfectly. This could be because of the spill hole problems and adjustment. I might fix the spill value with the current accordion distances and see how the graph changes.
Another thing seen in this graph is that the Theme vacuum jumped at level #4. This could be because of the distance adjustment not right for #4 Theme.
At level #15, the Accompaniment level changed only 0.5 inches rather than the full 1 inch to follow a linear line.
Craig Brougher suggested that I set the values according to the book. I will go ahead and do both the accordion distance change and the spill adjust (in that order). I can then run the same test again and recheck the new vacuum levels and see how linear they look on graph paper. I probably won't leave the piano at this adjustment level for very long. I won't be able to do this until 2 weeks from now since other projects need to get done.
Something else that I am questioning is the vacuum meter that I just bought from Player Piano Supply. The needle is sticking at a reading of 2-3 inches when I turn the piano off. If I tap the meter, it goes back to 0 (which is really 1). I should return it and get a new one.
Pete Knobloch
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(Message sent Wed 28 Aug 1996, 16:47:08 GMT, from time zone GMT-0400.) |
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