My student has recently acquired a new Yamaha YM-410D 4-octave marimba. When it arrived, I went to the student's house and listened to it, which just did not sound right. I could hear the distinct ham/beat. I made a phone call to Yamaha about the tuning. The answer by Mr. Soejima was:

"YM-410D, according to the internal standard, lower two actaves are tuned to the 4th partial, but above that is tuned fuzzy. This is the case even to YM-6000."

Later, he made a correction that YM-6000 is tuned to 10th partial.

Hmmm... According to the catalog, YM-410D uses Top grade Honduras Rose Wood and uses S-curve tuning etc., which gives me an impression that it is an instrument with certain quality. I used to think that Marimba were tuned better than that, but is this the norm now a days?

Junko

Junko,
I have no idea what Mr. Soejima is talking about. I tune many, many Yamaha's each year and they are usually tuned very well, unlike Adams, for instance. I know most of the Yamaha model numbers but I'm not in my shop right now and am not sure which the #410D is.
However, there should be 4th and 10th partials tuned AT LEAST in the lowest octave. Then 4th partials AT LEAST up to C5. After that they sometimes get lazy, like Musser, and stop tuning even the 4th partial.
What do you mean by 'S-Curve"? Do you mean like the shape of the tuning curve in the lower end of xylophones?
Bill Youhass
FCM