Since I'll often play at low volumes, IAC on the CLP "sounds" interesting. Do you think it is any good?

from brochure:
http://download.yamaha.com/api/asset/file/?language=sv&site=se.yamaha.com&asset_id=46208

Intelligent Acoustic Control* provides a full, balanced sound
with rich lows and clear highs even at low volumes.

Volume adjustment is convenient for playing at home, where
sometimes others may prefer you play softly. You’ve probably
experienced the fact that when the volume is low, it is difficult to hear
treble and bass. On a Clavinova, however, the Intelligent Acoustic
Control (IAC) function automatically adjusts the sound, so you enjoy
proper sound balance even at low volumes. Additionally, the volume
dial automatically makes fine adjustments to the overall sound of the
speaker system (EQ) at low volume. This ability to adjust volume
without losing the rich and balanced sound is an exclusive Yamaha
benefit, ensuring you always play with the utmost sound quality.

Hello
I have this option on my NU1 and honestly did not hear the difference...
Marketing stuff ???
Btw, the sound is (with or without this setting) really good.

Do you play much with low volume?

I guess you could make a similar change with for example the equalizer on a CP5, but here it is automated in accordance with the selected volume.

I would suspect it is nothing more than EQ setting. Instead of fixed "Loudnes" curve they probably implemented several of them depending on the master volume (see http://en.wikipedia.org/wiki/Equal-loudness_contour).

Altering the function of the volume control to boost the bass (and sometimes the treble, too) when the volume control is set low ... this used to be called the "loudness" control. It appeared on even some of the cheapest audio equipment at least forty years ago.

So now they dress it up by calling it "Intelligent Acoustic Control". Wow!

It's just another piece of marketing trivia, akin to proclaiming that "this automobile comes equipped with tires!!!!"

For those of us who grew up in the 1960's, 1970's, home stereo equipment often had a Loudness switch which boosted the bass a little. It might have also boosted other ranges as well for all I know.

It was meant to be used at softer volume levels but I suspect many used it at louder levels for even more bass.

I remember listening to 'Portishead' on my father's lovely hi-fi during my high school years.. When nobody was at home, I'd turn the 'loudness' function on and enjoy the sensation of the room shaking.

I've haven't tried IAC yet, however the idea makes scientific sense.

Some previous discussion on this topic: Re: Volume on a d.p. equivalent to that of an a.p.

Greg.

I tried this on P-105 and couldn't find any difference when it's ON or OFF (using the built in speakers or headphones).
Maybe it's my ears.
Has anyone else noticed what actually I.A.C does.

Are you sure the P-105 has it? There's no physical button for it?

From my experience with the loudness effect in hi-fi systems of old, you are unlikely to get the same effect out of the limited range speakers that are built-in portable slab DPs. It requires a deeper bass range that can be felt for this effect rather than only heard. The difference is like going from a flat 2D to 3D.

I wonder if tools like Audition or Audacity can be used to detect what's going on?

yes, it there in the documentation and how to activate it. it's not on a separete button.