Baby Grand VS Grand Pianos: What’s the Difference?

Welcome to LivingPianos.com, I’m Robert Estrin. Today I’m going to talk about the differences between baby grands and grand pianos. You might just think one’s bigger than the other. That is an intelligent observation. But really, there are 3 fundamental differences between baby grand and grand pianos. I’m going to break it down for you today.

The 3 basic differences are: String Length, Soundboard Area, and Action Geometry.

Let’s talk about each one of these aspects and the significance of them. Then you can determine what might be the right piano for you. Baby grands are typically around five feet long. That’s measured from the edge of the key slip to the farthest part of the lid. Whereas grand pianos are more like six feet in length. These are only approximate measurements. Some baby grand pianos may be 5′ 1″ or 5′ 4″. Grand pianos can be 6’3″, 6’4″, even 6’6″. When you get to 7-feet, that’s considered a semi-concert grand, which is another class of piano.

What’s the difference between a baby grand and a grand piano in regards to string length?

The physics of sound is such that a doubling of frequencies creates an octave. When something vibrates twice as fast, it creates an octave higher in pitch. Therefore, something twice as big will produce sound an octave lower. If you think about how short the top strings of a piano are, if you went doubling each octave, you would have a piano that stretches out way farther than your room! So how do they compensate for that? Even on a 9-foot concert grand piano, the strings aren’t nearly long enough in the bass to be twice as long for every octave in the treble. It’s compensated for by making the strings fatter in the bass. You notice the copper wound strings in the bass get thicker and thicker. Even the steel wound strings have different gauges from the top going down, getting progressively thicker. This way the piano doesn’t have to be ridiculously long in order to have the range of pitch that it has. The sound created by thicker strings that aren’t as long, have many strong overtones. Overtones, or color tones, exist in all vibrating objects that create pitched sounds, whether it’s a piano, or a bell, or anything that produces a pitched sound. If you blow through a seashell and create a pitch, it has overtones in it! That’s what gives the vibrancy of tone, and the differences in sound from one instrument to another.

The shorter a piano is, the stronger the overtones are and the less fundamental frequency you have.

When you’re playing a low note, particularly on a small piano, you’re actually getting more overtones than fundamental pitch. I remember as a kid I used to love to play with tape recorders. One time I recorded the lowest note of the piano. Then I played it back three or four times as fast. It sounded almost like a chord! The overtones are so strong. This makes it very difficult to tune smaller pianos, because the overtones can conflict with fundamental frequencies of higher notes. The purity of the sound is one benefit to having longer strings. And the longer a piano is, the truer the fundamental tones are, and the overtones are less prominent. So that’s one aspect of the sound of a larger piano. That’s a benefit because of string length.

The larger the soundboard, the richer the sound.

Sound systems that have bigger speakers tend to have more bass and a richer sound. It’s very difficult to get good bass out of small speakers. There are some technologies that can come close with baffles and tubing and subwoofers. But with just one diaphragm, like a piano soundboard, a bigger one is going to have a richer sound overall. Also, the placement of the bridges on the soundboard can be more centralized when you don’t have to cram everything into such a tight space as in a baby grand. The scaling of the piano design on a larger piano can be such that you can get better vibration of the whole soundboard from any of the registers. You get a more even sound from top to bottom on a larger grand piano than on a baby grand. So those are two sonic benefits of grand pianos.

What about the action?

Earlier, I mentioned action geometry. On a small piano, in order to fit everything into a small space, and to have the strike point in the right place, that is the point of the string where the hammer hits, the keys must be shorter. Not the part of the keys you see, but the part that is behind the fallboard. So when you’re playing on a baby grand, your fingers are very close to the central pivot point. Therefore, the key travel is far shallower, particularly when playing black keys, as well as white keys close to the fallboard. Whereas on a grand piano, these parts of the keys move much more, giving you better control with your hands on the keys when you’re not playing on the edge of the keys. This makes it easier to control with soft playing in particular.

So those are some of the benefits of grand pianos compared to baby grands.

These benefits multiply as you get to semi-concert and concert grand pianos. A 9-foot concert grand is the ultimate piano in terms of scale design, with the way the strings get larger and longer from the treble to the bass, as well as the placement of the bridges on a larger soundboard, and the action geometry giving you such an even feel, even when playing close to the fallboard. It is the ultimate playing and sonic experience! However, another aspect of piano size is that generally, larger pianos produce more volume. So this is another consideration for you. I hope this has been helpful for you! Thanks again for joining me, Robert Estrin here at LivingPianos.com, Your Online Piano Resource.

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